TWI641477B - Composite material and method of manufacturing the same - Google Patents

Abstract

The present invention provides a composite material. The composite material includes a nanocellulose inner core and a metal outer casing. The metal casing covers the surface of the inner core of the nanocellulose. The above composite material has a nanometer size and high mechanical strength. In addition, the present invention also provides a method of manufacturing a composite material.

Description

Composite material and method of manufacturing same

The present invention relates to a material and a method of manufacturing the same, and more particularly to a composite material and a method of manufacturing the same.

With the rapid development of technology, printing technology has also been upgraded. Among them, printed electronics technology and its various aspects, including nanowires, electrodes, and transparent conducting films. Production.

However, the conductive ink used for printing electrons is usually made of nano metal particles or nano metal foil, and less one-dimensional nano metal material exists, because the diameter of the one-dimensional nano metal material is about several tens of nanometers. The length is about a few microns. The size of this metal material is too large and may cause problems with nozzle clogging during printing. On the other hand, in the prior art, in order to form a conductive ink having a small-sized metal material, it is necessary to first form a microporous channel in the aluminum oxide layer, and then, after filling the metal material by electrochemical deposition, move it again. In addition to the alumina layer template, the steps in the process are more complicated. In addition, one of the conventional techniques is often broken into fragments or melted into particles due to an increase in temperature, losing its original appearance, causing electrical changes and reducing electrical conductivity. Therefore, how to improve the problem of nozzle clogging and simplify the process and maintain electrical properties is the subject of current research.

The present invention provides a composite material having a nanometer size and high mechanical strength.

The present invention provides a method of producing a composite material by which a composite material having a nanometer size and high mechanical strength can be produced.

The present invention provides a composite material comprising a nanocellulose inner core and a metal outer shell. The metal casing covers the surface of the inner core of the nanocellulose.

In some embodiments of the invention, the composite has a length to diameter ratio of between 1.5:1 and 500:1.

In some embodiments of the invention, the composite material has a diameter between 2 nanometers and 200 nanometers.

In some embodiments of the invention, the composite has a length between 50 nanometers and 5000 nanometers.

In some embodiments of the present invention, the material of the nanocellulose core comprises cellulose nanofibrils (CNF), cellulose nanocrystals (CNC), and bacterial cellulose. , BC) or a combination thereof.

In some embodiments of the invention, the nanocellulose core is solid.

In some embodiments of the invention, the nanocellulose core has a diameter between 2 nanometers and 200 nanometers.

In some embodiments of the invention, the material of the metal outer casing comprises gold, silver, palladium, platinum, rhodium, copper, tungsten, nickel, aluminum, or a combination thereof.

In some embodiments of the invention, the metal outer shell has a thickness between 2 nanometers and 200 nanometers.

The invention provides a method for manufacturing a composite material, the method for manufacturing the composite material comprising the steps of: providing a nanocellulose inner core; modifying a nanocellulose inner core; and forming a metal seed to form a metal ion at the modified point a surface of the inner core of the nanocellulose; performing a first reduction reaction to reduce metal ions at a point of formation of the metal seed crystal to form a metal seed crystal; and performing a second reduction reaction to reduce the metal of the metal seed crystal formation point at the metal seed crystal The ions are coated with a metal shell to coat the surface of the modified nanocellulose core.

In some embodiments of the invention, the step of modifying the inner core of the nanocellulose is a metal substitution reaction of a hydroxyl group on the carbon of the inner core of the nanocellulose to form a metal-substituted hydroxyl group.

In some embodiments of the invention, the metal ions at the point of formation of the metal seed are formed on a metal-substituted hydroxyl group.

In some embodiments of the invention, the step of modifying the nanocellulose core comprises subjecting the nanocellulose core to a substitution reaction with potassium hydroxide, sodium hydroxide.

In some embodiments of the invention, the reducing agent that performs the first reduction reaction and the second reduction reaction includes ascorbic acid, hydrazine, sodium borohydride, formaldehyde, glucose, sodium citrate. Urea, diethanolamine, triethanolamine, methanol, ethanol, ethylene glycol, glycerol or a combination thereof.

In some embodiments of the present invention, the metal ions forming the metal seed generation point and the metal precursor for performing the second reduction reaction include silver nitrate, silver nitrite, silver sulfate, silver chloride, silver perchlorate, and silver cyanate. , silver carbonate, silver acetate, gold sulfite, chloroauric acid, chloroplatinic acid, copper nitrate, copper sulfate, copper chloride, nickel sulfate or a combination thereof.

