WO2013032859A1 - Articles en nanofibres à réaction rapide avec mouillabilité et propriétés volumiques réglables - Google Patents

Articles en nanofibres à réaction rapide avec mouillabilité et propriétés volumiques réglables Download PDF

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Publication number
WO2013032859A1
WO2013032859A1 PCT/US2012/052070 US2012052070W WO2013032859A1 WO 2013032859 A1 WO2013032859 A1 WO 2013032859A1 US 2012052070 W US2012052070 W US 2012052070W WO 2013032859 A1 WO2013032859 A1 WO 2013032859A1
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fibers
polymer
fiber
mat
pnipa
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PCT/US2012/052070
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English (en)
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Wolfgang M. Sigmund
Palanikkumaran MUTHIAH
Tim Boyle
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University Of Florida Research Foundation, Inc.
Sandia National Laboratories, New Mexico
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Priority to US14/240,963 priority Critical patent/US20140213136A1/en
Publication of WO2013032859A1 publication Critical patent/WO2013032859A1/fr

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    • D—TEXTILES; PAPER
    • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
    • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
    • D04H1/70—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres
    • D04H1/72—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres the fibres being randomly arranged
    • D04H1/728—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres characterised by the method of forming fleeces or layers, e.g. reorientation of fibres the fibres being randomly arranged by electro-spinning
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
    • D01D5/00—Formation of filaments, threads, or the like
    • D01D5/0007—Electro-spinning
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
    • D01F6/28—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • D01F6/36—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds comprising unsaturated carboxylic acids or unsaturated organic esters as the major constituent
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
    • D01F6/44—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds as major constituent with other polymers or low-molecular-weight compounds
    • D01F6/56—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from mixtures of polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds as major constituent with other polymers or low-molecular-weight compounds of polymers of cyclic compounds with one carbon-to-carbon double bond in the side chain
    • D—TEXTILES; PAPER
    • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
    • D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
    • D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
    • D04H1/54—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by welding together the fibres, e.g. by partially melting or dissolving
    • D04H1/542—Adhesive fibres
    • D04H1/544—Olefin series
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
    • Y10T442/60—Nonwoven fabric [i.e., nonwoven strand or fiber material]
    • Y10T442/608—Including strand or fiber material which is of specific structural definition
    • Y10T442/614—Strand or fiber material specified as having microdimensions [i.e., microfiber]
    • Y10T442/615—Strand or fiber material is blended with another chemically different microfiber in the same layer
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
    • Y10T442/60—Nonwoven fabric [i.e., nonwoven strand or fiber material]
    • Y10T442/608—Including strand or fiber material which is of specific structural definition
    • Y10T442/614—Strand or fiber material specified as having microdimensions [i.e., microfiber]
    • Y10T442/626—Microfiber is synthetic polymer

Definitions

  • Switchable materials are engineered to respond to an external stimulus, such as light irradiation, pH changes, solvent exposure, electrical potential, magnetic field, mechanical force, or temperature.
  • Thermally responsive materials are of particular interest due to the narrow temperature response and the predictable properties the materials can display upon undergoing the transition. The switchable responses result from structural changes to the material as the properties change.
  • PNIPA Poly(N-isopropylacrylamide)
  • LCST critical solution temperature
  • the polymer's repeating units display a reversible hydrogen bonding preference for water molecules or other repeating units of the polymer due to enthalpic and entropic contribution to the free energy of PNIPA chains.
  • entropic contributions dominate the enthalpic contributions of bonding with water, and hydrogen bonding occurs between repeating units of the polymer chains rather than with water molecules, which causes the PNIPA chains to exist in collapsed "globular conformations" and to precipitate from solution.
  • PNIPA reversible extreme wettability
  • Embodiments of the invention are directed to a fibrous properties-switching article whose properties rapidly and reversibly switch over a range of temperatures.
  • the article comprises a mat consisting of fibers of at least one polymer, copolymer, polymer blend, and/or polymer network with narrow fiber size distribution, having a diameter of about 2 ⁇ or less, where the material undergoes a structural change over the range of temperatures, which causes the surface and/or bulk property of the mat to change over the range of temperatures.
  • the structural change is a conformational change in N-isopropyl acrylamide units of poly((N-isopropylacrylamide), where the hydrogen bonding of the amide switches from bonding with water at low temperatures to intramolecular bonding between repeating units of the polymer at higher temperatures.
