WO2017155779A1

WO2017155779A1 - Vacuum glazing pillars for insulated glass units and insulated glass units therefrom

Info

Publication number: WO2017155779A1
Application number: PCT/US2017/020378
Authority: WO
Inventors: Jeremy K. Larsen; Margaret M. Vogel-Martin
Original assignee: 3M Innovative Properties Company
Priority date: 2016-03-07
Filing date: 2017-03-02
Publication date: 2017-09-14

Abstract

The present disclosure relates to pillars useful in the fabrication of insulated glass units, particularly, vacuum glazing, insulated glass units. The invention also relates to insulated glass units containing said pillars. The present disclosure provides a pillar for use in a vacuum insulated glass unit wherein the pillar includes a body comprising (i) a hub region and (ii) a plurality of arms radiating from and integral with the hub region, each arm comprising a neck and a lobe, the neck connecting the lobe to the hub region. The body has a thickness, a first contact surface with first surface area, an opposed second contact surface with a second surface area and at least one sidewalk The first contact surface comprises at least one first structure, integral with the first contact surface, the at least one first structure having a first structure base and a first structure face opposite the base, a thickness and a first structure face surface area.

Description

VACUUM GLAZING PILLARS FOR INSULATED GLASS UNITS AND

INSULATED GLASS UNITS THEREFROM

Technical Field

The present disclosure relates to pillars useful in insulated glass units (IGUs), particularly vacuum glazing, insulated glass units and insulated glass units containing the same

Background

Pillars useful for insulated glass units have been described in, for example, U.S. Pat No. 6,479, 112 and U.S. Pat. Publ. No. 2010/0260950.

Summary

Single pane, glass windows are generally poor thermal insulators and their use in buildings results in significant heat loss for the structure and leads to both higher building maintenance costs, due to higher heating/cooling costs, and higher initial fabrication costs, as the heating/cooling equipment specified for the building must be larger to compensate for the energy losses. Double pane windows, which include two glass panes with major surfaces substantially parallel to one another with a "space" or "gap" there between, are an improvement, as they provide a thermally insulating layer of gas, e.g. air, argon or the like, in the space between the window panes. Further improvement in a window's insulating capability can be achieved if the space between a double pane window is free of gas, i.e. the space is sealed and a vacuum is applied, removing the gas between the window panes. Windows of this type are often referred to as vacuum insulated glass units. However, in these window constructions, particularly in larger windows, which may be found in, for example, commercial structures, the pressure difference between the interior of the window and the exterior of the window may cause the glass panes to bow inward. The bow is undesirable, as it adds undesirable stress to what generally are brittle materials, e.g. glass, and, in extreme cases, the window panes may contact one another, thereby reducing the thermal insulating effect of the evacuated gap. To solve this problem, manufactures have placed an array of small structures, often referred to as pillars, between the glass panels of a double pane window, to prevent the panels from bowing when vacuum is applied. Windows with this array of pillars are referred to as vacuum insulated glazing units. Window structures, including vacuum glazing, have reduce the bow of the glass panels, with the addition of an array of pillars that supports the window panes and prevent the glass panels from bowing inward.

Vacuum glazing offers an improvement with respect to thermal insulation and the bowing of the glass panes is inhibited by the addition of an array of pillars. However, the pillars create an additional problem. The pillars have a higher thermal conductivity than the evacuated space between panes and each pillar creates a path of heat transfer between the two window panes that reduces the thermal insulating capability of the window. As such, it is generally desirable to keep the total pillar surface area in contact with the glass panes small, to reduce the heat transfer increase associated with the pillars. Additionally, for aesthetic reasons, the total surface area of the pillar and the individual pillars themselves are minimized, to minimize disruption of light propagation through the window and to minimize disruption of a viewer's view through the window. As the surface area of the total array of pillars is generally small, the compressive stress transferred to the pillars from the glass panes may be high and the pillars may fracture, crack and/or deform under the applied load. Thus, the pillars must have a suitably high compressive strength so as not to fail under the applied load. Conversely, the compressive stress the glass panes experience may be exacerbated at the edge of a pillar, as the edge, particularly a sharp edge, e.g. about a 90 degree angle between the face of the pillar contacting the glass and a corresponding pillar side-wall, may cause a stress concentration in the glass at the edge of the pillar. Many current pillar designs currently employ a sharp pillar edge and may be prone to cause the glass to fracture due to stress concentration generated by the edges of the pillar.

Overall, as one decrease the size of the pillars and/or the total surface area of the pillar array, to reduce heat transfer, the compressive stress on an individual pillar is increased and there is a greater tendency for the pillars to fail under the high loads. Thus, there is a need for pillars with improved heat transfer characteristics, e.g. lower thermal conductivity, that can withstand the compressive loads. The present disclosure provides new pillar designs that can lower thermal conductivity through the pillar, by reducing the contact area of the pillar with respect to the glass surfaces and/or improving the load bearing capabilities of the pillar and/or reducing stress concentration in the glass panes generated at the pillar edge. Additionally, if the pillar design includes an intricate structure, the design allows for fluid communication with the local environment throughout the pillar structure, preventing the trapping of undesirable gas within the pillar itself.

The present disclosure relates to pillars useful in the fabrication of insulated glass units, particularly, vacuum glazing, insulated glass units. The invention also relates to insulated glass units containing said pillars.

In one embodiment, the present disclosure provides a pillar for use in a vacuum insulated glass unit comprising:

a body comprising:

a hub region; and

a plurality of arms radiating from and integral with the hub region, each arm comprising a neck and a lobe, the neck connecting the lobe to the hub region; wherein the body has a thickness, Tb, a first contact surface with first area Abl, an opposed second contact surface with a second surface area, Ab2 and at least one sidewall, wherein the first contact surface comprises at least one first structure integral with the contact surface, the at least one first structure having a first structure base and a first structure face opposite the base, a thickness Tsl and a first structure face surface area, Asl . In some embodiments, the ratio of Tsl/Tb is between about 0.01 and about 0.6, the ratio of Asl/Abl is between about 0.03 and about 0.95 and/or the largest dimension of the body parallel to the first contact surface is between about 10 microns and about 2000 microns. The at least one first structure may be a plurality of first structures. If a plurality of first structures is used, each of the individual first structures of the plurality of first structures has a first structure face opposite its base, each individual first structure face having a surface area asl . The first structure face surface area, Asl, may then be the sum of the first structure face surface area, asl, of each individual first structure of the plurality of first structures. The opposed second contact surface of the body may further comprise at least one second structure having a second structure base and a second structure face opposite the base, a thickness Ts2 and a second structure face surface area, As2. In some embodiments, the ratio of Ts2/Tb is between about 0.01 and 0.6 and/or the ratio of As2/Ab2 is between about 0.03 and about 0.95. The at least one second stmcture may be a plurality of second structures. If a plurality of second structures is used, each of the individual second structures of the plurality of second structures has a second structure face opposite its base, each individual second structure face having a surface area as2. The second structure face surface area, As2, may then be the sum of the second structure face surface area, as2, of each individual second structure of the plurality of second structures.

Brief Description of the Drawings

FIG. 1 A is a schematic top view of an exemplary pillar according to one exemplary embodiment of the present disclosure.

FIG. IB is a schematic front view of the exemplary pillar of FIG. 1 A according to one exemplary embodiment of the present disclosure.

FIG. 2A is a schematic top view of an exemplary pillar according to one exemplary embodiment of the present disclosure.

FIG. 2B is a schematic perspective view of the exemplary pillar of FIG. 2 A according to one exemplary embodiment of the present disclosure.

FIG. 3 A is a schematic top view of an exemplary pillar according to one exemplary embodiment of the present disclosure.

FIG. 3B is a schematic perspective view of the exemplary pillar of FIG. 3 A according to one exemplary embodiment of the present disclosure.

FIG. 4A is a schematic top view of an exemplary pillar according to one exemplary embodiment of the present disclosure.

FIG. 4B is a schematic perspective view of the exemplary pillar of FIG. 4 A according to one exemplary embodiment of the present disclosure.

FIG. 5A is a schematic top view of an exemplary pillar according to one exemplary embodiment of the present disclosure.

FIG. 5B is a schematic perspective view of the exemplary pillar of FIG. 5 A according to one exemplary embodiment of the present disclosure.

FIG. 6A is a schematic top view of an exemplary pillar according to one exemplary embodiment of the present disclosure.

FIG. 6B is a schematic perspective view of the exemplary pillar of FIG. 6 A according to one exemplary embodiment of the present disclosure. FIG. 7 A is a schematic top view of an exemplary pillar according to one exemplary embodiment of the present disclosure.

FIG. 7B is a schematic perspective view of the exemplary pillar of FIG. 7 A according to one exemplary embodiment of the present disclosure.

FIG. 8A is an exploded perspective view of a vacuum insulated glass unit.

FIG. 8B is a side sectional view of a portion of a vacuum insulated glass unit.

FIG. 9A is an SEM image, top view, of an exemplary pillar according to one exemplary embodiment (Example 1) of the present disclosure.

FIG. 9B is an SEM image, perspective view, of the exemplary pillar of FIG. 9A according to one exemplary embodiment (Example 1) of the present disclosure.

Repeated use of reference characters in the specification and drawings is intended to represent the same or analogous features or elements of the disclosure. The drawings may not be drawn to scale. As used herein, the word "between", as applied to numerical ranges, includes the endpoints of the ranges, unless otherwise specified. The recitation of numerical ranges by endpoints includes all numbers within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5) and any range within that range. Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified in all instances by the term "about." Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein.

It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the disclosure. All scientific and technical terms used herein have meanings commonly used in the art unless otherwise specified. The definitions provided herein are to facilitate understanding of certain terms used frequently herein and are not meant to limit the scope of the present disclosure. As used in this specification and the appended claims, the singular forms "a", "an", and "the" encompass embodiments having plural referents, unless the context clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally employed in its sense including "and/or" unless the context clearly dictates otherwise. Throughout this disclosure the phrase "contact area" relates to the surface area of a pillar or pillars designed to be in contact with the surface of another substrate, e.g. glass panels of an insulated glass unit (IGU) or vacuum insulated glass unit (VIGU).

Throughout this disclosure the terms, "insulate", "insulating", "insulation", "insulated" and the like, refer to thermally insulating characteristics, unless otherwise noted.

Throughout this disclosure the term, "rounded" means a smooth, continuous curve having a shape that is at least one of a portion of a circle or a portion of an ellipse.

Throughout this disclosure the term "contact surface" of a pillar refers to a surface of a pillar designed to be adjacent a pane of glass in an IGU or VIGU.

Detailed Description

The present disclosure relates to pillars useful in the fabrication of insulated glass units, particularly, vacuum insulated glass units. The pillars of the present disclosure have reduced contact area which may be achieved by including structures within the contact surface of the pillars. This may lead to reduced thermal conductivity through the pillars and better overall insulating characteristics of a VIGU containing the pillars. The pillars of the present disclosure include a body. The body has a thickness, Tb, a first contact surface with first surface area Abl, an opposed second contact surface with second surface area Ab2 and at least one sidewalk The first contact surface comprises at least one first structure, integral with the first contact surface, the at least one first structure having a first structure base and a first structure face opposite the base, a thickness Tsl and a first structure face surface area, Asl . In some embodiments, the ratio of Tsl/Tb is between about 0.01 and about 0.6, the ratio of Asl/Abl is between about 0.03 and about 0.95 and/or the largest dimension of the body parallel to the first contact surface is between about 10 microns and about 2000 microns.