In some embodiments of the invention, performing the second reduction reaction further comprises adding a polymer.

In some embodiments of the invention, the polymer comprises polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polyacrylic acid (PAA), or a combination thereof.

In some embodiments of the invention, the reaction temperature at which the first reduction reaction and the second reduction reaction are carried out is between 0 degrees Celsius and 250 degrees Celsius.

In some embodiments of the invention, the material of the metal outer casing comprises gold, silver, palladium, platinum, rhodium, copper, tungsten, nickel, aluminum, or a combination thereof.

Based on the above, the composite material of the present invention comprises a nanocellulose inner core and a metal outer shell, wherein the metal outer shell covers the surface of the inner core of the nanocellulose. From the structural point of view, the size of the composite material of the present invention can be controlled within the range of nanometer size, so that the problem of clogging due to excessive size can be effectively reduced. Further, in the composite material of the present invention, since nano cellulose is used as the inner core, it has high crystallinity, so that the mechanical strength of the entire composite material can be improved. And the inner core of nano cellulose can be used as a supporting template to prevent metal melting from affecting electrical properties. From the viewpoint of the process, in the manufacturing process of the composite material of the present invention, the metal outer shell is defined by the inner core of the nano cellulose, and the subsequent step of removing the inner core of the nano cellulose is not required, so that the process is simplified.

The above described features and advantages of the invention will be apparent from the following description.

1 is a schematic illustration of a composite material in accordance with some embodiments of the present invention.

Referring to FIG. 1 , the composite material 100 of the present embodiment may include a nano cellulose inner core 110 and a metal outer casing 120 . The metal casing 120 covers the surface of the nanocellulose core 110.

<Nano cellulose core>

The material of the nano cellulose core 110 includes, for example, cellulose nanofibrils (CNF) derived from plants, algae or bacteria, cellulose nanocrystals (CNC), bacterial cellulose (bacterial cellulose, BC) or a combination thereof. In some embodiments, the material of the nanocellulose core 110 is, for example, crystalline cellulose. In some embodiments, the molecular weight of the nanocellulose core 110 is, for example, between 500 and 500,000. In some embodiments, the diameter of the nanocellulose core 110 is, for example, between 2 nanometers and 200 nanometers. In other embodiments, the nanocellulose core 110 has a diameter of, for example, less than 5 nanometers. In some embodiments, the length of the nanocellulose core 110 is, for example, between 20 nanometers and 20,000 nanometers. In some embodiments, the ratio of length to diameter of the nanocellulose core 110 is, for example, between 10:1 and 1000:1. In other embodiments, the ratio of length to diameter of the nanocellulose core 110 is, for example, 60:1, although the invention is not limited thereto. The chemical formula of cellulose is as follows:

<metal casing>

The material of the metal casing 120 includes, for example, a precious metal. In some embodiments, the material of the metal outer casing 120 includes, for example, gold, silver, palladium, platinum, rhodium, copper, tungsten, nickel, aluminum, or a combination thereof. In some embodiments, the thickness of the metal outer casing 120 is, for example, between 2 nanometers and 200 nanometers.

<composite material>

In some embodiments, the nanocomposite core 110 and the metal shell 120 form a composite 100 having a diameter of, for example, between 2 nm and 200 nm. In some embodiments, the length of the composite material 100 is, for example, between 50 nanometers and 5000 nanometers. In some embodiments, the ratio of length to diameter of composite 100 is, for example, between 1.5:1 and 500:1. In other embodiments, the ratio of length to width of composite 100 is, for example, 60:1, although the invention is not limited thereto.

In some embodiments, the nanocellulose core 110 can be solid. That is, since the nanocellulose core 110 is solid, the integral composite 100 can have a rigid structure. It is worth mentioning that since the surface of the composite material 100 is covered by the metal outer casing 120, the overall composite material 100 can have electrically conductive characteristics.

2A-2E are schematic views showing a manufacturing process of a composite material according to some embodiments of the present invention. 3A to 3E are schematic diagrams showing the surface chemical structures of the composite materials of Figs. 2A to 2E, respectively. 4 is a schematic flow chart of a method of manufacturing a composite material according to some embodiments of the present invention.

