Photoinduced grafting-from method

Surface photografting methodology 10.2.1. Photoinduced grafting-from method 

Numerous investigations have described the photoinduced modification of polymeric substrates with the use of commonly used benzophenone (BP) and derivatives, ketones or aldehydes, hydrogen peroxide, photoiniferters and, more recently, triarylsulfonium salts (TAS). 

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This chapter first reviews the various techniques to perform the surface photografting modifications (according to the grafting-from and grafting-to methods) and all the photoinduced mechanisms involved in these processes. Finally the achievements of the photoinduced modified materials are summarized, wherein the enhancement of wettability, adhesion and some useful applications are reported. Examples are mainly focused on polyester substrates. 

The first approach for cellulose modification followed in the Bamer-Kowollik team employs the photoinduced functionalization of photoinitiator-modified substrates with preformed raYrax/cfe-functionalized macromolecules, which are derived from commercially available photoinitiators and nitroxides [DEL 12a]. The approach is based on the generation of radicals at the cellulose surface by mild UV irradiation (5 -max 311 nm) of an immobilized photoinitiator, followed by radical trapping with a nitroxide species. To evaluate the new photochemical grafting method, preliminary studies were carried out based on the nitroxide end functionalization of PEG in solution. Moreover, the light-induced radical technique was used to eouple two synthetie maeromolecular strands. 

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