Surface Composition of a Series of Dimethylsiloxane Urea, Urethane Segmented Copolymers Studied by Electron Spectroscopy for Chemical Analysis
Abstract
Surface composition of a series of segmented poly(siloxane urea urethane)'s have been determined by angle- and energy-dependent ESCA. The polymers are based on aminopropyl end-capped dimethylsiloxane oligomers, isophorone diisocyanate and 1,4-benzene dimethanol. Effects of segmental length and annealing on the surface composition were investigated. It was found that when the average molecular weight of the siloxane segments reaches 27K, the topmost surface region (within 18 A of the free surface) of a film cast from tetrahydrofuran solution is nearly siloxane phase. To achieve a comparable degree of surface phase enrichment in films of copolymers with siloxane segmental molecular weight of 10K, annealing at 120 deg C for 15 minutes was required. Depth profiles based on these data showed that in as-cast films a siloxane deficient phase several nanometers thick occurs beneath the siloxane surface layer. Annealing increases the thickness of both surface phases
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1994
- Accession Number
- ADA282872
Entities
People
- Joseph A. Gardella Jr.
- Tai Ho
- Xin Chen
Organizations
- University at Buffalo