The chemical analysis and replication of polydimethylsiloxane by-products located within electrical trees

We present a spectroscopic study of electrical trees grown in polydimethylesiloxane (PDMS) rubber. Electrical trees were grown at a range of voltages and allowed to propagate throughout the material. Breakdown and tree channels were exposed using cryogenic microtoming. Raman microprobe spectroscopy (RMS), Fourier Transform Infrared (FTIR), and X-ray Photoelectron Spectroscopy (XPS) were applied in order to obtain a detailed spectroscopic analysis of electrical treeing and breakdown in PDMS rubber. For comparison, a selection of liquid systems including PDMS oil, dodecylbenzene (DDB) and dodecane (DD) were subjected to ageing via electrical discharges between two electrodes. The debris subsequently formed was subjected to spectroscopic analysis as before. Results are discussed in comparison to previously published results involving electrical treeing and corona discharge experiments in polyethylene (PE) and PDMS rubber.