State analysis of dissolved water in polydimethylsiloxane by FT-IR spectroscopy and effects of water clusters on conduction phenomena

The state of dissolved water in polydimethylsiloxane (PDMSi) was studied by FT-IR spectroscopy at 20 degreesC, and the thermal depend dependence of di ssolved water in PDMSi was examined. The state was compared with some low m olecular weight siloxane and ether compounds. The effect of water clusters in PDMSi on conduction phenomena was also studied. In PDMSi, the water clus ters mainly consisted of small clusters such as a monomer-like dimer (hydra ted water molecule with oxygen atom in siloxane polymer). The number of lar ge clusters that formed around ether group in PDMSi was very small in contr ast to those in other siloxane and ether compounds. The small water cluster existed stably in PDMSi against heating until 180 degreesC better than any other clusters. Dissolved water did not enhance conductivity until 180 ppm But when the amount of dissolved water exceeded 180 ppm, the conductivity remarkably increased. It was found that monomer like dimer mainly contribut ed to the increase in the conductivity.