(326h) Interfacial Surface Energy Study of the PVC/TiO2-HNTs Ultrafiltration Membrane for Its Suitability As an Antifouling Membrane

Gourav Mishra and Mausumi Mukhopadhyay^*

^*Department of Chemical Engineering Sardar Vallabhbhai National Institute of Technology, Surat, Gujarat India-395007

Abstract

The present work describes the study of polar and apolar liquids for the determination of the interfacial surface energy of the titanium dioxide loaded halloysite poly(vinyl chloride) (PVC/TiO₂-HNTs) ultrafiltration (UF) membrane. With the help of a classical phase inversion method, PVC/TiO₂-HNTs UF membrane was prepared by blending TiO₂-HNTs nanofiller in different concentrations (0-3wt%). For the determination of hydrophilicity and surface tension elements of the PVC/TiO₂-HNTs UF membrane, contact angle goniometer instrument was used. glycerol (polar), pure water (polar) and diiodomethane (apolar), with known surface tension properties, were used to calculate solid-liquid free energy of the polymeric membrane with the help of modified Young-Dupre equation. The pure water contact angle of PVC/TiO₂-HNTs 0 (0wt%) was 82.41^áµ’ whereas it was 68.81^áµ’ for PVC/TiO₂-HNTs 3 (3wt%). Low contact angle reflects better hydrophilicity and signifies that with an increase in TiO₂-HNTs nanofiller content (0-3wt%), membrane hydrophilicity also increased. To study the membrane surface energy and surface morphology characteristics, solid-liquid interfacial free energy were also calculated as the water contact angle measurement data alone was insufficient to explain the wetting ability of the membrane. Higher the surface energy of the membrane higher was its hydrophilic nature and vice versa. The surface energy parameter reflects the capacity of all membranes to donate an electron (γ^-) and possess comparatively less electron acceptability (γ⁺). Furthermore, total interfacial free energy ( value) of PVC/TiO₂-HNTs 2 (2wt%) was -26.15 mJ/m² and for PVC/TiO₂-HNTs 0 membrane it was -61.08mJ/m². These values showed that the PVC/TiO₂-HNTs membrane possess higher total liquid surface tension as compared to PVC/TiO₂-HNTs 0. -∆G_SL (wettability) reflects that the addition of TiO₂-HNTs increases the interfacial free energy from 82.19 to 98.22 mJ/m² for PVC/TiO₂-HNTs 0 and PVC/TiO₂-HNTs 3, respectively with a decrease in surface roughness. Thus the TiO₂-HNTs nanofiller showed the potential to significantly improve membrane hydrophilicity as well as surface energy for antifouling polymeric membrane preparation.

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