Carbinol (Hydroxyl) Terminated Polydimethylsiloxane, Mw 7000 - 8000

Sakurai, Shinichiro, Hirohmi Watanabe, and Atsushi Takahara. Polymer journal 46.2 (2014): 117-122.

Carbinol (hydroxyl) terminated polydimethylsiloxane (PDMS) was anchored to a silicon substrate using triethoxysilyl terminal units. Atomic force microscopy showed that the linear polymer brushes provided a rough surface in water. Since water is a poor solvent for PDMS, the linear polymer brushes tend to be dewetted and form aggregates. In contrast, the surface of the cyclic polymer brushes is smooth in air and water.
The researchers added 3-isocyanatopropyltriethoxysilane (300 mg, 1.2 mmol) to carbinol (hydroxyl) terminated PDMS (1.01 g, 0.091 mmol, M: 11 100, M/M: 1.88) and stirred the mixture vigorously at 45°C. A catalytic amount of 4-dimethylaminopyridine was added to the solution and the reaction mixture was stirred at 45°C overnight. After the reaction mixture was cooled to room temperature, the crude product was washed with acetonitrile (2 ml × 5), and the product was dried in vacuo at room temperature overnight to remove all volatiles and collect the colorless oil with two triethoxysilyl terminal units (Poly-H) (0.90 g, 85%). Low molecular weight PDMS (Poly-L) with two triethoxysilyl terminal units, high molecular weight PDMS (Poly-H) with triethoxysilyl terminal units, and low molecular weight PDMS (Poly-L) with triethoxysilyl terminal units were synthesized according to a similar method. The amount of 3-isocyanatopropyltriethoxysilane was fixed to be greater than 6 equivalents.