The at least one first structure may be a plurality of first structures. If a plurality of first structures is used, each of the individual first structures of the plurality of first structures has a first structure face opposite its base, each individual first structure face having a surface area asl . The first structure face surface area, Asl, may then be the sum of the first structure face surface area, asl, of each individual first structure of the plurality of first structures. The opposed second contact surface of the body may further comprise at least one second structure having a second structure base and a second structure face opposite the base, a thickness Ts2 and a second structure face surface area, As2. In some embodiments, the ratio of Ts2/Tb is between about 0.01 and 0.6 and/or the ratio of As2/Ab2 is between about 0.03 and about 0.95. The at least one second structure may be a plurality of second structures. If a plurality of second structures is used, each of the individual second structures of the plurality of second structures has a second structure face opposite its base, each individual second structure face having a surface area as2. The second structure face surface area, As2, may then be the sum of the second structure face surface area, as2, of each individual second structure of the plurality of second structures. A first draft angle, related to an included angle between at least one sidewall and the first contact surface of the body, is defined. In some embodiments, the first draft angle may be between about 90 degrees and 135 degrees. In some embodiments, the largest dimension of the body parallel to the first contact surface may be between about 10 microns and about 2000 microns. Several specific, but non-limiting, embodiments are shown in FIGS. 1 A through 7B and FIGS. 9A and 9B.

Referring now to FIG. 1 A, a schematic top view of an exemplary pillar according to one exemplary embodiment of the present disclosure. FIG. 1A shows pillar 100-1 which includes body 101 (a C-shaped body in this exemplary embodiment), having a first contact surface 110a, with surface area Abl, and an opposed second contact surface 110b, with surface area Ab2 (see FIG. IB) and at least one sidewall 120. First contact surface 110a includes at least one first structure 150a integral with first contact surface 110a. At least one first structure 150a has a first structure face 152a. First surface area Abl represents the projection of the shown major surface of the body and would include the surface area (circular area) of the at least one first structure 150a. At least one first structure 150a has a first structure face surface area, Asl . FIG. IB, a schematic front view of the exemplary pillar of FIG. 1A, shows pillar 100-1 including body 101 having sidewalls 120, first contact surface 110a and second contact surface 110b. Body 101 includes at least one first structure 150a having a first structure base 151a (represented by the imaginary dashed line) and a first structure face 152a opposite the base. In this exemplary embodiment, body 101 includes a plurality of first structures 150a, each first structure includes a first structure base, 151a (represented by the imaginary dashed line) and a first structure face, 152a, opposite the base. Each first structure has a first structure face surface area, asl (FIG. 1A). The surface area Asl (the total surface area of the at least one first structure) may then be the sum of the first structure face surface area, asl, of each individual first structure of the plurality of first structures. A first structure face, e.g. 152a, may be referred to as a distal end. The body has a thickness Tb. Tb may be the maximum distance between first contact surface 110a and second contact surface 110b.

The thickness of the at least one first structure is Tsl . The body may optionally include at least one at least one second structure 150b integral with second contact surface, having a second surface area As2. In this exemplary embodiment, body 101 includes a plurality of second structures 150b, each second structure includes a second structure base, 151b (represented by the imaginary dashed line) and a second structure face, 152b, opposite the base. Each second structure has a second structure face surface area, as2 (not shown, but analogous to asl). The surface area As2 (the total surface area of the at least one second structure) may then be the sum of the second structure face surface area, as2, of each individual second structure of the plurality of second structures. A second structure face, e.g. 152b, may be referred to as a distal end. The thickness of the at least one second structure is Ts2. A first draft angle, al, is defined as the angle between first surface 110a, e.g. a line parallel to first structure face 152a, and at least one sidewall 120. A second draft angle, a2, is defined as the angle between second contact surface 110b (as depicted by the horizontal dashed line extended from second contact surface 110b) and at least one sidewall 120. The first draft angle and the second draft angle may be congruent angles. In the embodiment of FIGS. 1 A and IB, draft angles al and a2 are each about 90 degrees. A dimension, Ld, is defined as the largest dimension of the body parallel to the first contact surface. The interior of the body is in fluid communication with the local environment through the opening, N, in the C-shaped body and/or the open region between the at least one first structure 150a. The body may have an exterior perimeter P, of length Lp.

In some embodiments, the C-shaped body is an annular segment shaped body, as shown in FIGS 1 A and IB. For annular segment shaped bodies of the present disclosure, the annular segment shaped body may include a segment angle theta (Θ). In some embodiments theta is between about 130 degrees and about 355 degrees, between about 140 degrees and about 355 degrees, 150 degrees and about 355 degrees, between about 160 degrees and about 355 degrees, between about 170 degrees and about 355 degrees, between about 180 degrees and about 355 degrees, or even between about 190 degrees and about 355 degrees, from about 310 degrees to about 355 degrees. In some embodiments theta is between about 130 degrees and about 358 degrees, between about 140 degrees and about 358 degrees, 150 degrees and about 358 degrees, between about 160 degrees and about 358 degrees, between about 170 degrees and about 358 degrees, between about 180 degrees and about 358 degrees, or even between about 190 degrees and about 358 degrees, from about 310 degrees to about 358 degrees. Segment angle theta may define the size of opening N. A cord drawn between one end of the C-shaped body and the other end, may also define opening N, e.g. a cord drawn between points PI and P2. In FIG. 1 A, point "C" represents the center point of the circular, annular segment shaped body, Ri represents the interior radius and Re represents the exterior radius.

In another embodiment, the present disclosure provides a pillar for use in a vacuum insulated glass unit comprising: a body comprising: (i) a hub region; and (ii) a plurality of arms radiating from and integral with the hub region, each arm comprising a neck and a lobe, the neck connecting the lobe to the hub region. The body has a thickness, Tb, a first contact surface with first area Abl, an opposed second contact surface with a second surface area, Ab2 and at least one sidewalk The first contact surface comprises at least one first structure integral with the contact surface, the at least one first structure having a first structure base and a first structure face opposite the base, a thickness Tsl and a first structure face surface area, Asl . In some embodiments, the ratio of Tsl/Tb is between about 0.01 and about 0.6, the ratio of Asl/Abl is between about 0.03 and about 0.95 and/or the largest dimension of the body parallel to the first contact surface is between about 10 microns and about 2000 microns. The at least one first structure may be a plurality of first structures. If a plurality of first structures is used, each of the individual first structures of the plurality of first structures has a first structure face opposite its base, each individual first structure face having a surface area asl . The first structure face surface area, Asl, may then be the sum of the first structure face surface area, asl, of each individual first structure of the plurality of first structures. The opposed second contact surface of the body may further comprise at least one second structure having a second structure base and a second structure face opposite the base, a thickness Ts2 and a second structure face surface area, As2. In some embodiments, the ratio of Ts2/Tb is between about 0.01 and 0.6 and/or the ratio of As2/Ab2 is between about 0.03 and about 0.95. The at least one second structure may be a plurality of second structures. If a plurality of second structures is used, each of the individual second structures of the plurality of second structures has a second structure face opposite its base, each individual second structure face having a surface area as2. The second structure face surface area, As2, may then be the sum of the second structure face surface area, as2, of each individual second structure of the plurality of second structures.

Referring now to FIGS. 2A and 2B, a schematic top view and perspective view, respectively, of an exemplary pillar according to one exemplary embodiment of the present disclosure, FIGS. 2A and 2B shows pillar 100-9 comprising a body 101 including a hub region 180 and a plurality of arms 190, radiating from and integral with hub region 180 (three arms in this exemplary embodiment), each arm 190 comprising a neck 192 and a lobe 194, the neck connecting the lobe to the hub region. The body has a thickness, Tb, a first contact surface 110a with first area Abl, an opposed second contact surface 110b with a second surface area, Ab2, and at least one sidewall 120. First contact surface 110a comprises at least one first structure 150a integral with the first contact surface, the at least one first structure 150a having a first structure base 151a (not shown, but similarly defined as the body of FIGS 1 A and IB) and a first structure face 152a opposite the base, a thickness Tsl and a first structure face surface area, Asl . In this exemplary embodiment, at least one first structure 150a is a circular, cylindrical shaped structure, having a thickness significantly less than its diameter. In this exemplary embodiment, at least one first structure 150a includes a plurality of first structures, four first structures, and the sum of their individual areas, asl, would be equal to Asl . In some embodiments, the ratio of Tsl/Tb is between about 0.01 and about 0.6, the ratio of Asl/Abl is between about 0.03 and about 0.95 and/or the largest dimension of the body parallel to the first contact surface is between about 10 microns and about 2000 microns. The at least one first structure 150a may be a plurality of first structures. If a plurality of first structures is used, each of the individual first structures 150a of the plurality of first structures has a first structure face 152a opposite its base 151a, each individual first structure face having a surface area asl . The first structure face surface area, Asl, may then be the sum of the first structure face surface area, asl, of each individual first structure of the plurality of first structures. The opposed second contact surface of the body may further comprise at least one second structure (not shown, but similar to that described in FIGS. 1 A and IB) having a second structure base and a second structure face opposite the base, a thickness Ts2 and a second structure face surface area, As2. In some embodiments, the ratio of Ts2/Tb is between about 0.01 and 0.6 and/or the ratio of As2/Ab2 is between about 0.03 and about 0.95. The at least one second structure may be a plurality of second structures. If a plurality of second structures is used, each of the individual second structures of the plurality of second structures has a second structure face opposite its base, each individual second structure face having a surface area as2. The second structure face surface area, As2, may then be the sum of the second structure face surface area, as2, of each individual second structure of the plurality of second structures.

FIGS. 3 A and 3B show a schematic top view and a schematic perspective view of an exemplary pillar according to one exemplary embodiment of the present disclosure.

Pillar 100-10 has a hub and arm structure similar to that of the pillar of FIGS. 2 A and 2B. The at least one first structure has been modified to be partial ring shaped (e.g. C-shaped) structures.

FIGS. 4A and 4B show a schematic top view and a schematic perspective view of an exemplary pillar according to one exemplary embodiment of the present disclosure.

Pillar 100-11 has a hub and arm structure similar to that of the pillar of FIGS. 2 A and 2B.

Pillar 100-11 has four arms and a total of five first structures, each in the shape of circular cylinders having a thickness significantly less than its diameter.

FIGS. 5A and 5B show a schematic top view and a schematic perspective view of an exemplary pillar according to one exemplary embodiment of the present disclosure.

Pillar 100-12 has a hub and arm structure similar to that of the pillar of FIGS. 4 A and 4B.

Pillar 100-12 has four arms and a total of four first structures located on the lobe of each arm, each first structure is in the shape of circular cylinder having a thickness significantly less than its diameter. The neck of each arm of pillar 100-12 is longer than those of pillar 100-11.