  • Fiber mats of a polymer blend of polystyrene and poly((N- isopropylacrylamide) (bl-PS/PNIPA) and of crosslinked poly(N-isopropylacrylamide-co- methacylicacid) (xl-PNIPAMAA) display dramatic changes in their hydrophilicity over a relatively narrow temperature range. The switching speed that can be achieved depends on the diameter of the fibers in the mat, with very high switching speeds possible for very small diameter fibers.
  • Embodiments of the invention are directed to the preparation of mats of very small fibers by electrospinning.
  • a mat is formed that displays exclusively fibers by SEM.
  • the bl-PS/PNIPA fiber mat is spun from dimethylformamide (DMF), which, suprisingly, gives exclusively fibers with no particles being observed, as is the case when a THF solvent is employed.
  • a PNIPAMAA fiber mat is spun from DMF and subsequently heated to crosslink the fibers.
  • Figure 1 shows digital photographic images of dye solutions placed on a) a blended polystyrene/poly((N-isopropylacrylamide) (bl-PS/PNIPA) fiber mat according to an embodiment of the invention and b) a crosslinked poly(N-isopropylacrylamide-co- methacylicacid) (xl-PNIPAMAA) fiber mat according to an embodiment of the invention showing reversible, extreme wettability (REW) properties.
  • bl-PS/PNIPA blended polystyrene/poly((N-isopropylacrylamide)
  • xl-PNIPAMAA crosslinked poly(N-isopropylacrylamide-co- methacylicacid)
  • Figure 2 shows scanning electron microscopy (SEM) images of a) a bl-PS/PNIPA fiber mat according to an embodiment of the invention and b) xl-PNIPAMAA fiber mat according to an embodiment of the ivention, and c) a transmission electron microscopy (TEM) image of the bl-PS/PNIPA fiber mat where the PS and PNIPA blending at the nanoscale dimensions are apparent.
  • SEM scanning electron microscopy
  • TEM transmission electron microscopy
  • Figure 3 shows a plot of the contact angle (CA) over a range of temperatures for bl- PS/PNIPA and xl-PNIPAMAA fiber mats according to embodiments of the invention.
  • Figure 4 shows a plot of CA against temperature during cycling of the temperature for bl-PS/PNIPA and xl-PNIPAMAA fiber mats according to embodiments of the invention, where the bl-PS/PNIPA fiber mats were cycled between 15 °C and 65 °C and the xl- PNIPAMAA fiber mats were cycled between 20 °C and 95 °C.
  • Figure 5 shows SEM images of bl-PS/PNIPA fiber mat according to an embodiment of the invention, with fibers of diameter: a) 380; b) 990; c) 1500; and d) 16000 nm.
  • Figure 6 shows photographs of water droplets on a 380 nm diameter fiber bl- PS/PNIPA fiber mat, according to an embodiment of the invention at 65 °C and 25 °C, where the mat is superhydrophobic and superhydrophilic, respectively.
  • Figure 7 shows selected photographic images taken at the indicated time in seconds after placing a fiber mat, according to an embodiment of the invention, supporting a water droplet on top a metal bar maintained at -30 ⁇ 3, where a) a 380 nm fiber bl-PS/PNIPA mat transformed from superhydrophobic to superhydrophilic within 5 seconds, and where b) a 16000 nm fiber bl-PS/PNIPA mat resulted in freezing of the water droplet before wetting of the surface to an appreciable degree.
  • Figure 8 shows DSC plots of PNIPAMAA dissolved in water and hydrated xl- PNIPAMAA fibers.
  • Figure 9 shows SEM images of the sections of fiber mats in the presence of water after the heating and cooling cycles that are illustrated in Figure 4 were carried out, for mats of a) bl-PS/PNIPA and b) xl-PNIPAMAA according to embodiments of the invention.
  • Embodiments of the invention are directed to preparing and using articles having surface and/or bulk properties that change upon a change of temperature.
  • a fiberous surface that displays reversible extreme wettability (REW) is formed by electrospinning, as shown in Figure 1 for exemplary embodiments.
  • the electrospinning readily produces a mat of fibers, where the rate of response and the switching rate of the resulting fiber mat is controlled by the diameter of the fiber.
  • the fibers have diameters that range from about 100 nm to about 2 ⁇ in diameter depending on predetermined conditions employed.