2A to 2E, 3A to 3E, and 3, the manufacturing method of the composite material 100 of the present invention includes: providing a nanocellulose core 110a (step S10); and modifying the nanocellulose core 110a ( Step S12); forming a metal seed formation point metal ion 120a on the surface 112b of the modified nanocellulose inner core 110b (step S14); performing a first reduction reaction to reduce the metal ion generation point metal ion 120a to Forming a metal seed crystal 120b (step S16); and performing a second reduction reaction to reduce the metal ion 120b at the metal seed crystal formation point at the metal seed crystal to form a surface of the nano-cell core coated with the metal outer shell 120 (Step S18). The above steps will be explained in more detail below.

<Step S10>

Referring to FIG. 2A, FIG. 3A and FIG. 4, first, step S10 is performed to provide a nanocellulose core 110a. In some embodiments, the method of forming the nanocellulose core 110a includes, for example, physical methods, chemical methods, or a combination thereof. For example, in some embodiments, the method of forming the nanocellulose core 110a is, for example, physically treated first, followed by chemical treatment to obtain a nanocrystalline core 110a having a high degree of crystallization. In some embodiments, the physical method includes, for example, a treatment using a grinder, a homogenizer, a microfluidizer, or the like; the chemical method is, for example, a single-step or multi-step hydrolysis reaction, such as sulfuric acid hydrolysis. Or hydrochloric acid hydrolysis. The diameter, length, material and the like of the nanocellulose core 110a are as described above for the nanocellulose core 110, and will not be described herein. After the hydrolysis reaction, the nanocellulose core 110a has a hydroxyl group on the carbon. In a specific embodiment, after the hydrolysis reaction of the nanocellulose core 110a, the hydroxyl group (-OH) of the carbon (C6) at the 6-position is, for example, a primary hydroxyl group (-CH ₂ OH). That is, the surface 112a of the nanocellulose core 110a has a plurality of carbon (C6) hydroxyl groups (represented by C6-OH) at the 6 position of the inner core of the nanocellulose for subsequent reaction, but The invention is not limited to this. Here, for convenience of explanation, the hydroxyl group of carbon at the 6-position of the nanocellulose core 110a is exemplified, but the present invention is not limited thereto.

<Step S12>

Referring to FIG. 2B, FIG. 3B and FIG. 4, step S12 is performed to modify the nanocellulose core 110a. In some embodiments, the method of modifying the nanocellulose core 110a is, for example, treating a solution of a metal hydroxide (M(OH) _n , wherein M is a metal, such as K, n is the valence of the metal) solution. The surface 112a of the rice cellulose inner core 110a is substituted with a metal (M) of a metal hydroxide (C6-OH) at the 6-position to form an OM group. That is, the surface 112b of the modified nanocellulose core 110b has an OM group, and the OM group is attached to the carbon (C6) at the 6 position of the modified nanocellulose core 110b ( Represented by C6-OM). The OM group is for example OK.

In some embodiments, the metal hydroxide (M(OH) _n includes, for example, potassium hydroxide (KOH). In a specific embodiment, the modified nanocellulose core 110a is treated, for example, with potassium hydroxide. The surface 112a of the cellulose inner core 110a is substituted with a hydroxyl group (C6-OH) of carbon at the 6-position to an OK group, but the invention is not limited thereto. In some embodiments, the modified nanocellulose core 110a is modified. The substitution reaction of all the hydroxyl groups of the nanocellulose core 110a is not performed, that is, only the hydroxyl group of the partial nanocellulose core 110a is substituted to form an OM group, but the present invention is not limited thereto.

<Step S14>

Referring to FIGS. 2C, 3C and 4, step S14 is performed to form metal ions 120a at the metal seed generation point on the surface 112b of the modified nanocellulose core 110b. In some embodiments, when the surface 112b of the modified nanocellulose core 110b has an OM group, the surface of the modified nanocellulose core 110b may be treated with a solution containing a metal precursor (M'). 112b, the OM group of its surface 112b is replaced with an OM' group. That is, at this time, the surface 112c of the nanocellulose core 110c has an OM' group, and the OM' group is attached to the carbon (C6) at the 6 position of the nanocellulose core 110c ( C6-OM' stands for), this OM' group can be used as a source of metal ions for the generation point of subsequent metal seed growth. The OM' group is, for example, OAg.