FIGS. 6A and 6B show a schematic top view and a schematic perspective view of an exemplary pillar according to one exemplary embodiment of the present disclosure. Pillar 100-13 has a hub and arm structure similar to that of the pillar of FIGS. 5 A and 5B. Pillar 100-13 has six arms and a total of six first structures located on the lobe of each arm, each first structure is in the shape of circular cylinder having a thickness significantly less than its diameter. The neck of each arm of pillar 100-13 is longer than those of pillar 100- 11. FIGS. 7A and 7B show a schematic top view and a schematic perspective view of an exemplary pillar according to one exemplary embodiment of the present disclosure. Pillar 100-14 has a hub and arm structure similar to that of the pillar of FIGS. 6 A and 6B. Pillar 100-14 has six arms and a total of six first structures located on the lobe of each arm, each first structure is in the shape of circular cylinder having a thickness significantly less than its diameter. Pillar 100-14 also include a through hole in the hub region. The neck of each arm of pillar 100-14 is longer than those of pillar 100-11.

The number of arms is not particularly limited. In some embodiments, the number of arms may be from 2 to 20, from 2 to 15, from 2 to 12, from 2 to 8, from 3 to 20, from 3 to 15, from 3 to 12, from 3 to 8, from 4 to 20, from 4 to 15, from 4 to 12 or even from 4 to 8.

In some embodiments, the pillar body of the present disclosure may include at least one through hole. The through hole shape may coincide with the general shape of the pillar body, however the through hole shape may be different from that of the shape of the pillar body. The shape of the through hole is not particularly limited. The shape of the through hole includes, but is not limited to, circular, ellipse, triangular, square, rectangular, hexagonal, octagonal and the like. A dimension, Tw, is defined as the largest dimension of the through hole parallel to the first contact surface. Ld is as previously described. The ratio of Tw/Ld may be between about 0.05 and about 0.95, between about 0.10 and about 0.95, between about 0.20 and about 0.95, between about 0.30 and about 0.95, between about 0.05 and about 0.90, between about 0.10 and about 0.90, between about 0.20 and about 0.90, between about 0.30 and about 0.90, between about 0.05 and about 0.80, between about 0.10 and about 0.95, between about 0.20 and about 0.80, between about 0.30 and about 0.80, between about 0.05 and about 0.70, between about 0.10 and about 0.70, between about 0.20 and about 0.70, or even between about 0.30 and about 0.70. The number of through holes is not particularly limited and may be between about 1 and about 20, between about 1 and about 10 or even between about one and about 5.

In some embodiments the pillar body of the present disclosure may include at least one channel. Addition of at least one channel to the first contact surface and/or second contact surface of the pillar body reduces the overall contact surface of the pillar body, as the area of the first contact surface and/or second contact surface are reduced by the inclusion of the at least one channel. This design feature may lead to reduced thermal conductivity, i.e. improved insulating capabilities, of the pillars of the present disclosure. If, for example, the body is in the shape of an annulus, inclusion of at least one first channel may aid in the evacuation of gas from interior of the annulus, when the pillar is used in a VIGU. The thickness, i.e. depth, of the channel is greater than that of the thickness of the at least one first structure and/or the at least one second structure. The number of channels is not particularly limited. In some embodiments, the number of channels may be between 1 and 50, between 1 and 35, between 1 and 20, between 1 and 15, between 1 and 10, between 2 and 50, between 2 and 35, between 2 and 20, between 2 and 15, between 2 and 10, between 3 and 50, between 3 and 35, between 3 and 20, between 3 and 15 or even between 3 and 10. The cross-sectional shape of the at least one first channel and/or the at least one second channel is not particularly limited and includes, but is not limited to, square, rectangular, triangular (v-shaped), truncated triangular, and the like. The at least one first and/or second channel may be linear along its length, i.e. a line, arced, curved, wavy, sinusoidal and the like. If more than one first channel is present, the first channels may intersect or may not intersect, e.g. parallel first channels. If more than one second channel is present, the second channels may intersect or may not intersect, e.g. parallel channels. In some embodiments, the length of the channel, i.e. the longest dimension, may be between about 10 micron and about 2000 microns. In some embodiments, the width of the channel may be between about 1 microns and about 1000 microns. In some embodiments, the thickness (Tc), i.e. depth, of the channel may be between about 1 micron and about 1000 microns. In some embodiments, the ratio of Tc/Tb between about 0.01 and about 0.50. In some embodiments, Tsl/Tc and/or Ts2/Tc, may be between about 0.01 and about 0.9. Similar to the body of a pillar, draft angles al ' ' and a2" can be defined for the sidewalls of the plurality of at least one first channel and at least one second channel. The values of draft angles al " and a2" are the same as those disclosed for draft angles al and a2.

In some embodiments of the present disclosure at least a portion of a first peripheral edge adjoining the first contact surface and the at least one sidewall and/or at least a portion of a second peripheral edge adjoining the second contact surface and the at least one sidewall may be at least one of a rounded peripheral edge and chamfered peripheral edge. Many of the previous embodiments depict pillars with a single sidewall. However, the number of sidewalls of the pillar body is not particularly limited. The body may have one, continuous side wall, as would be obtained if the shape of the body is cylindrical, elliptical cylindrical, C-shaped or spiral. In some embodiments, the body may have a plurality of sidewalls. In some embodiments, the plurality of sidewalls includes between 3 to 30 sidewalls, between 3 to 20 sidewalls, between 3 to 12 sidewalls, between 4 to 30 sidewalls, between 4 to 20 sidewalls, between 4 to 12 sidewalls, between 5 to 30 sidewalls, between 5 to 20 sidewalls, between 5 to 12 sidewalls, between 5 to 30 sidewalls, between 5 to 20 sidewalls, between 5 to 12 sidewalls, 6 to 30 sidewalls, from between 6 to 20 sidewalls, or even between 6 to 12 sidewalls.

When the body has a plurality of sidewalls, each sidewall has a first draft angle, al, and a second draft angle, a2. The first draft angle, al, for each sidewall is defined as the included angle between the first contact surface and the adjoining sidewall (as depicted in FIG. IB). The second draft angle, a2, for each sidewall, is defined as the angle between the second contact surface (as depicted by the horizontal dashed line extended from the second contact surface of FIG. IB) and the adjoining sidewall. The first draft angle and the second draft angle may be congruent angles. In some embodiments, al and/or a2, may be between about 90 degrees and about 135 degrees, between about 95 degrees and about 135 degrees, between about 100 degrees and about 135 degrees, 90 degrees and about 130 degrees, between about 95 degrees and about 130 degrees, between about 100 degrees and about 130 degrees, 90 degrees and about 120 degrees, between about 95 degrees and about 120 degrees, between about 100 degrees and about 120 degrees, 90 degrees and about 110 degrees, between about 95 degrees and about 110 degrees, or even between about 100 degrees and about 110 degrees. If al is greater than 90 degrees, the associated sidewall will be a tapered sidewall and the second contact surface is defined as having the larger projected surface area.

The thickness of the pillar body, Tb, is not particularly limited. In some embodiments, the thickness of the pillar body may be between about 10 micron and about 2000 microns, between about 10 microns and about 1500 microns, between about 10 microns and about 1250 microns, between about 10 microns and about 1000 microns, between about 10 microns and about 750 microns, between about 10 microns and about 500 microns, between about 50 micron and about 2000 microns, between about 50 microns and about 1500 microns, between about 50 microns and about 1250 microns, between about 50 microns and about 1000 microns, between about 50 microns and about 750 microns, between about 50 microns and about 500 microns, between about 100 microns and about 2000 microns, between about 100 microns and about 1500 microns, between about 100 microns and about 1250 microns, between about 100 microns and about 1000 microns, between about 100 microns and about 750 microns, between about 100 microns and about 500 microns.

Ld, has been defined as the largest dimension of the body parallel to the first contact surface. In some embodiments, Ld may be between about 10 micron and about 2000 microns, between about 10 microns and about 1500 microns, between about 10 microns and about 1250 microns, between about 10 microns and about 1000 microns, between about 10 microns and about 750 microns, between about 10 microns and about 500 microns, between about 50 micron and about 2000 microns, between about 50 microns and about 1500 microns, between about 50 microns and about 1250 microns, between about 50 microns and about 1000 microns, between about 50 microns and about 750 microns, between about 50 microns and about 500 microns, between about 100 microns and about 2000 microns, between about 100 microns and about 1500 microns, between about 100 microns and about 1250 microns, between about 100 microns and about 1000 microns, between about 100 microns and about 750 microns, between about 100 microns and about 500 microns.

The shape of the at least one first structure, which may be a plurality of first structures, and/or the at least one second structure, which may be a plurality of second structures, may all be the same or combinations may be used. In some embodiments, at least about 10%, at least about 30%>, at least about 50%, at least about 70%, at least about 90%), at least about 95%, at least about 97%, at least about 99% or even at least about

100%) of the at least one first and/or second structure are designed to have the same shape and dimensions. The at least one first structure and at least one second structure are typically made by a precision fabrication processes, e. g. molding and embossing, and the tolerances are, generally, small. For a plurality of structures designed to have the same structure dimensions, the structure dimensions are uniform. In some embodiments, the percent non-uniformity of at least one distance dimension corresponding to the size of the plurality of first and/or second structures, e.g. length, height, width of the face or width at the base is less than about 20%, less than about 15%, less than about 10%, less than about 8%), less than about 6% less than about 4%, less than about 3%, less than about 2%, less than about 1.5% or even less than about 1%. The percent non-uniformity is the standard deviation of a set of values divided by the average of the set of values mulitplied by 100. The standard deviation and average can be measured by known statistical techniques. The standard deviation may be calculated from a sample size of at least 5 structures, at least 10 structures, at least 15 structures or even at least 20 structures, or even more. The sample size may be no greater than 200 structures, no greater than 100 structures or even no greater than 50 structures. The sample may be selected randomly from a single region on the body or from multiple regions on the body.

In some embodiments, the body of the pillar is a precisely shaped body. "Precisely shaped" refers to a body, having a molded shape that is the inverse shape of a

corresponding mold cavity, said shape being retained after the body is removed from the mold. A precisely shaped body may still be considered precisely shaped, even though it may undergo some shrinkage related to curing, drying or other thermal treatments, e.g. calcinting or sintering, as it retains the general shape of the mole cavity from which it was original produced.

In some embodiments, at least about 50%, at least about 70%, at least about 90%, at least about 95%, at least about 97%, at least about 99% and even at least about 100% of the first and/or second structures are solid structures. A solid structure is defined as a structure that contains less than about 2%, less than about 1%, less than about 0.5%, less than about 0.1%, less than about 0.05%, less than about 0.025% or even 0% porosity by volume.

In some embodiments, the length of the at least one first and/or at least one second structures, i.e. the longest dimension, with respect to the cross-sectional area of the first and or second structures in a plane parallel to the first and/or second contact surface, respectively, may be between about 10 micron and about 2000 microns, between about 10 microns and about 1500 microns, between about 10 microns and about 1250 microns, between about 10 microns and about 1000 microns, between about 10 microns and about 750 microns, between about 10 microns and about 500 microns, between about 50 micron and about 2000 microns, between about 50 microns and about 1500 microns, between about 50 microns and about 1250 microns, between about 50 microns and about 1000 microns, between about 50 microns and about 750 microns, between about 50 microns and about 500 microns, 100 micron and about 2000 microns, between about 100 microns and about 1500 microns, between about 100 microns and about 1250 microns, between about 100 microns and about 1000 microns, between about 100 microns and about 750 microns, between about 100 microns and about 500 microns. If a plurality of first and/or second structures are used, they may all have the same longest dimensions or the longest dimension may vary, per design.

