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Surface potential decay of PMMA and POM in air
Date Issued
01-04-2015
Author(s)
Tewari, Somesh Vinayak
Chandra, Romesh
Sharma, S. K.
Indian Institute of Technology, Madras
Sharma, Archana
Mittal, K. C.
Abstract
Perspex (polymethyl methacrylate (PMMA)) and delrin (polyoxymethylene (POM)) are subjected to high voltages and then the surface potential decay is measured using an electrostatic voltmeter. The surface trapping parameters ofPMMAare calculated using isothermal current theory and a plot between trap density and energy level is obtained. It is observed that the maximum electron and the hole traps in the surface layer of PMMA are ∼1.5 × 1017 eV-1m3 and 0.8 × 1017 eV-1m3, respectively, and the energy level of its electron and hole traps are in the range of 0.60-0.90 eV and 0.78-0.9 eV, respectively. The introduction of roughness onPOMsurface leads to an increase in the energy level from 0.55-0.87 eV to 0.55-0.89 eV. It is also observed that there is an increase, both in peak surface potential and time to decay inPMMAas compared to POM. This holds true for positive as well as negative dc voltages and is caused by the charge retentivity in the material resulting from the length of the polymeric chain.
Volume
2