Effects of acid treatment at different temperatures on the surface dielectric properties of low-density polyethylene

The surface dielectric properties of acid-etched low-density polyethylene (LDPE) were analysed in the frequency range from 20 Hz to 200 kHz. Samples were treated with various acids for a period of one hour, at temperatures ranging from 20 to 70 degrees C. After the treatment, the samples were analysed with Fourier transform infrared spectroscopy, revealing chemical and crystallinity changes on the surface, as a direct result of the treatment. The sample surfaces were analysed using atomic force microscopy. The micrographs show that the acid treatment increases the roughness of the samples. Compared to untreated LDPE, the etched samples may exhibit significantly different conductance values at low frequencies. It is also observed that an increase in the acid treatment temperature can result in lower values of conductance and susceptance compared to untreated samples. LDPE films with low value of surface AC conductivity after acid treatment are potentially useful substrates for high-speed electro-sensing applications. The presented results indicate that a suitable choice of acid treatment of LDPE can effect surface polarization while preserving low values of surface AC conductivity of the polymer. (c) 2014 Society of Chemical Industry