DEGRADATION OF A THIN POLYMER FILM STUDIED BY SIMULTANEOUS IN-SITU ATOMIC FORCE MICROSCOPY AND SURFACE-PLASMON RESONANCE ANALYSIS

A new in situ method of analyzing changes occurring to polymeric surfa ces has been generated by the combination of atomic force microscopy ( AFM) and surface plasmon resonance (SPR) in a novel instrument which c an simultaneously acquire data from these two techniques. The applicat ion of this;instrument provides new insights into the dynamic changes occurring to a thin biodegradable polymer film when the surface of thi s film is exposed to a hydrolyzing environment. The AFM data enable th e visualization of the topographical changes that result from degradat ion, whilst the SPR monitors the kinetics of the removal of polymer ma terial from the film surface. The degradation of a spun cast thin film of a poly(ortho ester) is analyzed in this study. The,combined AFM/SP R data record the erosion of the thin film on the SPR sensor as degrad ation progresses. The pH sensitivity of the hydrolysis of the poly(ort ho ester) film is explored by dynamically altering the pH during degra dation to highlight the sensitivity of the instrument in the quantific ation of the degradation process.