In some exemplary embodiments, M is, for example, potassium (K), and M' is, for example, silver (Ag). In some embodiments, the solution containing the metal precursor M' includes, for example, silver nitrate (AgNO ₃ ), silver nitrite (AgNO ₂ ), silver sulfate (Ag ₂ SO ₄ ), silver chloride (AgCl), silver perchlorate. (AgClO ₄ ), silver cyanate (AgOCN), silver carbonate (Ag ₂ CO ₃ ), silver acetate (AgC ₂ H ₃ O ₂ ), gold sulfite (Au(SO ₃ ) ₂ ^2- ), chloroauric acid ( HAuCl ₄ ), chloroplatinic acid (H ₂ PtCl ₆ ), copper nitrate (Cu(NO ₃ ) ₂ ), copper sulfate (CuSO ₄ ), copper chloride (CuCl ₂ ), nickel sulfate (NiSO ₄ ) or a combination thereof. In a specific embodiment, the surface 112b of the modified nanocellulose core 110b has an OK group, and then the surface 112b of the modified nanocellulose core 110b may be treated with, for example, silver nitrate to have a surface thereof. The OK group is replaced with an OAg group, but the invention is not limited thereto.

<Step S16>

Referring to FIG. 2D, FIG. 3D and FIG. 4, step S16 is performed to perform a first reduction reaction to reduce the metal ion 120a of the metal seed crystal formation point to form a metal (atomic) seed crystal 120b. That is, the surface 112d of the nanocellulose core 110d has a plurality of metal seed crystals 120b. In some exemplary embodiments, the plurality of metal seed crystals 120b are, for example, silver atomic seeds.

In some embodiments, the reducing agent for reducing the metal ion 120a of the metal seed generation point is, for example, ascorbic acid, hydrazine, sodium borohydride, formaldehyde, glucose, sodium citrate, urea , diethanolamine, triethanolamine, methanol, ethanol, ethylene glycol, glycerol or a combination thereof. In some embodiments, the reaction temperature of the metal ion 120a at the point of reduction of the metal seed crystal formation point is, for example, between 0 degrees Celsius and 250 degrees Celsius, for example, in an ice bath, a heating environment, or a room temperature.

In a specific exemplary embodiment, the surface 112a of the nanocellulose core 110a is treated with potassium hydroxide, and its hydroxyl group (C6-OH) is substituted with an OK group (step S12). Next, the surface 112b of the modified nanocellulose core 110b is treated with a silver nitrate solution, and the OK group of the surface 112b is replaced with an OAg group (step S14). Thereafter, ascorbic acid is used as a reducing agent, and the OAg group is reduced to an Ag atom to serve as an Ag metal seed crystal (step S16).

<Step S18>

Referring to FIG. 2E, FIG. 3E and FIG. 4, step S18 is performed to perform a second reduction reaction to reduce the metal seed crystal 120b to form a metal outer shell 120 to coat the surface of the modified nanocellulose inner core, that is, this The surface 112e of the nanocellulose inner core 110d is coated with a metal outer casing 120. In detail, the second reduction reaction is performed by using the metal seed crystal 120b as a growth point, and the second metal growth is performed by the metal precursor and the reducing agent, the kinds of the metal precursor and the reducing agent, and the temperature of the reduction reaction are as above. The details are not described herein. In some embodiments, the second reduction reaction may additionally include a polymer such as polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polyacrylic acid (PAA), or a combination thereof. The thickness, material, and the like of the metal casing 120 are as described above, and will not be described herein.

The composite material of the present invention can be used, for example, as a material in conductive ink. It is worth mentioning that the composite material of the present invention can be formed into a desired size range by controlling the size (diameter, length, etc.) of the inner core of the nanocellulose. For example, the length of the composite material can be controlled between 50 nm and 5000 nm, so that the problem of nozzle clogging of the conductive ink during printing can be effectively solved. Further, in the composite material of the present invention, nano cellulose is used as the inner core, and since the nano cellulose has high crystallinity, the mechanical strength of the entire composite material can be improved. And the inner core of nano cellulose can be used as a supporting template to prevent metal melting from affecting electrical properties.

Further, in the manufacturing process of the composite material of the present invention, after forming the inner core of the nanocellulose, the metal shell is coated on the surface of the inner core of the nanocellulose, and then the nanocellulose core is not required to be removed. A step of. That is to say, if the composite material of the present invention is used as a material of the conductive ink, the conductive line can be directly printed to form a conductive line, and the nano cellulose core is not required to be removed later, so that the process can be simplified.

