Grafting of amphiphilic block copolymers on lignocellulosic materials via SI-AGET-ATRP

Functionalizing biosourced materials is a major topic in the field of materials science. In particular, grafting polymerization techniques have been employed to change the surface properties of various substrates. Here, we report on the grafting of amphiphilic block copolymers in lignocellulosic materials using surface-initiated activators generated by electron transfer atomic transfer radical polymerization (SI-AGET-ATRP). With this modification, it is possible to combine the interesting properties (anisotropy and high mechanical stability) of lightweight lignocellulosic materials, such as wood, with the special properties of the grafted block copolymers. Hydroxyl groups on wood cell wall biopolymers were used for the chemical bonding of an alkyl bromide as the initiator for AGET-SI-ATRP of a highly hydrophilic monomer ([2-(methacryloyloxy)ethyl]trimethylammonium chloride) and a highly hydrophobic fluorinated monomer (2,2,3,3,4,4,5,5-octafluoropentyl methacrylate). The successful grafting of homopolymers and block copolymers onto the wood structure was confirmed through Fourier transform infrared and Raman spectroscopy. The functionalization with the two homopolymers yielded lignocellulosic materials with opposite wettabilities, whereas by the adjustment of the ratio between the two copolymer blocks, it was possible to tune the wettability between these two extremes. (c) 2019 Wiley Periodicals, Inc.