  • This process involves the imposition of a high electrical field, for example, l-5kV/cm, to a polymer droplet as it exits an orifice, for example, the end of a needle.
  • the applied high electrical force overcomes the surface energy of the droplet and forms a Taylor cone where a stream of liquid erupts from the droplet.
  • the mode of current flow changes from ohmic to convective as the charge migrates to the surface of the fiber.
  • the stream is elongated by a whipping process caused by electrostatic repulsion initiated at small bends in the fiber, until the fibers are deposited on a grounded collector.
  • the elongation and thinning of the fiber, resulting from bending instability leads to formation of uniform fibers, often displaying nanometer-scale diameters, and results in a mat of fibers on the collector that possess a high surface area to mass ratio.
  • properties switching articles are prepared from polystyrene/poly(N-isopropylacrylamide) blends (bl-PS/PNIPA), and poly(N-isopropyl acrylamide-co-methacylicacid) (PNIPAMAA) are used to produce REW articles by electrospinning.
  • the fiber mats of blended PS/PNIPA (bl-PS/PNIPA) and crosslinked PNIPAMAA (xl-PNIPAMAA) display REW properties while maintaining integrity at temperature ranges that are broad.
  • a fiber mat was produced from bl-PS/PNIPA that exhibited exclusively fibers, as shown in Figure 2a.
  • the fiber mat was produced by electrospinning the blend from a dimethylformamide (DMF) solution of the bl-PS/PNIPA, indicating that the nature of the solvent is critical to the electrospinning of fibers.
  • DMF dimethylformamide
  • Analysis by TEM of the bl-PS/PNIPA fiber mat displays a blended structure where two distinct polymer phases with nanometer dimentions are apparent, as can be seen in Figure 2c.
  • the surface morphologies of the bl-PS/PNIPA and xl-PNIPAMAA fiber mats indicate that the fiber mats are exclusively fibers that have a uniform size distribution and a mean fiber diameter of 1950 nm for the mat from bl- PS/PNIPA and 870 nm for the mat from xl-PNIPAMAA.
  • D C00p for PNIPA varies between 10 *12 and 10 "10 m 2 s "1 depending upon the crosslinking density, polymer concentration, and temperature, with an inverse correlation between D coop and temperature, and with an order of difference in diffusion coefficients, 5> ⁇ 10 "12 and 2x l0 "n m 2 s "1 , for de- swollen gel at temperatures greater than 32 °C and water swollen gel at temperatures less than 32 °C, respectively.
  • the actual response time of a hydrogel largely depends upon gel thickness, or the fiber diameter for the fiber mats, according to an embodiment of the invention.
  • the response time can be controlled.
  • the rate at which the fiber can switch depends on heat transfer and/or water (or other chemical) diffusion through the fiber, which are processes whose rates vary with the cross-sectional area of the fiber.
  • the rate of switching can be dramatically decreased as the fiber's diameter decreases, allowing switching times that can occur in milliseconds or less when fiber diameters drop below a micrometer ( ⁇ ).
  • surface properties, such as wettability, and bulk properties, such as elastic modulus can vary dramatically, such materials can be useful in applications where an article comprising a polymeric material must respond to the environment it experiences, for example, a tire.
  • the property change results from a structural change of the material comprising the fiber; for example, the fiber can be constructed of a polymer that has functionality that undergoes a conformational change, a change in association, or a change in solvation.
  • the fibers can be those of a homopolymer, a copolymer, a polymer blend, or a polymer network.
  • the polymer changes structure from a polymer hydrogen bonded to water at low temperatures to a self hydrogen bonding polymer at higher temperatures, such that water is released when the polymer adapts a conformation for intramolecular hydrogen bonding.
  • Table 1 Calculated switching response times for fibers of different diameters.
  • CA Contact angle
  • the switching occurs between 30 °C and 45 °C for the fiber mat of bl- PS/PNIPA.
  • the bl-PS/PNIPA sample displays a CA that is 90 % of the steady state CA value for higher temperatures.
  • This REW of bl-PS/PNIPA and xl-PNIPAMAA fiber mats are shown in Figure 4 for the data of Table 3, below, for wetted fiber mats, where the temperature is cycled 5 times between temperatures displaying hydrophilic or superhydrophilic behavior and hydrophobic or superhydrophobic behavior.
  • Table 2 CA values of bl-PS/PNIPA and xl-PNIPAMAA fiber mats at various temperatures.