In summary, the composite material of the present invention comprises a nanocellulose inner core and a metal outer shell, wherein the metal outer shell covers the surface of the inner core of the nanocellulose. From the structural point of view, the size of the composite material of the present invention can be controlled within the range of nanometer size, so that the problem of clogging due to excessive size can be effectively reduced. Further, in the composite material of the present invention, since nano cellulose is used as the inner core, it has high crystallinity, so that the mechanical strength of the entire composite material can be improved. And the inner core of nano cellulose can be used as a supporting template to prevent metal melting from affecting electrical properties. From the viewpoint of the process, in the manufacturing process of the composite material of the present invention, the metal outer shell is defined by the inner core of the nano cellulose, and the subsequent step of removing the inner core of the nano cellulose is not required, so that the process is simplified.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

100‧‧‧Composite materials

S10, S12, S14, S16, S18‧‧ steps

110, 110a, 110b, 110c, 110d‧‧‧ nano cellulose core

112a, 112b, 112c, 112d, 112e‧‧‧ surface

120‧‧‧Metal casing

120a‧‧‧ Metal ions at the point of formation of metal seeds

120b‧‧‧metal seed crystal

1 is a schematic illustration of a composite material in accordance with some embodiments of the present invention. 2A-2E are schematic views showing a manufacturing process of a composite material according to some embodiments of the present invention. 3A to 3E are schematic diagrams showing the surface chemical structures of the composite materials of Figs. 2A to 2E, respectively. 4 is a schematic flow chart of a method of manufacturing a composite material according to some embodiments of the present invention.

Claims (18)

A composite material comprising: a nanocellulose inner core; and a metal outer shell covering a surface of the nanocellulose inner core, wherein the composite material has a length of between 50 nanometers and 5000 nanometers. The composite of claim 1, wherein the composite has a length to diameter ratio of between 1.5:1 and 500:1. The composite material of claim 1, wherein the composite material has a diameter of between 2 nm and 200 nm. The composite material according to claim 1, wherein the material of the nanocellulose core comprises cellulose nanofilament, cellulose nanocrystal, cellulose cellulose or a combination thereof. The composite material of claim 1, wherein the nanocellulose core is solid. The composite material according to claim 1, wherein the nanocellulose inner core has a diameter of between 2 nm and 200 nm. The composite material according to claim 1, wherein the material of the metal casing comprises gold, silver, palladium, platinum, rhodium, copper, tungsten, nickel, aluminum or a combination thereof. The composite material of claim 1, wherein the metal outer shell has a thickness of between 2 nm and 200 nm. A method of manufacturing a composite material comprising: providing a nanofiber inner core; Modifying the inner core of the nanocellulose; forming a metal ion to form a metal ion on the surface of the modified nanocellulose core; performing a first reduction reaction to reduce metal ions at the metal seed formation point Forming a metal seed; and performing a second reduction reaction, reducing the metal ions at the metal seed formation point at the metal seed to form a metal shell covering the modified nanocellulose core surface. The method for producing a composite material according to claim 9, wherein the step of modifying the inner core of the nanocellulose is by a metal substitution reaction with a hydroxyl group on the carbon of the inner core of the nanocellulose to form A hydroxyl group substituted with a metal. The method for producing a composite material according to claim 10, wherein the metal ion forming point metal ion is formed on the metal-substituted hydroxyl group. The method for producing a composite material according to claim 9, wherein the step of modifying the inner core of the nanocellulose comprises subjecting the nanocellulose core to a substitution reaction with potassium hydroxide. The method for producing a composite material according to claim 9, wherein the reducing agent for performing the first reduction reaction and the second reduction reaction comprises ascorbic acid, hydrazine, sodium borohydride, formaldehyde, glucose, citric acid. Sodium, urea, diethanolamine, triethanolamine, methanol, ethanol, ethylene glycol, glycerol or a combination thereof. The method for producing a composite material according to claim 9, wherein the metal ions forming the metal seed crystal formation point and the metal precursor for performing the second reduction reaction include silver nitrate, silver nitrite, silver sulfate, Silver chloride, silver perchlorate, silver cyanate, silver carbonate, silver acetate, gold sulfite, chloroauric acid, chloroplatinic acid, copper nitrate, copper sulfate, copper chloride, nickel sulfate or a combination thereof. The method of producing a composite material according to claim 9, wherein the performing the second reduction reaction further comprises adding a polymer. The method of producing a composite material according to claim 15, wherein the polymer comprises polyvinylpyrrolidone, polyvinyl alcohol, polyacrylic acid or a combination thereof. The method for producing a composite material according to claim 9, wherein the reaction temperature of the first reduction reaction and the second reduction reaction is between 0 ° C and 250 ° C. The method of manufacturing a composite material according to claim 9, wherein the material of the metal casing comprises gold, silver, palladium, platinum, rhodium, copper, tungsten, nickel, aluminum or a combination thereof.