Effect of macromolecular anchoring layer thickness and molecular weight on polymer grafting

Carboxylic acid-terminated polystyrene (PS) of different molecular weights from 4500 to 672 000 was grafted from melt onto silicon substrates modified with a macromolecular anchoring layer. The study was focused on influence of thickness and molecular weight of the layer on the permanent attachment of the end-functionalized PS layers by the "grafting to" approach. Poly(glycidyl methacrylate) (PGMA) was used to form the reactive anchoring interface. The grafting trends observed and the amount of PS anchored were not significantly affected by the thickness and molecular weight of the anchoring layer, except for the case of lower molecular weight PS (4500 g/mol). The higher grafting in the latter case may be a result of formation of an extremely extended interphase between loops of the adsorbed PGMA and the low molecular weight PS.