Structural studies of plasma polymers obtained in pulsed dielectric barrier discharge of TEOS and HMDSO on nylon 66 fabrics

Abstract

Plasma-enhanced chemical vapour deposition of two monomers, namely tetraethylorthosilicate (TEOS) and hexamethyldisiloxane (HMDSO) was carried out on nylon 66 fabrics. Pulsed discharge at variable duty cycle was used for analysing the effect of different pulse parameters on the structural properties of plasma polymers. HMDSO plasma yielded more hydrophobic surfaces than TEOS plasma. The surface chemical composition of plasma-treated fabrics was investigated by Fourier transform infra-red spectroscopy. Both duty cycle and treatment time were found to play a substantial role in determining the structural properties of plasma polymers. Organic content, , of HMDSO plasma polymers (pp-HMDSO) showed comparatively better retention of the original monomer groups at shorter treatment durations and at lower duty cycles. TEOS plasma polymers (pp-TEOS) obtained under pulsed discharge exhibited higher carbon content when compared to continuous wave (CW) plasma. The effect of pulsed discharge conditions on the tensile properties was also investigated. A slight but significant increase in the elastic modulus of nylon fabric was observed after treatment with the HMDSO plasma under CW discharge. The durability of plasma polymers to washing demonstrated that HMDSO is superior to TEOS for obtaining hydrophobic surface with good durability in nylon 66 fabrics.