We report on synthesis of a new type of highly swellable ultrathin cationic hydrogel with pH-triggered swelling behaviour and surface wettability. The single-component poly(4-vinyl pyridine) (P4VP) hydrogel films are produced by selective cross-linking of P4VP copolymers in layer-by-layer (LbL) films assembled via spin-assisted deposition. These multilayer hydrogels exhibit drastic and reversible 10-fold swelling when the pH is changed from neutral to acidic. The swelling amplitude of the hydrogels is controlled by varying cross-link densities within the films. These densities are varied by the number of cross-linkable amino-containing units in P4VP copolymer chains. We have found surface morphology of the hydrogels to be significantly affected by fabrication conditions. Contact angles vary from 70� to less than 10� for the films prepared from neutral and acidic solutions, respectively.  Our work opens new prospects for developing highly swellable stimuli-responsive nanothin hydrogels for sensing and transport regulation in microfluidic devices.

Highly swellable ultrathin multilayer hydrogels with pH-triggered surface wettability

247th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.