Relaxation of a Rubbed Polystyrene Surface
Author(s): Schwab, Alexander D., Ali Dhinojwala
Journal: Phys. Rev. E. Stat. Nonlin. Soft Matter Phys. (2003) 67(21): 21802(1-10).
Abstract:
The relaxation dynamics of a rubbed polystyrene (PS) surface have been characterized using infrared-visible sum frequency generation spectroscopy (SFG). The SFG results were compared with previous relaxation of retardation measurements, and the results show that the rubbed PS surface has the same Tg as the bulk where Tg is defined as τ(Tg) = 5 s, however, the surface has a lower activation energy (∆E) and a larger stretching exponent (βKWW) than bulk PS. This indicates that the surface region relaxes more quickly than the bulk. The thickness of this region of lower ∆E and larger βKWW is estimated to be roughly 12 nm.