The Investigation Of Smart Textile With High Flexibility Realized By Cross-linking Of Polyacrylate Based Thermo-responsive Copolymers To Cotton Fabrics

Smart textiles arises and brings revolution of the life in recent years.The development and application of textiles embody the innovative and high technology applied to textile and have a great research value,which is a multi-disciplinary integration including textile,biology,chemistry,physical and electronic information.The function of smart textiles is realized by smart materials,due to the fast and abrupt thermal response without any chemical regents,the related structures of thermoresponsive polymer have been widely investigated.With the thermal stimulus,thermoresponsive polymers undergo the alternation of the volume swelling/deswelling,surface hydrophilicity/hydrophobicity,these unique properties will contribute to the application in smart material.Unique functions and high value will be added to traditional textiles by introduction of themo-responsive polymers through physical or chemical methods.Thus,thermo-responsive polymers will have promising application in smart textile.The thermo-responsive polyacrylate with flexible side chain were synthesized,the influence of the molecular state and structure on the phase transition behavior were investigated and identified.Further with the substrate of regenerated cellulose,the combination of cross-linked thermo-responsive on the cotton fabric was simulated.The influence of the substrate on the surface topography and phase transition behavior were studied,which lays the foundation of the fabrication of flexible and smart textile.With a cross-linking reaction,the thermo-responsive polymer was introduced to the cotton fabric,the flexible and smart textile possessing the properties of smart cleaning,confort regulation and inhibition of bacterial adhesion were obtained.The thermo-responsive random copolymer poly(2-(2-methox yethox y)ethylmethacrylate)-co-oligo(ethyleneglycol)methacrylate)and poly(2-(2-methoxyethoxy)ethylmethacrylate)-co-(ethyleneglycol)methacrylate)with a monomer molar V ratio of 17:3,abbreviated as P(MEO2MA-co-OEGMA300)and P(MEO2MA-co-EGMA360)respectively,were synthesized by atom transfer radical polymerization,and the influence of the molecular state and structure on the phase transition behavior were investigated.In aqueous solution,the phase transition temperature(TT)of P(MEO2MA-co-OEGMA300)and P(MEO2MA-co-EGMA360)with a concentration of 10 mg/m L are 35 and 36 oC,and P(MEO2MA-co-EGMA360)exhibits a broader phase transition region.As for the polymer films,the P(MEO2MA-co-EGMA360)has a enhanced swelling capacity due to the extra hydroxyl groups.However,the hydroxyl groups will form intermolecular hydrogen bonding with surrounding water even the temperature exceeds TT,which induces the less pronounced thermo-responsive property of P(MEO2MA-co-EGMA360)film.As a result,the P(MEO2MA-co-EGMA360)film has a wider phase transition region than P(MEO2MA-co-OEGMA300),this phenomenon agrees with the polymer in aqueous solution.Moreover,because the phase transition behavior of polymer film on Si substrate can only occur on the vertical direction,that is the change of film thickness,the phase transition is milder than that of P(MEO2MA-co-OEGMA300).For further undestanding the influence of sunbstrate on the surface topography and phase transition behavior of cross-linked thermo-responsive polyacrylate,trimethyl cellulose with surface enrichment of alkyl groups was synthesized and formed a polymer film layer on Si substrate by spin-coating,then the alkyl groups were replaced with hydroxyl to obtain a regenerated cellulose layer on Si substrate.Afterwards,the thermo-responsive P(MEO2MA-co-EGMA360)was incorporated into the regenerated cellulose film by cross-linking.A homogenous TMSC film was obtained by spincoating of TMSC with a DS of 2.21 which was dissolved in chloroform.After substitution reaction,the regenerated cellulose film with a thickness of 25 nm was generated on the surface of TMSC.Above transition temperature,due to the crosslinking network structure,the mobility of polymer chain was limited in the phase transition.The neighbouring chains of cross-linked polymer film on RC film only moved closer together,resulting in appearing gaps and pores at the lowest level of substance where previously covered by the polymer.Due to the thermo-responsive VI property,the film thickness of the cross-linked polymer had an abrupt drop during 35-40 oC and the surface switched from hydrophilicity to hydrophobicity,which laid the foundation of the fabrication of flexible and smart textile.The smart cleaning and comfort control of cotton fabric by cross-linking P(MEO2MA-co-EGMA360)were investigated.After treatment of cotton fabric with the finishing solution containing 8 wt% polymer and curing at 130 oC for 2 minutes,the cotton fabric cross-linked with P(MEO2MA-co-EGMA360)was obtained.The abrupt change of equilibrium swelling ratio,contact angle and wetting time during 35-40 oC indicate that the cotton fabric cross-linked with P(MEO2MA-co-EGMA360)possesses thermo-responsive property.Due to the hydrophilicity of thermo-responsive polymer below transition temperature,the cleaning ability of the cotton fabric with cross-linked P(MEO2MA-co-EGMA360)can be prominently enhanced.Besides,the porous structure of the polymer layer will form above TT,enhancing the air and moisture permeability as well as the body comfort.Moreover,the whiteness,softness and mechanical properties of the cotton fabric with cross-linked P(MEO2MA-co-EGMA360)were studied and that did not change after cross-linking.Considering the biological compatibility of PNIPAM and the prominent decrease of Tg for PNIPAM by copolymerization with PEGMA360,cotton fabric crossed-linked with poly(n-isopropyl acrylamide-co-ethylene glycol methacrylate),abbreviated as P(NIPAM-co-EGMA360),was prepared and characterized.With the increasing molar ratio of EGMA360,the thermo-reaponsive copolymer P(NIPAM-co-EGMA360)had a lower glass transition temperature(Tg),weaker thermal stability and higher transition temperature(TT).Specially,the thermo-responsive copolymer P(18NIPAM-co-2EGMA360)present a Tg of 0 oC and a TT of 40 oC in aqueous solution with a concentration of 1 mg/m L.Therefore,the introduction of P(18NIPAM-co-2EGMA360)into the cotton fabric will have little influence on the softness of the fabrics.The phase transition region of cotton fabric cross-linked with P(18NIPAM-co-2EGMA360)ranges from 36 to 39 oC.Due to the cross-linked P(NIPAM-co-EGMA360)layer on the cotton fabrics,the porosity of the polymer layer can be adjusted by varying the external temperature below or above TT,showing that the regulation of the air and moisture permeability as well as the body comfort are feasible to the cotton fabrics cross-linked with P(NIPAM-co-EGMA360).In addition,the cross-linked P(NIPAM-co-EGMA360)layer is capable of absorbing moisture in the ambient atmosphere and form a hydrated layer on top,which can inhibit bacterial adhesion to the textiles.The cotton fabric crosslinked with P(18NIPAM-co-2EGMA360)had excellent washing fastness and permanent thermo-reponsive property,which can meet the requirements of the daily life.