  • CA measurements carried out on electrospun PS/PNIPA fiber mats, shown in Figure 5, with different diameter fibers, according to an embodiment of the invention, are reported in Table 4, below.
  • the interaction between a liquid droplet and a porous structure conforms to the Cassie-Baxter (CB) model, where the relationship between CA and the porosity of a material is:
  • the electrospun fiber mats are a nonwoven fiber network with three dimensionally interconnected pores and grooves between the fibers.
  • the CA values at 65 °C given in Table 4 agree with values calculated using the CB model where a reduction in the fiber's diameter reduces the fraction of fiber area in contact with the water droplet such that a fiber mat constructed of sufficiently fine diameter fibers displays superhydrophobicity, with water CA values 150°, as given in Table 4.
  • Electrospun PS/PNIPA fiber mats, according to an embodiment of the invention show superhydrophobic to superhydrophilic switching. Table 4. Response time on PS/PNIPA blended fiber mats with different diameter fibers
  • Figure 7 graphically displays this transformation for a mat of a) 380 nm diameter fibers and of b) 16 ⁇ diameter fibers.
  • Table 4 gives the fiber diameter, fiber mat thickness, CA value measured at 65 °C, and the cold source used to study response time. All fiber mats are superhydrophilic with a 0° CA value at 25 °C.
  • the REW properties of the xl-PNIPAMAA fiber mats is indicated by a transition temperature that can be observed in a DSC measurement and occurs at the temperature where the fiber mat's surface changes from hydrophilic to hydrophobic during heating and from hydrophobic to hydrophilic properties during cooling.
  • the xl-PNIPAMAA fiber mat exhibits an upward shift in transition temperature, observed as a strong broad peak at 82.7 °C in a DSC plot, which differs from that of -32 °C for the transition displayed by PNIPAMAA in water, indicating that transition temperature for the material increases upon crosslinking, as indicated in Figure 8.
  • the presence of PVA in xl-PNIPAMAA causes the fiber mat to be more hydrophilic than in the absence of PVA, shifting the transition point to a higher temperature.
  • the CA measurements of the xl- PNIPAMAA fiber mat reveal a response between hydrophilic and nearly hydrophobic, where hydrophobicity is indicated by CA value that is >90°.
  • the CA values vary from 20.5° ⁇ 6.5 to 87.0° ⁇ 3.0 for the xl-PNIPAMAA fiber mat as the temperature varies from 20 °C to 95 °C, as indicated in Table 2, above, and plotted in Figure 3.
  • Figure 4 shows that the temperature cycling of the xl-PNIPAMAA results in a switching between hydrophilic and nearly hydrophobic behavior of the mat's surface.
  • the fiber mats are those where the solubility of the fiber mat in water is inhibited.
  • the solubility is inhibited by blending a polymer that is water soluble below the LCST with a polymer that is insoluble in water at all temperatures.
  • a water soluble polymer is crosslinked to a water swellable, yet insoluble material. Leaching experiments were carried out where vacuum dried fiber mats were water washed with stirring at 10 °C for 24 hours and agian vacuum dried. Result of the experiments, as inidicated in Table 5, below, suggest that other factors than just the dissolving of water soluble portions of the mats affected the results.
  • the 83.3 % weight loss of the bl-PS/PNIPA indicated a retention of only 16.7 % of the mass, even though approximately 70 % of the mat's mass was blended polystyrene, which is water insoluble.
  • the xl-PNIPAMAA fiber mat lost 53.3 % of its mass upon washing, although it was, in principle, a crosslinked mass that should swell but not dissolve in water.
  • the crosslinking reactions that occur in PNIPAMAA can include: anhydride formation between carboxylic acid groups of PNIPAMAA; esterification between carboxylic acid groups of PNIPAMAA and alcohol groups of poly(vinyl alcohol) (PVA); and/or imidization between carboxylic acid groups and amide groups of PNIPAMAA. It is reasonable that all three of the reactions with the carboxylic acid groups contribute to crosslinking the electrospun PNIPAMAA fibers during heat treatment at 160 °C in a vacuum oven.
  • Polystyrene (PS) (M n 170,000 g/mol and M w 350,000 g/mol), polyfN- isopropylacrylamide-co-methacrylic acid) (PNIPAMAA) (M n 60,000 g/mol, 90 mol % PNIPA and 10 mol % MAA), disodium hydrogen phosphate (DSHP), and dimethylformamide (DMF) were used as received from Sigma-Aldrich.
