Surface diffusion of poly(ethylene glycol) (PEG) as a function of increasing confinement is described. PEG is allowed to diffusion on a model surface bounded by poly[oligo(ethylene glycol)methyl ether methacrylate] (POEGMA) "walls". As the size of these "corrals" decrease, i.e. increasing confinement, a new mode of PEG surface diffusion is observed. The design of this compartmentalized model system for the investigation of diffusional transport in nanosystems is described. The arrays of corrals confined by POEGMA ”walls” were fabricated using double-exposure interferometric lithography to deprotect aminosilane films protected by a nitrophenyl group. In exposed regions, removal of the nitrophenyl group enabled attachment of an initiator for the atom-transfer radical polymerization of end-grafted POEGMA (brushes). Diffusion coefficients of PEG of different molar mass in these corrals were obtained by fluorescence correlation spectroscopy. Two modes of surface diffusion were observed: one which is similar to diffusion on the unpatterned surface and a very slow mode of surface diffusion that becomes increasingly important as confinement increases. Diffusion within the POEGMA brushes does not significantly contribute to the results.

Appearance of a slow mode of polymer surface diffusion on polymer brush-patterned surfaces in aqueous solution

2019 Fall National Meeting

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