In some embodiments, the width of at least one first and/or at least one second structures may be between about 10 microns and about 1500 microns, between about 10 microns and about 1250 microns, between about 10 microns and about 1000 microns, between about 10 microns and about 750 microns, between about 10 microns and about 500 microns, between about 10 microns and about 250 microns, between about 50 microns and about 1500 microns, between about 50 microns and about 1250 microns, between about 50 microns and about 1000 microns, between about 50 microns and about 750 microns, between about 50 microns and about 500 microns, between about 50 microns and about 250 microns, between about 100 microns and about 1500 microns, between about 100 microns and about 1250 microns, between about 100 microns and about 1000 microns, between about 100 microns and about 750 microns, between about 100 microns and about 500 microns, or even between about 100 microns and about 250 microns. The plurality of first and/or second structures may all have the same width or the widths may vary, per design. If a structure has a tapered sidewall, the width of the structure may be taken at the distal end.

In some embodiments, the thickness of the at least one first and/or at least one second structures may be between about 1 micron and about 500 microns, between about 1 micron and about 250 microns, between about 1 microns and about 100 microns, between about 1 microns and about 50 microns, between about 5 microns and about 500 microns, between about 5 microns and about 250 microns, between about 5 microns and about 100 microns, between about 5 microns and about 50 microns, between about 10 microns and about 500 microns, between about 10 microns and about 250 microns, between about 10 microns and about 100 microns between about 10 microns and about 50 microns, between about 15 microns and about 500 microns, between about 15 microns and about 250 microns, between about 15 micron and about 100 microns, between about 15 micron and about 50 microns, between about 20 microns and about 500 microns, between about 20 microns and about 250 microns, between about 20 micron and about 100 microns, or even between about 20 micron and about 50 microns. If a plurality of first and/or second are used, the structures may all have the same heights, i.e. thickness, or the heights may vary, per design. In some embodiments, the percent non-uniformity of the height, i.e. thickness, of a plurality of first structures and/or a plurality of second structures may be between about 0.01 percent and about 10 percent, between about 0.01 percent and 7 percent, between about 0.01 percent and about 5 percent, between about 0.01 percent and 4 percent, between about 0.01 percent and 3 percent, between about 0.01 percent and 2 percent or even between about 0.01 percent and 1 percent.

In some embodiment, the height, i.e. thickness, of at least about 10%, at least about 30%) at least about 50%, at least 70%, at least about 80%>, at least about 90%, at least about 95%) or even at least about 100%> of a plurality of first and/or a plurality of second structures may be between about 1 micron and about 500 microns, between about 1 micron and about 250 microns, between about 1 micron and about 100 microns, between about 1 micron and about 50 microns, between about 5 microns and about 500 microns, between about 5 microns and about 250 microns, between about 5 microns and about 100 microns, between about 5 microns and about 50 microns, between about 10 microns and about 500 microns, between about 10 microns and about 250 microns, between about 10 microns and about 100 microns between about 10 microns and about 50 microns, between about 15 microns and about 500 microns, between about 15 microns and about 250 microns, between about 15 microns and about 100 microns, between about 15 microns and about 50 microns, between about 20 microns and about 500 microns, between about 20 microns and about 250 microns, between about 20 microns and about 100 microns, or even between about 20 microns and about 50 microns.

In some embodiments, the ratio of Tsl/Tb and/or the ratio of Ts2/Tb may be between about 0.01 to about 0.50, between about 0.03 and about 0.50, between about 0.05 and 0.50, between about 0.01 to about 0.40, between about 0.03 and about 0.40, between about 0.05 and 0.40, between about 0.01 to about 0.30, between about 0.03 and about 0.30, between about 0.05 and 0.30, between about 0.01 to about 0.20, between about 0.03 and about 0.20, between about 0.05 and 0.20, between about 0.01 to about 0.15, between about 0.03 and about 0.15, between about 0.05 and 0.15, between about 0.01 to about 0.10, between about 0.03 and about 0.10, or even between about 0.05 and 0.10.

In some embodiments, the plurality of first and/or second structures may be uniformly distributed, i.e. have a single areal density, across the first contact surface of the body and second contact surface of the body, respectively, or may have different areal density across the first contact surface of the body and second contact surface of the body, respectively. In some embodiments, the areal density of the plurality of first and or second structures may be between about 10/mm² to about 100000/mm², between about 10/mm² to about 75000/mm², between about 10/mm² to about 50000/mm², between about 10/mm² to about 30000/mm², between about 50/mm² to about 100000/mm², between about 50/mm² to about 750000/mm², between about 50/mm² to about 50000/mm², between about 50/mm² to about 30000/mm², between about 100/mm² to about 100000/mm², between about 100/mm² to about 75000/mm², between about 100/mm² to about 50000/mm², or even between about 100/mm² to about 30,000/mm².

The plurality of first and/or second structures may be arranged randomly across the first and /or second contact surface, respectively, or may be arranged in a pattern, e.g. a repeating pattern, across the first and/or second contact surface, respectively. Patterns include, but are not limited to, square arrays, hexagonal arrays and the like. Combination of patterns may be used.

Similar to the body of a pillar, draft angles al ' and α2' can be defined for the sidewalls of the plurality of first and second structures. The range in values of draft angles α and α2' are the same as those disclosed for draft angles al and a2.

In some embodiments, the ratio of the total area of the plurality of first structure faces, i.e. the sum of the area of the face of each structure, to the projected area of the first contact surface may be between about 0.10 to about 0.98, between about 0.10 to about

0.95, between about 0.10 to about 0.90, between about 0.10 and about 0.80, between about 0.01 and about 0.70, between about 0.20 to about 0.98, between about 0.20 to about 0.95, between about 0.20 to about 0.90, between about 0.20 and about 0.80, between about 0.20 and about 0.70, between about 0.30 to about 0.98, between about 0.30 to about 0.95, between about 0.30 to about 0.90, between about 0.30 and about 0.80, between about 0.30 and about 0.70, between about 0.40 to about 0.98, between about 0.40 to about 0.95, between about 0.40 to about 0.90, between about 0.40 and about 0.80, between about 0.40 and about 0.70, between about 0.50 to about 0.98, between about 0.50 to about 0.95, between about 0.10 to about 0.90, between about 0.50 and about 0.80, or even between about 0.50 and about 0.70. As an example of this ratio, as shown in FIG. 1 A, the total area of the plurality of first structure faces is the sum of the area, asl, of each individual first structure face 152a and first area Abl of first contact surface is the projected area of the C- shaped ring in FIG. 1 A. In calculating the area of the first contact surface and the second contact surface, the chamfered peripheral edge and rounded peripheral edge are not included, if present.

In some embodiments, the ratio of the total area of the plurality of second structure faces, i.e. the sum of the area of the face of each structure, to the projected area of the second contact surface may be between about 0.10 to about 0.98, between about 0.10 to about 0.95, between about 0.10 to about 0.90, between about 0.10 and about 0.80, between about 0.01 and about 0.70, between about 0.20 to about 0.98, between about 0.20 to about 0.95, between about 0.20 to about 0.90, between about 0.20 and about 0.80, between about 0.20 and about 0.70, between about 0.30 to about 0.98, between about 0.30 to about 0.95, between about 0.30 to about 0.90, between about 0.30 and about 0.80, between about 0.30 and about 0.70, between about 0.40 to about 0.98, between about 0.40 to about 0.95, between about 0.40 to about 0.90, between about 0.40 and about 0.80, between about 0.40 and about 0.70, between about 0.50 to about 0.98, between about 0.50 to about 0.95, between about 0.10 to about 0.90, between about 0.50 and about 0.80, or even between about 0.50 and about 0.70.

The pillar bodies of the present disclosure may include a peripheral edge. In some embodiments, at least a portion of the peripheral edge is at least one of rounded and chamfered. Pillars having bodies which include rounded and/or chamfered peripheral edges, are discussed in commonly assigned U.S. Patent Application Ser. No. 62/132054, entitled "VACUUM GALZING PILLARS FOR INSULATED GLASS UNITS AND INSULATED GLASS UNITS THEREFROM", filed March 12, 2015, which is hereby incorporated herein by reference in its entirety. Pillars having bodies which include a plurality of structures on their surfaces and/or at least one channel are discussed in commonly assigned U.S. Patent Application Ser. No. 62/132073, entitled "VACUUM GALZING PILLARS FOR INSULATED GLASS UNITS AND INSULATED GLASS UNITS THEREFROM", filed on March 12, 2015, which is hereby incorporated herein by reference in its entirety.

The pillar bodies of the present disclosure may further include a microstructure texture. In one embodiment, the present disclosure provides a pillar for use in a vacuum insulated glass unit comprising a body, the body includes a first contact surface and an opposed second contact surface, wherein at least one of a portion of the first contact surface and/or a portion of the second contact surface includes a microstructure texture. In some embodiments, a portion of both the first contact surface and second contact surface include a microstructure texture. In some embodiments one or both of the entire first contact surface and the entire second contact surface includes microstructure texture. In another embodiment, the present disclosure provides a pillar for use in a vacuum insulated glass unit comprising a body, the body includes a first contact surface and an opposed second contact surface, wherein the first contact surface includes a microstructure texture; and the second contact surface further includes at least one second structure, each second structure having a second structure face. Optionally, at least a portion of the second structure face include a microstructure texture. In some embodiments, if a plurality of second structures are used, all of the second structure faces include a microstructure texture. In another embodiment, the present disclosure provides a pillar for use in a vacuum insulated glass unit comprising a body, the body includes a first contact surface and an opposed second contact surface, wherein the second contact surface includes a microstructure texture; and the first contact surface further includes at least one first structure, each first structure having a first structure face. Optionally, at least a portion of the first structure face include a microstructure texture. In some embodiments, if a plurality of first structures are used, all of the first structure faces include a

microstructure texture. Pillars which include microstructure texture are discussed in commonly assigned U.S. Patent Application Ser. No. 62/132073, entitled "VACUUM GALZING PILLARS FOR INSULATED GLASS UNITS AND INSULATED GLASS UNITS THEREFROM", filed on March 12, 2015, which was previously incorporated herein by reference in its entirety. In some embodiments, the height of the microstructure texture is less than the height of the at least one first structure and/or at least one second structure. In some embodiments, the height of the microstructure texture is between about 5 nanometers to about 5 microns. In some embodiments, the microstructure texture may be in random pattern. In some embodiments, the microstructure texture may be in a pattern. In some embodiments, the length of microstructure texture is less than the length of the at least one first structure and/or the at least one second structure. In some embodiments, the length of the microstructure texture is between about 5 nanometers to about 5 microns. In some embodiments, the width of microstructure texture is less than the width of the at least one first structure and/or at least one second. In some

embodiments, the width of the microstructure texture is between about 5 nanometers to about 5 microns. The microstructure textured may be formed by techniques known in the art, including, but not limited to, sandblasting, beadblasting, chemical etching, plasma coating, polymer coating, release coating, cutting, sanding, grinding, replication, microreplication and the like.

