The surface composition of polymer films plays a pivotal role in tailoring surface properties such as wettability, adhesion, friction, and biocompatibility. Surface composition of polymeric systems can be controlled via the segregation of low energy components to the polymer surface. Several flexible polymer systems exhibit segmental density distribution due to the localization of functional chain-ends to the polymer-air interface. This chain-end behavior can be used to dictate surface properties of polymer films but has yet to be investigated in rigid-rod polymer systems. This work investigates the surface and interfacial chain-end behavior in rigid rod polyethersulfone (PESU) films with different functional chain ends: hydroxy and fluorescein isothiocyanate (FITC). Commercial PESU was fractionated and characterized via static and dynamic light scattering. Depth profiles of chain-end distribution in solution cast films was investigated using grazing angle ATR-FTIR, X-ray photoelectron spectroscopy (XPS) with ion gun etching (see figure), and fluorescent labeling. Finally the resulting surface properties were studied using contact angle and atomic force microscopy in both lateral force mode and quantum nanomechanical mapping mode. Experimental results were combined with molecular dynamics simulations to construct an overall model of chain-end distribution in rigid rod systems.

Controlling surface composition and properties of polyethersulfone films through chain-end chemistry

248th National Meeting (2014)

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