  • PolyfN- isopropylacrylamide) (PNIPA) (M v -40,000 g/mo) was used as received from Polyscience Incorporation.
  • Polyvinyl alcohol) (PVA) (75 % hydrolyzed and MW 2,000) was used as received from Acros Organics. Glacial acetic acid (99.9 % HOAc) was used as received from Fisher.
  • a 15 % wt blend solution of PS and PNIPA (PNIPA/PS 30/70 wt/wt) was prepared by dissolving the polymers in DMF.
  • the blend solution was placed in a 3 mL syringe, fitted with an 18-gauge stainless steel needle (inner diameter of 0.965 mm).
  • the syringe was fixed horizontally on a syringe pump (Model: BSP-99M, Braintee Scientific Inc.), and an electrode connected to a high voltage power supply (Model: ES30N-5W, Gamma High Voltage Research) was attached to the tip of the metallic needle.
  • a grounded stationary square collector (10 cm x 10 cm) covered by a piece of clean aluminum foil was used for fiber collection.
  • Electrospinning to produce bl-PS/PNIPA with 870 nm fibers, was carried out using the blend solution under the following operating conditions: a flow rate (FR) of 0.90 mL/h; an electric field (EF) of 0.8 kV/cm; and a distance between the needle and the collecting plate (Dcp) of 1 1 cm. Electrospinning was performed for about 30 mins.
  • PS/PNIPA blended fiber mats with diameter of the fiber 380, 990, 1.5K and 16K nm were fabricated by varying the blend solution concentration, flow rate, distance between the needle tip and collector surface (Dcp) or gap distance, electric field, and needle gauge in electrospinning given in Table 6, below. Attempts to produce higher diameter fibers yielded fibers that were fused together.
  • Water stock solutions of 15 % wt NIPAMAA/HOAc, 15 % wt PVA/DI water, and 10 % wt DSHP/DI were prepared.
  • a formulation was generated by mixing 0.68 g of the PNIPAMAA/HOAc solution with 15 % wt PVA/DI water to yield 5 % wt PVA relative to PNIPAMAA and 30 % wt DSHP relative to PVA.
  • Electrospinning was carried out using the formulation under the following operating conditions: FR of 0.43 mL/h; EF of 1 kV/cm; and Dc of 20 cm. Electrospun fibers were collected on a 1 mm thick glass slide (size 7.6 cm x 2.5 cm) for 3 mins.
  • the bottom of the glass slide was fixed to aluminum foil using a double- sided copper tape.
  • the collected electrospun fiber mats were kept in a vacuum oven at room temperature (RT) overnight, followed by a heat treatment at 160 °C for 30 minutes in a vacuum oven. Subsequently, samples were washed in cold water (10 °C) followed by hot water (100 °C) and this washing cycle was repeated two additional times.
  • Contact angle (CA) measurements were carried out on the fiber mats collected on a glass slide.
  • the surface morphology of bl-PS/PNIPA and xl-PNIPAMAA fiber mats were examined using a field emission gun SEM (Model: 6335F, Jeol), where a small portion of electrospun fiber mat was cut and fixed to a SEM stub using a double-sided adhesive carbon tape. Sample was sputter coated with a thin film of gold-palladium to aid in SEM analysis, and analyzed in SEM with an accelerating voltage of 10 kV. Additionally, the blended structure of bl-PS/PNIPA fiber mat was examined using TEM (Philips CM30), where a thin web of electrospun sample was collected on a copper grid and directly examined in TEM at an accelerating voltage of 300 kV.
  • CA measurements were carried out on electrospun samples using a Goniometer (Model: VCA Optima, AST Products, Inc.) instrument equipped with an automated dispensing system and a 30 gauge flat-tipped stainless steel needle.
  • the probe fluid, water, having resistivity >18 ⁇ -cm was collected using a nanopure Milli-Q purification system (Millipore Inc.). Sessile drop images were captured, by placing 2 ⁇ or 4 ⁇ water droplets onto the fiber mat at 5 different places.
  • the CA data were then obtained by Drop-Snake analysis, a plug-in for Image J software.
  • Mean fiber diameters of electrospun fiber mats were analyzed using Image J, a general purpose image processing software. Ten SEM images were obtained at different sites on each fiber mat. All fibers present in an image were measured for determining mean fiber diameter, where at least 150 individual fibers were measured for the analysis of each fiber mat.
