Peter Yin Kwai Lo

Siloxane Materials for Optical Applications

Siloxanes, which can be viewed as hybrids of glass and organic materials, have been used to fabricate polymer waveguides and devices that exploit the large thermo-optical effect of this material. Siloxanes have many unique properties including good thermal stability, chemical resistance, tunable refractive index, tunable mechanical properties and excellent photo-stability. The refractive index of siloxane polymer is composition dependent and generally ranges from 1.4 to 1.54. Introduction of porosity or composition modification can further expand refractive index range to 1.15~1.63. The loss and absorption characteristics for a variety of silicone-based polymers are examined and an example of a UV curable polymer coating illustrates the flexibility of the silicone polymer family to be tailored to meet specific application needs.

Platinum-catalysed isomerisations of 1,2-disilylhex-1-enes

(E)-2-Butyldimethylsily-1-trimethylsilylhex-1-ene 1 and (E)-1-butyldimethylsilyl-2-trimethylsilylhex-1-ene 4 undergo platinum-catalysed isomerisation reactions with migrations of carbon-carbon double bonds to form (E)-and (Z)-1,2-disilylhex-2-enes at elevated temperatures. The reactions proceed under nitrogen but not under dry air. The structures of the products were determined using 1H, 29Si, two-dimensional 1H-29Si, and selectively decoupled 29Si NMR techniques.