Useful material and processes for fabricating the pillars of the present disclosure are included in pending U.S. Pat. Appl. No. 14/025958, titled "VACUUM GLAZING PILLARS FOR INSULATED GLASS UNITS", filed September, 13, 2013, pending U.S. Provisional Appl. Nos. 62/048972, titled "METAL OXIDE PARTICLES", filed

September 11, 2014 and 62/127569, titled GEL COMPOSITIONS AND SINTERED ARTICLES PREPARED THEREFROM", filed March, 3, 2015, which are incorporated herein by reference in their entirety. Useful material and processes for the fabrication of master tooling useful in the fabrication of pillars of the present disclosure include U.S. Pat. Publ. Nos. 2004/0068023, 2007/0264501, 2009/0099537, 2012/0012557 and

2015/0306363, which are all incorporated herein by reference in their entirety.

The pillar body may be at least one of a continuous, inorganic material or a polymer composite. Throughout this disclosure a "continuous inorganic material" is an inorganic material that spans the entire length, width and height of the pillar body. Due to the applied loads the pillars must withstand, it is preferable that they have a high compressive strength. The compressive strength of the pillar may be greater than about 400 MPa, greater than about 600 MPa, greater than about 800 MPa, greater than about 1 GPa, or even greater than about 2 GPa. In some embodiments, the compressive strength is between about 400 MPa and about 110 GPa, between about 400 MPa and about 50 GPa, between about 400 MPa and about 25 GPa, between about 400 MPa and about 12 GPa, 1 GPa and about 110 GPa, between about 1 GPa and about 50 GPa, between about 1 GPa and about 25 GPa, or even between about 1 GPa and about 12 GPa. The pillar body may have a thermal conductivity of less than about 40 W m^"2 °K^_1, less than 20 W m^"2 °K^_1, less than 10 W m^"2 °K^_1 or even less than 5 W m^"2 °K^_1. The pillar body may have a thermal conductivity of at least 0.1 W m^"2 °K^_1. In some embodiments, the continuous inorganic material includes a ceramic, such as alpha alumina, and is fabricated via the molding of a sol gel precursor (the "sol gel route"). In some embodiments, the continuous inorganic material includes at least one the following: ceramic nanoparticles (AI2O3, S1O2, Zr0₂, SiC, S13N4, and combinations thereof); ceramic precursors such as silsesquioxane and polysilazanes; sintered ceramic (AI2O3, S1O2, Zr0₂, SiC, S13N4, and the like); glass ceramic (the MACOR product, LAS-system, MAS-system, ZAS-system); glass frit; glass beads or glass bubbles; metal; and combinations thereof. The continuous inorganic material may be a sintered ceramic. The sintered ceramic may include, but is not limited to, at least one of zirconia, alumina, silica, silicon carbide and silicon nitride. In other embodiments, the polymer composite comprises a thermal or radiation cured composite made from thermally stable acrylate monomers or oligomers, or both, and a nanoparticle filler such as nanozirconia (the "cast and cure route").

Ceramics are often opaque in appearance due to the scattering of light by pores in the ceramic. In order to achieve even a limited level of translucency, the density of the ceramic is typically greater than 99% of theoretical. Higher clarity can require levels above 99.9% or even 99.99%. Two methods known in the art for achieving very high densities in ceramic materials are hot isostatic pressing and spark plasma sintering.

In one embodiment of the present disclosure, the continuous inorganic material may be crystalline metal oxide wherein at least 70 mole percent of the crystalline metal oxide is Zr0₂, wherein from 1 to 15 mole percent (in some embodiments 1 to 9 mole percent) of the crystalline metal oxide is Y₂ O3, and wherein the Zr0₂ has an average grain size in a range from 75 nanometers to 400 nanometers. The crystalline metal oxide may have a density of at least 98.5 (in some embodiments, 99, 99.5, 99.9, or even at least 99.99) percent of theoretical density.

In calculating the theoretical density, the volume of unit cell is measured by XRD for each composition or calculated via ionic radii and crystal type.

Ptheory = (NcA)/(VcNa)

Where Nc = number of atoms in unit cell;

A = Atomic Weight [kg/mol];

Vc = Volume of unit cell [m³]; and

N_a = Avogadro's number [atoms/mol].

In another embodiment the pillar body is formed from a reaction mixture that includes (a) 20 to 60 weight percent zirconia-based particles based on a total weight of the reaction mixture, the zirconia-based particles having an average particle size no greater than 100 nanometers and containing at least 70 mole percent ZrCh, (b) 30 to 75 weight percent of a solvent medium based on the total weight of the reaction mixture, the solvent medium containing at least 60 percent of an organic solvent having a boiling point equal to at least 150°C, (c) 2 to 30 weight percent polymerizable material based on a total weight of the reaction mixture, the polymerizable material including (1) a first surface modification agent having a free radical polymerizable group; and (d) a photoinitiator for a free radical polymerization reaction.

The zirconia-based particles can contain 0 to 30 weight percent yttrium oxide based on the total moles of inorganic oxide present. If yttrium oxide is added to the zirconia-based particles, it is often added in an amount equal to at least 1 mole percent, at least 2 mole percent, or at least 5 mole percent. The amount of yttrium oxide can be up to 30 mole percent, up to 25 mole percent, up to 20 mole percent, or up to 15 mole percent. For example, the amount of yttrium oxide can be in a range of 1 to 30 mole percent, 1 to 25 mole percent, 2 to 25 mole percent, 1 to 20 mole percent, 2 to 20 mole percent, 1 to 15 mole percent, 2 to 15 mole percent, 5 to 30 mole percent, 5 to 25 mole percent, 5 to 20 mole percent, or 5 to 15 mole percent. The mole percent amounts are based on the total moles of inorganic oxide in the zirconia-based particles.

The zirconia-based particles can contain 0 to 10 mole percent lanthanum oxide based on the total moles of inorganic oxide present. If lanthanum oxide is added to the zirconia-based particles, it can be used in an amount equal to at least 0.1 mole percent, at least 0.2 mole percent, or at least 0.5 mole percent. The amount of lanthanum oxide can be up to 10 mole percent, up to 5 mole percent, up to 3 mole percent, up to 2 mole percent, or up to 1 mole percent. For example, the amount of lanthanum oxide can be in a range of 0.1 to 10 mole percent, 0.1 to 5 mole percent, 0.1 to 3 mole percent, 0.1 to 2 mole percent, or 0.1 to 1 mole percent. The mole percent amounts are based on the total moles of inorganic oxide in the zirconia-based particles.

In some embodiments, the zirconia-based particles contain 70 to 100 mole percent zirconium oxide, 0 to 30 mole percent yttrium oxide, and 0 to 10 mole percent lanthanum oxide. For example, the zirconia-based particles contain 70 to 99 mole percent zirconium oxide, 1 to 30 mole percent yttrium oxide, and 0 to 10 mole percent lanthanum oxide. In other examples, the zirconia-based particles contain 75 to 99 mole percent zirconium oxide, 1 to 25 mole percent yttrium oxide, and 0 to 5 mole percent lanthanum oxide or 80 to 99 mole percent zirconium oxide, 1 to 20 mole percent yttrium oxide, and 0 to 5 mole percent lanthanum oxide or 85 to 99 mole percent zirconium oxide, 1 to 15 mole percent yttrium oxide, and 0 to 5 mole percent lanthanum oxide. In still other embodiments, the zirconia-based particles contain 85 to 95 mole percent zirconium oxide, 5 to 15 mole percent yttrium oxide, and 0 to 5 mole percent (e.g., 0.1 to 5 mole percent or 0.1 to 2 mole percent) lanthanum oxide. The mole percent amounts are based on the total moles of inorganic oxide in the zirconia-based particles.

Other inorganic oxides can be used in combination with a rare earth element or in place of a rare earth element. For example, calcium oxide, magnesium oxide, or a mixture thereof can be added in an amount in a range of 0 to 30 weight percent based on the total moles of inorganic oxide present. The presence of these inorganic oxides tends to decrease the amount of monoclinic phase formed. If calcium oxide and/or magnesium oxide is added to the zirconia-based particles, the total amount added is often at least 1 mole percent, at least 2 mole percent, or at least 5 mole percent. The amount of calcium oxide, magnesium oxide, or a mixture thereof can be up to 30 mole percent, up to 25 mole percent, up to 20 mole percent, or up to 15 mole percent. For example, the amount can be in a range of 1 to 30 mole percent, 1 to 25 mole percent, 2 to 25 mole percent, 1 to 20 mole percent, 2 to 20 mole percent, 1 to 15 mole percent, 2 to 15 mole percent, 5 to 30 mole percent, 5 to 25 mole percent, 5 to 20 mole percent, or 5 to 15 mole percent. The mole percent amounts are based on the total moles of inorganic oxide in the zirconia-based particles.

Further, aluminum oxide can be included in an amount in a range of 0 to less than

1 mole percent based on a total moles of inorganic oxides in the zirconia-based particles. Some example zirconia-based particles contain 0 to 0.5 mole percent, 0 to 0.2 mole percent, or 0 to 0.1 mole percent of these inorganic oxides.

The reaction mixture (casting sol) used to form the gel composition typically contains 20 to 60 weight percent zirconia-based particles based on a total weight of the reaction mixture. The amount of zirconia-based particles can be at least 25 weight percent, at least 30 weight percent, at least 35 weight percent, or at least 40 weight percent and can be up to 55 weight percent, up to 50 weight percent, or up to 45 weight percent. In some embodiments, the amount of the zirconia-based particles are in a range of 25 to 55 weight percent, 30 to 50 weight percent, 30 to 45 weight percent, 35 to 50 weight percent, 40 to 50 weight percent, or 35 to 45 weight percent based on the total weight of the reaction mixture used for the gel composition.

Suitable organic solvents that have a boiling point equal to 150°C are typically selected to be miscible with water, as the zirconia-based particles may be formed in a water base medium and the organic solvents may be added to the zirconia-based particle sol and the water removed through distillation, leaving the organic solvent in its place. In some embodiments, the solvent medium contains at least 70 weight percent, at least 80 weight percent, at least 90 weight percent, at least 95 weight percent, at least 97 weight percent, at least 98 weight percent, or at least 99 weight percent of the organic solvent having a boiling point equal to at least 150°C. The boiling point is often at least 160°C, at least 170°C, at least 180°C, or at least 190°C

The organic solvent is often a glycol or polyglycol, mono-ether glycol or mono- ether polyglycol, di-ether glycol or di-ether polyglycol, ether ester glycol or ether ester polyglycol, carbonate, amide, or sulfoxide (e.g., dimethyl sulfoxide). The organic solvents usually have one or more polar groups. The organic solvent does not have a polymerizable group; that is, the organic solvent is free of a group that can undergo free radical polymerization. Further, no component of the solvent medium has a polymerizable group that can undergo free radical polymerization.

Suitable glycols or polyglycols, mono-ether glycols or mono-ether polyglycols, di- ether glycols or di-ether polyglycols, and ether ester glycols or ether ester polyglycols are often of Formula (I).

R¹0-(R²0)„-R¹

(I) In Formula (I), each R¹ independently is hydrogen, alkyl, aryl, or acyl. Suitable alkyl groups often have 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms. Suitable aryl groups often have 6 to 10 carbon atoms and are often phenyl or phenyl substituted with an alkyl group having 1 to 4 carbon atoms. Suitable acyl groups are often of formula -(CO)R^a where R^a is an alkyl having 1 to 10 carbon atoms, 1 to 6 carbon atoms, 1 to 4 carbon atoms, 2 carbon atoms, or 1 carbon atom. The acyl is often an acetate group (-(CO)CH3). In Formula (I), each R² is typically ethylene or propylene. The variable n is at least 1 and can be in a range of 1 to 10, 1 to 6, 1 to 4, or 1 to 3.

