Surface composition control via chain end segregation in polyethersulfone solution cast films

Abstract

Surfaces and interfaces of polyethersulfone (PESU) materials play a crucial role in the overall performance of the polymer in applications such as filtration membranes, medical devices, and protective coatings. This work investigates the chain end localization to the polymer-air interface of solution cast films of semi-rigid rod PESU polymers end-capped with phenol (OH) and fluorescein isothiocyanate (FITC) groups. PESU solutions of varying molecular weight and low distribution were characterized via gel permeation chromatography (GPC) as well as static and dynamic light scattering. X-ray photoelectron spectroscopy (XPS) and confocal laser microscopy revealed a preferential localization of both –OH and –FITC chain ends to the PESU-air interface. Scaling of the chain end concentration as a function of polymer dimensions was determined to differ from that of flexible chain polymers. Surface analysis demonstrated that chain end chemistry could be used to tailor the nano- and macro-scale properties of the resulting PESU surface.