Preparation of Functional Stimuli-responsive Polyamide 6 Fabric with ZnO Incorporated Microgel

A new functional, stimuli-responsive microgel coating on polyamide 6 (PA6) fabric with simultaneous temperature (T)- and pH-responsive moisture management, UV protection and photocatalytic self-cleaning properties was prepared by applying poly-(N-isopropylacrylamide)/chitosan (PNCS) microgel in combination with ZnO nanoparticles to PA6 fabric. Two different application procedures were used: (i) the application of PNCS previously functionalized with a ZnO nanoparticles suspension and (ii) the application of PNCS with the subsequent application of a ZnO nanoparticles suspension. The coatings were fabricated on the untreated PA6 fabric as well as on fabric previously modified by the silica matrix created by the sol-gel precursor iSys MTX in order to increase the adsorption ability and uniformity of the coating. The chemical and morphological properties of the coated PA6 samples were determined by SEM and FTIR analyses. Stimuli responsiveness and functional properties were assessed by the moisture content, water vapour transmission rate, water uptake, UV protection and photocatalytic self-cleaning measurements. The results show that the application procedure as well as the pretreatment of PA6 fabric greatly infl uenced the properties of the coating. Accordingly, the most appropriate procedure included the creation of a silica matrix on the PA6 fibres followed by the application of PNCS and subsequent application of ZnO. In this case, the modified PA6 fabric exhibited high T and pH responsiveness due to the swelling/de-swelling activity of the PNCS microgel, as well as good UV protection with UPF equal to 18.8 and photocatalytic self-cleaning properties that are even higher than those in the case of the one-component coating with ZnO