Polydimethyl Siloxane - Urethane

So far in this chapter on sequencing, two techniques have predominated NMR spectroscopy and Py-GC. An exception is the work of Zhuang and co-workers [67] who used ToF-SIMS in their study of the distribution of polydimethylsiloxane (PDMS) segment lengths at the surface of PDMS-urethane-segmented copolymers. Their aim was to establish whether, at the copolymer surface, the distribution of segment or chain lengths is different from that in the bulk of the polymer. 

SIMS has been emerging as a potential tool, particularly with ToF detection technologies. ToF technologies can yield increased resolution, mass range, and transmission. 

Based on the assigned fragment structure, the length distribution (relative intensities versus m values) was constructed. It was calculated that M = 1131.1, = 1171.4, 

By comparing the low-mass (m/z = 0-300) spectra from the submonolaye m/z PDMS prepolymer film on Ag and the thick PU-PDMS copolymer film on Al, it was noted that the PDMS segment compositionally dominated the surface of the thick PU-PDMS film. This observation agrees well with earlier electron spectroscopy for chemical analysis (ESCA) results. 

In addition, by comparing the low-mass (m/z = 0-300) spectra from the submonolayer PDMSO prepolymer film on Ag and the thick PU-PDMSO copolymer film on Al, it 

---

B. Boutevin, L. Abdellah, M.N. Dinia, Synthesis and applications of photocrosslinkable polydimethyl siloxanes— Part III. Synthesis of polysiloxanes with perfluorinated and acry-lated urethane linked pendant groups, Eur. Pol. J.31 (11) (1995) 1127-1133. 

---