  • Hydrated xl-PNIPAMAA fiber mats weighing -20 mg were used for DSC analysis.
  • Temperature scans were performed between 5 °C and 100 °C to analyze sample transition temperatures.
  • a 7.5 % wt PNIPAMAA in DI water was analyzed by DSC to determine its transition temperature.
  • heating was performed using a thin- flexible Kapton® heater (Model: KH-203/10, Omega Engineering, Inc.) and cooling was performed by a cryostage (Product Number: 39467506, SubzeroTM Freezing Microtome Stage, Leica) attached to a cooler maintained at 24 ⁇ 1 °C using a water bath-circulator.
  • Fiber mats either collected on aluminum foil or a glass slide, were attached to a silicon wafer by a double-sided carbon adhesive tape. The silicon wafer was fixed to a flexible heater and a cryostage using scotch tape and the entire setup was placed on Goniometer stage.
  • thermocouple (Model: SA1-K-SRTC, Omega Engineering, Inc.) connected with a temperature meter (Model: BS5001k2, Omega Electronics, Inc.) was adhered to the fiber mat to read its surface temperature.
  • the flexible Kapton® heater was powered by a DC power supply (Model: 6218 A, Agilent HP), the temperature on the fiber mat was adjusted by controlling the voltage current.
  • the DC power supply was switched on during heating cycles and the cryostage was switched on during cooling cycles. The temperature was measured with ⁇ 1 °C accuracy.
  • the 24 °C cryostage was replaced with a metal bar at a temperature of -30 ⁇ 3 °C, that was maintained using liquid N 2 as the coolant.
  • Droplets placed over 16K nm diameter fiber mats froze after 25-30 seconds, whereas response time measurements using a stage at 24 ⁇ 1 °C, was found to be 47.4 ⁇ 1.9 s.
  • the fraction of the wet solid contact area of electrospun fiber mats was obtained using Image J software.
  • the image was first converted 32-bit type: image > type > 32-bit.
  • the threshold level was determined by adjusting and measuring to obtain the fraction of the wet solid contact area: image > adjust > threshold. Determination of Response Time on PS/PNIPA Blended Fiber Mats
  • PS/PNIPA Blended fiber mats response time was investigated by capturing and analyzing the video for the transition from a maximum to minimum CA. The camera captures 60 frames per second. Fiber mat collected on aluminum (Al)-foil was glued to silicon (Si)- wafer using double-sided adhesive carbon tape to ensure a flat fiber mat surface that facilitated the response time studies. A thermocouple (Model: SA1-K-SRTC, Omega Engineering, Inc.) was glued on top of the fiber mat and was connected to a temperature meter (Model: BS5001k2, Omega Electronics, Inc.) to monitor the fiber mat's surface temperature.
  • a fiber mat was heated to 65 ⁇ 1 °C by resistive heating, using a thin and flexible Kapton® heater (Model: KH-203/10, Omega Engineering, Inc.) with help of a DC power supply (Model: 6218A, Agilent HP), where upon reaching 65 °C, a 4 xL volume dye solution (50 ppm concentration Procion red dye prepared in water) was placed above the fiber mat using a pipette.
  • the fiber mat was transferred to the top of a metal bar maintained at - 30 ⁇ 3 °C using liquid N 2 .
  • the start time was when the Si-wafer with the fiber mat assembly fully contacted the metal bar and the end time was noted when the dye solution reached a minimum CA value.
  • the response time was determined as an average of 5 values from 5 different spots.