Other suitable organic solvents are carbonates of Formula (II).

(II)

In Formula (II), R is hydrogen or an alkyl such as an alkyl having 1 to 4 carbon atoms, 1 to 3 carbon atoms, or 1 carbon atom. Examples include ethylene carbonate and propylene carbonate.

Yet other suitable organic solvents are amides of Formula (III).

(III)

In Formula (III), group R⁴ is hydrogen, alkyl, or combines with R⁵ to form a five- membered ring including the carbonyl attached to R⁴ and the nitrogen atom attached to R⁵. Group R⁵ is hydrogen, alkyl, or combines with R⁴ to form a five-membered ring including the carbonyl attached to R⁴ and the nitrogen atom attached to R⁵. Group R⁶ is hydrogen or alkyl. Suitable alkyl groups for R⁴, R⁵, and R⁶ have 1 to 6 carbon atoms, 1 to 4 carbon atoms, 1 to 3 carbon atoms, or 1 carbon atom. Examples of amide organic solvents of Formula (III) include, but are not limited to, formamide, Ν,Ν-dimethylformamide, N,N- dimethylacetamide, N,N-diethylacetamide, N-methyl-2-pyrrolidone, and N-ethyl-2- pyrrolidone.

The reaction mixture often includes at least 30 weight percent solvent medium. In some embodiments, the reaction mixture contains at least 35 weight percent, or at least 40 weight percent solvent medium. The reaction mixture can contain up to 75 weight percent, up to 70 weight percent, up to 65 weight percent, up to 60 weight percent, up to 55 weight percent, up to 50 weight percent, or up to 45 weight percent solvent medium. For example, the reaction mixture can contain 30 to 75 weight percent, 30 to 70 weight percent, 30 to 60 weight percent, 30 to 50 weight percent, 30 to 45 weight percent, 35 to 60 weight percent, 35 to 55 weight percent, 35 to 50 weight percent, or 40 to 50 weight percent solvent medium. The weight percent values are based on the total weight of the reaction mixture.

The solvent medium typically contains less than 15 weight percent water, less than 10 percent water, less than 5 percent water, less than 3 percent water, less than 2 percent water, less than 1 weight percent, or even less than 0.5 weight percent water after the solvent exchange (e.g., distillation) process.

The reaction mixture includes one or more polymerizable materials that have a polymerizable group that can undergo free radical polymerization (i.e., the polymerizable group is free radical polymerizable). In many embodiments, the polymerizable group is an ethylenically unsaturated group such as a (meth)acryloyl group, which is a group of formula

where R^b is hydrogen or methyl. In some embodiments, the polymerizable group is a vinyl group (-CH=CH2) that is not a (meth)acryloyl group. The polymerizable material is usually selected so that it is soluble in or miscible with the organic solvent having a boiling point equal to at least 150°C.

The polymerizable material includes a first monomer that is a surface modification agent having a free radical polymerizable group. The first monomer typically modifies the surface of the zirconia-based particles. Suitable first monomers have a surface modifying group that can attach to a surface of the zirconia-based particles. The surface modifying group is usually a carboxyl group (-COOH or an anion thereof) or a silyl group of formula -Si(R⁷)x(R⁸)₃-x where R⁷ is a non-hydrolyzable group, R⁸ is hydroxyl or a hydrolyzable group, and the variable x is an integer equal to 0, 1, or 2. Suitable non-hydrolyzable groups are often alkyl groups such as those having 1 to 10, 1 to 6, 1 to 4, or 1 to 2 carbon atoms. Suitable hydrolyzable groups are often a halo (e.g., chloro), acetoxy, alkoxy group having 1 to 10, 1 to 6, 1 to 4, or 1 to 2 carbon atoms, or group of formula

-OR^d-OR^e where R^d is an alkylene having 1 to 4 or 1 to 2 carbon atoms and R^e is an alkyl having 1 to 4 or 1 to 2 carbon atoms.

The first monomer can function as a polymerizable surface modification agent. Multiple first monomers can be used. The first monomer can be the only kind of surface modification agent or can be combined with one or more other non-polymerizable surface modification agents such as those discussed above. In some embodiments, the amount of the first monomer is at least 20 weight percent based on a total weight of polymerizable material. For example, the amount of the first monomer is often at least 25 weight percent, at least 30 weight percent, at least 35 weight percent, or at least 40 weight percent. The amount of the first monomer can be up to 100 percent, up to 90 weight percent, up to 80 weight percent, up to 70 weight percent, up to 60 weight percent, or up to 50 weight percent. Some reaction mixtures contain 20 to 100 weight percent, 20 to 80 weight percent, 20 to 60 weight percent, 20 to 50 weight percent, or 30 to 50 weight percent of the first monomer based on a total weight of polymerizable material.

The first monomer (i.e., the polymerizable surface modification monomer) can be the only monomer in the polymerizable material or can be combined with one or more second monomers that are soluble in the solvent medium. Any suitable second monomer that does not have a surface modification group can be used. That is, the second monomer does not have a carboxyl group or a silyl group. The second monomers are often polar monomers (e.g., non-acidic polar monomers), monomers having a plurality of

polymerizable groups, alkyl (meth)acrylates, and mixtures thereof.

Overall, the polymerizable material typically contains 20 to 100 weight percent first monomer and 0 to 80 weight percent second monomer based on a total weight of polymerizable material. For example, polymerizable material includes 30 to 100 weight percent first monomer and 0 to 70 weight percent second monomer, 30 to 90 weight percent first monomer and 10 to 70 weight percent second monomer, 30 to 80 weight percent first monomer and 20 to 70 weight percent second monomer, 30 to 70 weight percent first monomer and 30 to 70 weight percent second monomer, 40 to 90 weight percent first monomer and 10 to 60 weight percent second monomer, 40 to 80 weight percent first monomer and 20 to 60 weight percent second monomer, 50 to 90 weight percent first monomer and 10 to 50 weight percent second monomer, or 60 to 90 weight percent first monomer and 10 to 40 weight percent second monomer.

In some applications, it can be advantageous to minimize the weight ratio of polymerizable material to zirconia-based particles in the reaction mixture. This tends to reduce the amount of decomposition products of organic material that needs to be burned out prior to formation of the sintered article. The weight ratio of polymerizable material to zirconia-based particles is often at least 0.05, at least 0.08, at least 0.09, at least 0.1, at least 0.11, or at least 0.12. The weight ratio of polymerizable material to zirconia-based particles can be up to 0.80, up to 0.6, up to 0.4, up to 0.3, up to 0.2, or up to 0.1. For example, the ratio can be in a range of 0.05 to 0.8, 0.05 to 0.6, 0.05 to 0.4, 0.05 to 0.2, 0.05 to 0.1, 0.1 to 0.8, 0.1 to 0.4, or 0.1 to 0.3.

The reaction mixture used to form the gel composition contains a photoinitiator. The reaction mixtures advantageously are initiated by application of actinic radiation. That is, the polymerizable material is polymerized using a photoinitiator rather than a thermal initiator. Surprisingly, the use of a photoinitiator rather than a thermal initiator tends to result in a more uniform cure throughout the gel composition ensuring uniform shrinkage in subsequent steps involved in the formation of sintered articles. In addition, the outer surface of the cured part is more uniform and more defect free when a photoinitiator is used rather than a thermal initiator.

Photoinitiated polymerization reactions often lead to shorter curing times and fewer concerns about competing inhibition reactions compared to thermally initiated polymerization reactions. The curing times can be more easily controlled than with thermal initiated polymerization reactions that must be used with opaque reaction mixtures.

In most embodiments, the photoinitators are selected to respond to ultraviolet and/or visible radiation. Stated differently, the photoinitiators usually absorb light in a wavelength range of 200 to 600 nanometers, 300 to 600 nanometers, or 300 to 450 nanometers. Some exemplary photoinitiators are benzoin ethers (e.g., benzoin methyl ether or benzoin isopropyl ether) or substituted benzoin ethers (e.g., anisoin methyl ether). Other exemplary photoinitiators are substituted acetophenones such as 2,2- diethoxyacetophenone or 2,2-dimethoxy-2-phenylacetophenone (commercially available under the trade designation IRGACURE 651 from BASF Corp. (Florham Park, NJ, USA) or under the trade designation ESACURE KB-1 from Sartomer (Exton, PA, USA)). Other exemplary photoinitiators are substituted benzophenones such as 1 -hydroxy cyclohexyl benzophenone (available, for example, under the trade designation "IRGACURE 184" from Ciba Specialty Chemicals Corp., Tarrytown, NY). Still other exemplary

photoinitiators are substituted alpha-ketols such as 2-methyl-2-hydroxypropiophenone, aromatic sulfonyl chlorides such as 2-naphthalenesulfonyl chloride, and photoactive oximes such as 1 -phenyl- l,2-propanedione-2-(0-ethoxycarbonyl)oxime. Other suitable photoinitiators include camphoquinone, 1 -hydroxy cyclohexyl phenyl ketone (IRGACURE 184), bis(2,4,6-trimethylbenzoyl)phenylphosphineoxide (IRGACURE 819), l-[4-(2- hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-l -propane- 1 -one (IRGACURE 2959), 2- benzyl-2-dimethylamino-l-(4-mo holinophenyl)butanone (IRGACURE 369), 2-methyl- l-[4-(methylthio)phenyl]-2-mo holinopropan-l-one (IRGACURE 907), and 2-hydroxy- 2-methyl-l -phenyl propan-l-one (DAROCUR 1173).

The photoinitiator is typically present in an amount in the range of 0.01 to 5 weight percent, in the range of 0.01 to 3 weight percent, 0.01 to 1 weight percent, or 0.01 to 0.5 weight percent based on a total weight of polymerizable material in the reaction mixture.

Pillars may be monolithic or composite. Composite pillars may comprise a high compressive strength sintered ceramic core and one or more functional layers.

Alternately, composite pillars may comprise a thermally stable organic, inorganic, or hybrid polymeric binder and an inorganic nanoparticle filler.

The pillar body can be fabricated by a molding process. The shape of the body is determined by the mold cavity used. The mold cavity, generally, having the inverse shape corresponding to and dimensions of the desired pillar body shape. If desired, rounded and/or chamfered corners and rounded and/or chamfered edges may be included in the mold cavity (inverse shape), such that, the rounded and/or chamfered corners and rounded and/or chamfered edges may be integrally in the pillar body, when the body is formed. The at least one first structure and/or at least one second structure (inverse shape) may be included in the corresponding region of the mold and the at least one first structure and/or at least one second structure may be integrally formed in the pillar body, when the body is formed. One or more channels may be integrally formed using the same approach. Monolithic pillar bodies can be made via continuous and discontinuous processes. One such process is a sol gel process. Sol gel processes are disclosed in pending U.S. Appl. No. 14/025958, titled "VACUUM GLAZING PILL ARS FOR INSULATED GLASS UNITS", filed September, 13, 2013 and pending U.S. Provisional Appl. No. 62/127569, titled GEL COMPOSITIONS AND SINTERED ARTICLES PREPARED

THEREFROM", filed March, 3, 2015, which has been incorporated herein in its entirety by reference. This process involves molding of gel bodies from a reaction mixture on a continuous belt, drying, demolding, and sintering. This process may yield bodies with some asymmetry. Surfaces in contact with the mold during the fabrication side may be smoother than the surface with an air interface. In addition, samples may warp or cup slightly during drying to form a pillar with a concave air side and a convex mold side. Using higher solids content sols and slower drying processes results in reduced cupping due to drying shrinkage. The materials and process parameters are optimized to compensate for the differential shrinkage as well as to keep the pillars flat. Optimal conditions for producing sol -gel pillar bodies may produce discrete pillars that are suitable for use in vacuum insulated glazing without further modification.

