Towards light switchable surfaces

[摘要] ENGLISH ABSTRACT: Polymeric nanofibrous membranes that act as surfaces offer two compelling properties; they haveextremely large surface areas that can be modified and they can offer multiple reactive sites dependingon which polymer they were electrospun from. Combining nanofibrous surfaces such as these withphotochromic dyes can give remarkable, light responsive materials.In this study, a terpolymer was electrospun and crosslinked (to impart insolubility to the material) toproduce a nanofibrous mat that contained surface secondary-hydroxyl units and benzyl chloride units,from which monomers could grow using surface-initiated atom transfer polymerization (SI-ATRP).The surface was further fluorinated though the secondary-hydroxyl moieties to produce a hydrophobiccrosslinked nanofibrous surface.n-Butyl acrylate and a photochromic spiropyran dye were copolymerized from the surface using SIATRP,in order to produce a surface that exhibited reversible adhesion towards a water droplet usingultraviolet and visible light as a stimulus to change between the two states. This in principle wouldallow the droplet to roll off and stick to the surface respectively. Although the surface displayed acolour change when switched, proving that the SI-ATRP had taken place, the droplet of water remainedattached to the surface in both states.

[发布机构] Stellenbosch University