Hybrid molecular brushes with chitosan backbone: facile synthesis and surface grafting

We developed a facile route toward amphiphilic hybrid molecular brushes (HMB) with chitosan backbone and concurrently grafted chains of poly(acrylamide) and polystyrene. The grafting occurs through amino groups of chitosan; no extra modification of chitosan is required. The kinetic and molecular weight characteristics of the primary molecular brush CHI-graft-PAAm are studied. The second step is grafting of PS by emulsion polymerization. The resulting HMB CHI-graft-PAAm-graft-PS form very stable emulsions. We attached the HMB on solid substrates using chitosan backbone by the "grafting to" approach. Thin films of the immobilized HMB of 3-11 nm thickness completely cover the surface. Being amphiphilic by nature, the immobilized HMB reveal the ability to adapt to the medium, which results in shifting of the hydrophobic/hydrophilic balance over a wide range.