  • the measurements were conducted in an enviroment with relative humidity and temperature of 45 % and 25 °C, respectively.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Nonwoven Fabrics (AREA)
  • Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)

Abstract

L'invention concerne un article fibreux à propriétés modifiables, comportant une natte constituée de fibres présentant un diamètre de fibres inférieur ou égal à 2 microns. Les fibres comportent un polymère, un copolymère, un mélange de polymères ou un réseau de polymères, caractérisé en ce que les fibres présentent un diamètre inférieur ou égal à 2 μm. La propriété surfacique et / ou volumique de la natte varie sur une plage de températures, le polymère, le copolymère, le mélange de polymères ou le réseau de polymères subissant un changement structural sur la plage de températures. La natte de fibres est formée par électro-filage. Dans un mode de réalisation décrit à titre d'exemple, un mélange de polystyrène et de poly((N-isopropyl acrylamide) (bl-PS/PNIPA) dans du diméthylformamide (DMF) subit un électro-filage pour former un constitué de fibres d'un diamètre inférieur à 2 μm qui présente une transition d'une surface super-hydrophile à une surface quasi super-hydrophobe sur une plage de températures allant de 30°C à 45°C. Une natte de fibres formée par électro-filage d'une solution de DMF comportant du poly(N-isopropyl acrylamide-co-acide méthacrylique) (PNIPAMAA), comporte des fibres qui présentent un diamètre inférieur à 2 μm et qui sont réticulées après filage. La natte en fibres de PNIPAMAA réticulées (xl-PNIPAMAA) présente une transition d'une surface hydrophile à une surface quasi hydrophobe sur une plage de températures allant de 30°C à 45°C.
PCT/US2012/052070 2011-08-26 2012-08-23 Articles en nanofibres à réaction rapide avec mouillabilité et propriétés volumiques réglables WO2013032859A1 (fr)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014109379A1 (fr) * 2013-01-11 2014-07-17 独立行政法人物質・材料研究機構 Nanofibre ayant des propriétés autochauffantes et des propriétés de libération de substance biologiquement active, son procédé de production et tissu non tissé ayant des propriétés autochauffantes et des capacités de libération de substance biologiquement active
US9863243B1 (en) 2015-04-28 2018-01-09 National Technology & Engineering Solutions Of Sandia, Llc Ruggedized downhole tool for real-time measurements and uses thereof
CN107587268A (zh) * 2017-08-24 2018-01-16 东华大学 一种环保溶剂型静电纺防水透湿膜的制备方法
CN109252289A (zh) * 2018-08-24 2019-01-22 合肥工业大学 一种响应性聚(n-异丙基丙烯酰胺)/金棒/木纤维复合材料的制备方法

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109134746B (zh) * 2017-04-18 2020-09-08 苏州大学 一种智能型织物及其应用
CN112853739B (zh) * 2021-03-02 2022-11-04 浙江理工大学 一种温度响应型Janus纳米纤维敷料的制备方法
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TWI821653B (zh) * 2021-04-15 2023-11-11 財團法人紡織產業綜合研究所 感溫調濕纖維及其製備方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090130773A1 (en) * 2005-10-13 2009-05-21 Teck Choon Ayi Method of Enhancing a Fluorescent Signal
US20100216240A1 (en) * 2007-09-07 2010-08-26 Csir Non-invasive automated cell proliferation apparatus

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090130773A1 (en) * 2005-10-13 2009-05-21 Teck Choon Ayi Method of Enhancing a Fluorescent Signal
US20100216240A1 (en) * 2007-09-07 2010-08-26 Csir Non-invasive automated cell proliferation apparatus

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
SONG, F. ET AL.: "Fabrication of novel thermo-responsive electrospun nanofibr ous mats and their application in bioseparation.", EUROPEAN POLYMER JOURNAL., vol. 47, no. 10, 12 August 2011 (2011-08-12), pages 1885 - 1892 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014109379A1 (fr) * 2013-01-11 2014-07-17 独立行政法人物質・材料研究機構 Nanofibre ayant des propriétés autochauffantes et des propriétés de libération de substance biologiquement active, son procédé de production et tissu non tissé ayant des propriétés autochauffantes et des capacités de libération de substance biologiquement active
JP5867839B2 (ja) * 2013-01-11 2016-02-24 国立研究開発法人物質・材料研究機構 自己発熱性及び生理活性物質放出性を有するナノファイバー、その製造方法並びに自己発熱性及び生理活性物質放出機能性不織布
US9863243B1 (en) 2015-04-28 2018-01-09 National Technology & Engineering Solutions Of Sandia, Llc Ruggedized downhole tool for real-time measurements and uses thereof
CN107587268A (zh) * 2017-08-24 2018-01-16 东华大学 一种环保溶剂型静电纺防水透湿膜的制备方法
CN107587268B (zh) * 2017-08-24 2020-08-11 东华大学 一种环保溶剂型静电纺防水透湿膜的制备方法
CN109252289A (zh) * 2018-08-24 2019-01-22 合肥工业大学 一种响应性聚(n-异丙基丙烯酰胺)/金棒/木纤维复合材料的制备方法

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