A modified sol-gel process involving densification of an aerogel intermediate has been shown to greatly improve fidelity and minimize cupping or distortion during the drying process.

In an optional step, it may be desired to introduce a modifying additive by an impregnation process. A water-soluble salt can be introduced by impregnation into the pores of the calcined, pillar bodies. Then the pillar bodies are prefired again. This option is further described in European Patent Application Publication No. 293,163. The pillar bodies were calcined at approximately 650 degrees Celsius and then saturated with a mixed nitrate solution of the following concentration (reported as oxides): 1.8% each of MgO, Y2O3, Nd₂0₃ and La₂0₃. The excess nitrate solution was removed and the saturated pillar bodies with openings were allowed to dry after which the pillar bodies were again calcined at 650 degrees Celsius and sintered at approximately 1400 degrees Celsius. Both the calcining and sintering was performed using rotary tube kilns.

In one embodiment, a method of making a pillar body includes (a) providing a mold having a mold cavity, wherein the mold cavity includes the inverse shape corresponding to at least one of a chamfered peripheral edge and a rounded peripheral edge (b) positioning a reaction mixture within the mold cavity, (c) polymerizing the reaction mixture to form a shaped gel body that is in contact with the mold cavity, (d) removing the shaped gel body from the mold cavity, wherein the shaped gel body retains a size and shape identical to the mold cavity, (e) forming a dried shaped gel body by removing the solvent medium, (f) heating the dried shaped gel body to form a sintered body. The sintered body has a shape identical to the mold cavity including at least one of a chamfered peripheral edge and a rounded peripheral edge but may be reduced in size proportional to an amount of shrinkage. The reaction mixture may be as described above. The dimensions of the mold cavity may be adjusted to account for the shrinkage.

In some embodiments, the pillar body may be a polymer composite, including a binder, i.e. a polymer binder. The binder may be based on thermally stable organic, inorganic, or hybrid polymers. These materials are typically dimensionally stable upon exposures to temperatures up to 350 °C. Preferably, the binder material has a low thermal conductivity, which would reduce the transfer of heat from the exterior through to the interior window pane.

Thermally stable binders include, but are not limited to, at least one of: polyimide, polyamide, polyphenylene, polyphenylene oxide, polyaramide (e.g., the KEVLAR product from Dupont), polysulfone, polysulfide, polybenzimidazoles, and polycarbonate. One exemplary binder that may be used is the ULTEM product (polyetherimide) manufactured by SABIC Innovative Plastics. Another exemplary binder is an imide-extended

bismaleimide such as BMI-1700, available from Designer Molecules (San Diego, CA), which can be melt-processed at low temperatures and then cured to form a crosslinked polyimide network.

The polymer binder may include thermally stable inorganic, siloxane, or hybrid polymeric species. These materials are typically dimensionally stable upon exposures to temperatures up to 350 °C. Amorphous organopolysiloxane networks, a chemical bond network derived from condensation of organosiloxane precursors, is an example of a suitable thermally stable polymeric binder. Silsesquioxanes or polysilsesquioxanes are derived from fundamental molecular units that have silicon coordinated with three bridging oxygen atoms. Because of this, silsesquoxanes can form a wide variety of complex three-dimensional shapes. Various polysilsesquioxanes can be used, for example, polymethylsilsesquioxane, polyoctylsilsesquioxane, polyphenylsilsesquioxane and polyvinylsilsesquioxane. Suitable specific polysilsesquioxanes include, but are not limited to, acrylopoly oligomeric silsesquioxane (Catalog # MA0736) from Hybrid Plastics of Hattiesburg, Mississippi; polymethylsilsesquioxane from Techneglas of Columbus, Ohio and sold under the label GR653L, GR654L, and GR650F; polyphenylsilsesquioxane from Techneglas of Columbus, Ohio and sold under the label GR950F; and

polymethylphenylsilsesquioxane from Techneglas of Columbus, Ohio and sold under the label GR908F.

The polymer binder may also comprise other alkoxysilanes, such as

tetraalkoxysilanes and alkyltrialkoxysilanes having the formula: (R')x Si~(OR2)y wherein R may be an alkyl, alkylaryl, arylalkyl, aryl, alcohol, polyglycol, or poly ether group, or a combination or mixture thereof; R2 may be an alkyl, acetoxy, or a methoxyethoxygroup, or a mixture thereof, x=from 0 to 3 and y=from 4 to 1 respectively, with the proviso that x+y=4. The one or more alkoxysilanes including mono-, di-, tri-, and tetraalkoxysilanes may be added to control the crosslink density of the organosiloxane network and control the physical properties of the organosiloxane network including flexibility and adhesion promotion. Examples of such alkoxysilanes include, but are not limited to,

tetraethoxysilane, tetramethoxysilane, methyltriethoxysilane, and methyltrimethoxysilane. Such ingredients may be present in an amount of about 0 to 50 weight percent.

The polymer composite includes nanoparticles. The nanoparticles may include silica, zirconia, titania, alumina, clay, metals, or other inorganic materials. The loading of the nanoparticles is typically greater than 50 vol%.

Polymer composite pillars based on nanoparticle filled polymers can be formed by casting a paste into a mold, the mold cavity having the inverse shape and corresponding dimensions of the desired pillar body. This type of mold may be referred to as a negative master. The pastes comprise a thermal or radiation curable composite binder formulation and inorganic nanoparticles. The paste can then be cured using the appropriate form of radiation, yielding solid, polymer composite pillar bodies. When removed from the mold cavity, the pillar bodies have the inverse shape of the mold cavity from which they were formed. A plurality of structures or at least one channel can be included in the body by including the inverse shape of the plurality of structures or at least one channel in the surface of the mold corresponding to the first contact surface or second contact surface of the pillar body. In some embodiments, the body may further include a functional layer on at least a portion of the body. Functional layers or coating may be added as a layer or an

enveloping coating around a pillar body. Functional coatings have been disclosed in pending U.S. Appl. No. 14/025958, titled "VACUUM GLAZING PILL ARS FOR

INSULATED GLASS UNITS", filed September, 13, 2013, which has been incorporated herein by reference in its entirety. The functional layer may include at least one of a compliant layer comprising a thermally stable polymer, a compliant layer comprising inorganic nanoparticles, a ferromagnetic layer, an electrically conductive layer, a statically dissipative layer and an adhesive; and optionally, wherein the adhesive comprises a sacrificial material.

A compliant planarization layer is one example of a functional layer that may be coated as a layer or an enveloping coating around a pillar body, e.g. a sintered ceramic pillar body, and is a thermally stable crosslinked nanocomposite that serves to flatten and smooth one or both of the major pillar body surfaces. The planarization layer may also allow for a slight compression of the pillar during the fabrication of an insulated glass unit and thus reduce the likelihood of glass crack initiation or propagation upon evacuation to reduced pressure or to other environmental impacts. The planarization layer comprises an organic, inorganic, or hybrid polymeric binder and an optional inorganic nanoparticle filler The polymeric binder may include thermally stable organic polymeric species. These materials are typically dimensionally stable upon exposures to temperatures up to 350 °C. Preferably, the binder material has a low thermal conductivity, which would reduce the transfer of heat from the exterior through to the interior window pane.

Thermally stable organic polymeric component may be selected from thermally stable binders, thermally stable inorganic, siloxane, or hybrid polymeric species previously described.

A planarizing process for composite pillars can be carried out by thermal or radiation curing of the planarization material on one or both major surfaces of a pillar body while it is between two flat surfaces. The composition may be identical to that of the composite pillars. The planarization layer can have either adhesive or lubricant characteristic.

The compliant adhesive layer comprises a thermal or radiation sensitive silsesquioxane, a photoinitiator, and a nanoparticle filler. The material can be crosslinked photochemically and then heated to initiate condensation of the silanol groups of the silsesquioxane, forming a durable, thermally stable material. In addition to providing adhesion between the pillar and one of the glass panes, the adhesive layer can be used to set the final pillar height and define (minimize) the pillar height variation.

The orientation layer is a material applied to a pillar body while it is still in the mold. The orientation can be on the mold side or the air side. The air side is the exposed surface of the pillar when it is in the mold. The function of the orientation layer is to physically or chemically differentiate the mold and air sides during placement of the pillars on a surface. The orientation layer can be electrically conductive or statically dissipative, ferromagnetic, ionic, hydrophobic, or hydrophilic.

The frit glass coating is a dispersion of low melting glass microparticles in a sacrificial binder that is applied uniformly to the exterior of the pillar body. During the vacuum insulated glass unit assembly process, the sacrificial binder is thermally decomposed and the frit glass flows to form an adhesive bond to one or both of the glass panes. Sacrificial polymers such as, for example, nitrocellulose, ethyl cellulose, alkylene polycarbonates, [methjacrylates, and polynorbonenes can be used as binders.

The low COF layer may be a thermally stable material that promotes slip between the pillar body and a flat surface (e.g., one of the inner glass surfaces in a vacuum insulated glass unit). The layer may comprise a monolayer of fluorosilanes, a fluorinated nanoparticle filled polyimide (e.g., Corin XLS, NeXolve, Huntsville, AL), a thin coating of a low surface energy polymer (e.g., PVDF or PTFE), a diamond-like carbon (DLC) layer, or a lamellar layer comprising graphite, or other thermally stable lubricant materials.

In another embodiment, the present disclosure includes a vacuum insulated glass unit having pillars, comprising: a first glass pane; a second glass pane opposite and substantially co-extensive with the first glass pane; an edge seal between the first and second glass panes with a substantial vacuum gap between the first and second glass panes; and a plurality of pillars, according to any one of the previously described pillar embodiments of the present disclosure, disposed between the first and second glass panes. The use of pillars in IGUs is known in the arts and the pillars of the present disclosure can be included in an IGU using conventional techniques. A vacuum insulated glass unit 400 is shown in FIGS. 8A and 8B. Unit 400 includes two panes of glass 411 and 412 separated by a vacuum gap. Pillars 414 in the gap maintain the separation of glass panes 411 and 412, which are hermetically sealed together by an edge seal 413, which may be a low melting point glass frit.

Examples

Vacuum glazing pillar articles were prepared by using sol casting and molding methods with organic burnout and sintering processes. The resultant constructions, as shown in the following examples, provide pillars with reduced surface area that allow evacuation of air from the pillar interior and prevent interlacing of the pillars during bulk processing.

These examples are merely for illustrative purposes only and are not meant to be limiting on the scope of the appended claims. All parts, percentages, ratios, etc. in the examples and the rest of the specification are by weight, unless noted otherwise. Solvents and other reagents used were obtained from Sigma-Aldrich Chemical Company, St. Louis, Missouri unless otherwise noted.

