Nanoscale versus Microscale Gelation for Crosslinked Polyurethanes

Abstract

In analyzing morphology of modified surfaces it is important to distinguish between features attributable to the matrix and those for the modifier. This study focused on an examination of the surface morphology of closely related linear and network polyurethanes intended for use as bulk coating constituents. A process dependent morphology is found for the crosslinked polyurethane matrix. Microscale gelation was found when reagents were added simultaneously, while nanoscale gelation occurs when the cross‐linker is added last. Furthermore, the coating formed by sequential addition had 50% less extractables. Future work on modified networks will focus on the matrix with nanoscale gelation as it presents a “cleaner” canvas for surface modification.