高导电镀银织物的制备及其在电致变色中的应用

Preparation of highly conductive silver-plated fabrics for electrochromic applications

导电织物因在智能服装、电极材料和柔性传感器等领域具有广泛的应用而备受关注.本研究采用多酚修饰法,利用单宁酸改性和化学镀银相结合的方法,制备了高导电的涤纶镀银织物(方阻为9.28 mΩ/□).与传统的织物镀银工艺相比,该方法省去了敏化活化等步骤,具有工艺简单、节省成本和导电性能优异等特点.以高导电镀银织物作为电致变色器件的阴极,喷涂聚苯胺的ITO-PET薄膜为阳极组成电致变色织物器件,该聚苯胺电致变色织物器件具有丰富的色彩变化(黄绿色-深绿色-蓝黑色)、优异的循环稳定性(伏安循环3000次)、较低的变色电压(–0.8 V/1.8 V)和较快的变色速度(4.3 s/6.4 s)以及柔性轻质的特点,可广泛应用于军事伪装服、野外考察服、布型显示器以及民用时尚变色服装等领域.

Electrochromic fabric is an intelligent textile that relies on the electrochromic effect of materials and has broad applications in adaptive camouflage,biomimetics,and flexible wearable color-changing clothing.Currently,the dominant fabrication processing methods involve either preparing flexible electrochromic fibers before weaving them into electrochromic fabric,which is complicated and difficult to incorporate into clothing,or using conductive fabric as an electrode and then assembling a large area electrochromic fabric device by combining electrochromic films.The latter method allows for the use of soft and non-transparent conductive fabrics as electrode materials,which broadens the choice of electrode materials and facilitates the preparation of large-area electrochromic fabrics.In this study,we redesigned the structure of the electrochromic device by incorporating highly conductive silver-plated fabric as the opposite electrode to facilitate electron conduction and an ITO-PET film with a polyaniline coating as the working electrode for electrochromism.Using a PMMA-based gel electrolyte,we assembled an all-solid-state electrochromic fabric device.Our results showed that the electrochromic properties and cycle stability of the electrochromic fabric devices were significantly enhanced.To prepare the conductive fabric,we obtained polyester silver-plated fabric via a sequential process of oil removal coarsening,tannic acid modification,silver nitrate pretreatment,and electroless silver plating.The adhesion of tannic acid enhanced the binding force between the silver layer and polyester,addressing the problem of low reactivity on the fabric surface due to the lack of active groups,which impedes the coating of silver onto the fabric surface.Furthermore,by utilizing the reducing property of tannic acid,the catalytic layer of silver particles can be obtained on the fabric surface,which successfully replaces the sensitization and activation step in the conventional electroless silver plating process.The as-prepared conductive fabric features a uniform and dense surface silver layer,excellent electrical conductivity(9.28 mΩ/□),good adhesion properties,and high heat and friction resistance.For the polyaniline electrochromic materials,we synthesized them using the chemical oxidation method,with aniline as the monomer,sulfamic acid and hydrochloric acid as the doping acids,and ammonium persulfate as the oxidant.We then prepared polyaniline films via a spraying process.The film exhibited exceptional electrochromic properties,including high optical modulation amplitude(63% at 740 nm),fast response time(2.4 s for coloring and 5.8 s for bleaching),high coloring efficiency(127.9 cm~2C~(-1)),and prolonged cycle life(5000 cycles).Finally,we assembled an all-solid-state electrochromic fabric device using the polyaniline film as the working electrode and highly conductive silver-plated fabric as the opposite electrode.The as-fabricated polyaniline electrochromic fabric device exhibited a diverse range of color changes(yellow-green to dark green to blue-black) and possessed excellent cycling stability(3000 cycles),low color-changing voltage(1.8 V for coloring,–0.8 V for bleaching),and fast colorchanging speed(4.3 s for coloring,6.4 s for bleaching).It also had the characteristics of flexibility and lightweight,which make it suitable for direct applications in military camouflage uniforms,field expedition clothing,cloth-type displays,as well as civilian fashionable color-changing clothing and other fields.