Materials:

Ethanol KOPTEC 200 proof ethanol obtained from DLI, King of

Prussia, PA, USA.

Acrylic acid Acrylic acid obtained from Alfa Aesar, Ward Hill, MA, USA.

"SR506" Isobornyl acrylate, obtained from Sartomer Company, Inc.

Exton, PA, USA under the trade designation "SR506".

"SR238" 1,6-Hexanediol diacrylate, obtained from Sartomer Company,

Inc. Exton, PA, USA under the trade designation "SR238".

"CN975" Hexafunctional aromatic urethane acrylate oligomer, obtained from Sartomer Company, Inc. Exton, PA, USA under the trade designation "CN975".

Polypropylene sheet Polypropylene sheet 1/16" thick, obtained from McMaster Carr,

Elmhurst, IL, USA as catalog number 8742K131

Preparation of ZrQ₂ (88 mol %) /Y2O3 (12 mol %) Sol batch

Sol compositions are reported in mole percent inorganic oxide. The following hydrothermal reactor was used for preparing the Sol. The hydrothermal reactor was prepared from 15 meters of stainless steel braided smooth tube hose (0.64 cm inside diameter, 0.17 cm thick wall; obtained under the trade designation "DUPONT T62 CHEMFLUOR PTFE" from Saint-Gobain Performance Plastics, Beaverton, MI). This tube was immersed in a bath of peanut oil heated to the desired temperature. Following the reactor tube, a coil of an additional 3 meters of stainless steel braided smooth tube hose ("DUPONT T62 CHEMFLUOR PTFE"; 0.64 cm I D., 0.17 cm thick wall) plus 3 meters of 0.64 cm stainless-steel tubing with a diameter of 0.64 cm and wall thickness of 0.089 cm that was immersed in an ice-water bath to cool the material and a backpressure regulator valve was used to maintain an exit pressure of 3.45 MPa.

A precursor solution was prepared by combining the zirconium acetate solution (6,200 grams) with DI water (2074.26 grams). Yttrium acetate (992.62 grams) was added while mixing until fully dissolved. The solids content of the resulting solution was measured gravimetrically (120°C/hr. forced air oven) to be 22.30 wt. %. D.I. water (2,289 grams) was added to adjust the final concentration to 19 wt. %. The resulting solution was pumped at a rate of 11.48 ml/min. through the hydrothermal reactor. The temperature was 225°C and the average residence time was 42 minutes. A clear and stable zirconia sol was obtained. Sol Concentration

The resulting sol was concentrated (35- 45 wt. % solids) via ultrafiltration and further diafiltered using a membrane cartridge (obtained under the trade designation "M21 S-100-01P" from Spectrum Laboratories Inc., Rancho Dominguez, CA). The final sol composition was 34.68 wt. % oxide and 3.70 wt.% acetic acid.

Master Tool Preparation Procedure for Example 1 : 4-lobe shaped pillar

A master tool with a structure similar to that of the 4-lobed shaped pillar shown in FIGS. 9A and 9b, with dimensions of 1000 microns across (outer diameter), a thickness of 400 microns, and a first structure thickness of about 10 microns, was formed using the 2- photon lithography fabrication method described in U.S. Pat. Publ. No. US2009/0099537 (DeVoe et al.), which is incorporated herein by reference in its entirety. The master array was then electroformed with nickel (2.5 mm thick) according to the procedure described in Example 6 of DeVoe et al. to create the inverse (or negative) form of the master. This inverse form was then used as the template for a second nickel plating, about 0.60 mm thick, which inverted the structure again. This electroplated part was processed in a machine shop to grind the backside flat and produced a tool with final thickness of 0.520 mm and that had the same structure as the original 2-photon master array.

Polymer Tool Preparation Procedure

A polypropylene tool was generated from the master tool. A 0.0625 inch thick (0.159 cm) sheet of polypropylene (available from McMaster Carr, Elmhurst, IL, USA) was placed on top of the master tool and embossed for 20 minutes at 383°F (195°C) and 6 psi using a stainless steel platen and the appropriate amount of weight to generate 6 psi pressure. The pressure was released by removing the weights and temperature was reduced to 75°F (24°C) and the polypropylene polymer tool was separated from the master tool. Then, the polypropylene tool was annealed between 2 glass plates at 248°F (120°C) for 20 mins. Example 1 - Micro-molded, structured, 4-lobe shaped pillars

Preparation of Ζ1Ό2 (97.7 mol %) /Y2O3 (2.3 mol %) Soil

A precursor solution was prepared and processed similar to the sol batch preparation procedure described above except that the composition of the sol was ZrCh (97.7 mol %) /Y2O3 (2.3 mol %) Sol.

Sol Concentration

The sol composition after processing via one or more of ultrafiltration, diafiltration and distillation was 40.84 wt. % oxide and 4.00 wt.% acetic acid.

Preparation of Casting Sol2

The above sol (645.62 grams), MEEAA (9.41 grams), and di ethylene glycol monoethyl ether (135.64 grams) were charged to a 1000 ml RB flask. The sample weight was reduced via rotary evaporation to yield a concentrated sol (438.76 grams, 60.09 wt. % oxide). The concentrated sol (437.40 grams) was charged to ajar and combined with diethylene glycol monoethyl ether (26.32 grams), MEEAA (4.68 grams), acrylic acid (27.03 grams), isobornyl acrylate ("SR506") (24.64 grams), 1,6-hexanediol diacrylate ("SR238") (10.11 grams), and a hexafunctional urethane acrylate ("CN975") (18.23 grams). IRGACURE 819 (2.34 grams) was dissolved in ethanol (86.98 grams) and charged to the sol. The sol was passed through a 1 micron filter.

Sol Casting of Casting Sol2

Casting Sol2 was cast into a polypropylene tool containing structured, 4-lobed shapes with dimension of about 1000 microns across by 400 microns deep. The mold was adhered to a 2" x 3" (5 cm x 7.5 cm) glass plate with doubled sided tape. The sol was flood coated onto the tool using a pipette. A PET film was then carefully placed over the filled tool to prevent significant void formation. A 2" x 3" (5 cm x 7.5 cm) glass plate was then placed on top of the PET, pressure was applied by hand to remove excess sol and the construction was clamped together. The sol was cured for 2 minutes using a 380 - 401 nm LED light source at 100% power (CF2000 rev. 3.0 available from Clearstone

Technologies Hopkins, MN, USA). The cured parts were removed from the tool by removing the clamps, the top glass plate and the PET film and applying a 0.5 inch (1.27 mm) diameter tip of an ultrasonic horn (Sonifer Cell disrupter, available from Branson Ultrasonics, Danbury, CT, USA) to the backside of the polypropylene tool with the equipment set at continuous and the output set at 2 on the analog dial. The parts were allowed to drop onto a nylon mesh screen. This allowed the 4-lobe shaped pillars to dry equally from all sides at room temperature for up to 24 hours. The dried 4-lobe shaped xerogels were then burned out and sintered as follows:

Organic burnout and sinter process

The dried pillars are placed in an alumina crucible, then heated in air according to the following schedule:

Organic burnout process:

1- Heat from 20°C to 220°C at 18°C/hr rate,

2- Heat from 220°C to 244°C at l°C/hr rate,

3- Heat from 244°C to 400°C at 6°C/hr rate,

4- Heat from 400°C to 1020°C at 60°C/hr rate,

5- Cool from 120°C to 20°C at 120°C/hr rate.

Sinter process:

1 - Heat from 20°C to 1020°C at 600°C/hr rate,

2- Heat from 1020°C to 1320°C at 120°C/hr rate,

3- Hold at 1320°C for 2 hr,

4- Cool from 1320°C to 20°C at 600°C/hr rate. The resulting 4-lobe shaped pillar of Example 1 is shown in the SEM images of

FIG. 9A (top view) and FIG. 9B (perspective view). The pillars made in this Example had a plurality of first structures on the top surface only.

Claims

What is claimed:

A pillar for use in a vacuum insulated glass unit comprising:

a body comprising:

a hub region; and

a plurality of arms radiating from and integral with the hub region, each arm comprising a neck and a lobe, the neck connecting the lobe to the hub region; wherein the body has a thickness, Tb, a first contact surface with first area Abl, an opposed second contact surface with a second surface area, Ab2 and at least one sidewall, wherein the first contact surface comprises at least one first structure integral with the contact surface, the at least one first structure having a first structure base and a first structure face opposite the base, a thickness Tsl and a first structure face surface area, Asl .

The pillar for use in a vacuum insulated glass unit of claim 1, wherein the thickness, Tb, is between about 10 micron and about 2000 microns.

The pillar for use in a vacuum insulated glass unit of claim 1, wherein the ratio of Tsl/Tb is between about 0.01 and about 0.6.

The pillar for use in a vacuum insulated glass unit of claim 1, wherein Asl/Abl is between about 0.03 and about 0.95.

The pillar for use in a vacuum insulated glass unit of claim 1, wherein the largest dimension, Ld, of the body parallel to the first contact surface is between about 10 microns and about 2000 microns.

The pillar for use in a vacuum insulated glass unit of claim 1, wherein the at least one first structure is a plurality of first structures, each of the individual first structures of the plurality of first structures has a first structure face opposite its base, each individual first structure face having a surface area asl and wherein the first structure face surface area, Asl, is the sum of the first structure face surface area, asl, of each individual first structure of the plurality of first structures.

7. The pillar for use in a vacuum insulated glass unit of claim 1, wherein the opposed second contact surface of the body may further comprise at least one second structure having a second structure base and a second structure face opposite the base, a thickness Ts2 and a second structure face surface area, As2.

8. The pillar for use in a vacuum insulated glass unit of claim 7, wherein the at least one second structure is integral with the second contact surface.

9. The pillar for use in a vacuum insulated glass unit of claim 8, wherein the ratio of Ts2/Tb is between about 0.01 and 0.6.

10. The pillar for use in a vacuum insulated glass unit of claim 7, wherein the ratio of As2/Ab2 is between about 0.03 and about 0.95.

11. The pillar for use in a vacuum insulated glass unit of claim 7, wherein the at least one second structure may be a plurality of second structures, each of the individual second structures of the plurality of second structures has a second structure face opposite its base, each individual second structure face having a surface area as2, and wherein the second structure face surface area, As2, is the sum of the second structure face surface area, as2, of each individual second structure of the plurality of second structures.

12. The pillar for use in a vacuum insulated glass unit of claim 1, wherein the first contact surface of the pillar body includes at least one channel and wherein the thickness of the at least one channel is greater than that of the thickness of the at least one first structure.

13. The pillar for use in a vacuum insulated glass unit of claim 1, wherein at least a portion of a first peripheral edge adjoining the first contact surface and the at least one sidewall is at least one of a rounded peripheral edge and chamfered peripheral edge.

14. The pillar for use in a vacuum insulated glass unit of claim 1, wherein at least a portion of a second peripheral edge adjoining the second contact surface and the at least one sidewall is at least one of a rounded peripheral edge and chamfered peripheral edge.

15. A vacuum insulated glass unit comprising:

a first glass pane;

a second glass pane opposite and substantially co-extensive with the first glass pane;

an edge seal between the first and second glass panes with a substantial vacuum gap between the first and second glass panes; and

a plurality of pillars according to claim 1 disposed between the first and second glass panes.