Dielectric behaviour and relaxation processes of montmorillonite clay nano-platelet colloidal suspensions in poly(vinyl pyrrolidone)-ethylene glycol oligomer blends

• Published in: Polymer international 2009-07, Vol.58 (7), p.781-789
• Main Authors: Sengwa, Ram Jeewan, Choudhary, Shobhna, Sankhla, Sonu
• Format: Article
• Language: English
• Subjects: Applied sciences; Composites; dielectric spectroscopy; electrical conductivity; Exact sciences and technology; Forms of application and semi-finished materials; MMT clay nano-platelet colloidal suspension; Polymer industry, paints, wood; PVP-EGO blends; relaxation time; Technology of polymers
• ISSN: 0959-8103; 1097-0126
• DOI: 10.1002/pi.2592

BACKGROUND: Intercalated and exfoliated montmorillonite (MMT) clay structures in polymer matrices improve the thermal, mechanical, electrical and pharmaceutical properties of organic–inorganic materials. Poly(vinyl pyrrolidone) (PVP)–ethylene glycol oligomer (EGO) blends are biocompatible and non‐toxic materials. The dielectric characterization of MMT clay nano‐platelet colloidal suspensions in PVP–EGO blends is important in understanding the ionic conduction behaviour in many complex phenomena occurring in biological systems, and in selective membranes and their use in controlled drug release systems and in liquid electrolytes. RESULTS: An investigation using dielectric spectroscopy in the 20 Hz to 1 MHz frequency range of MMT clay nano‐platelet colloidal suspensions in PVP–EGO blends confirmed that the PVP segmental motion, ionic conduction relaxation time, electric double layer relaxation time and direct current electrical conductivity are significantly influenced by the clay concentration and EGO chain length. In these materials, ionic motion and PVP segmental dynamics are strongly coupled. Intercalation of EGO structures in clay galleries and exfoliation of clay platelets by adsorption of PVP–EGO structures on clay surfaces are governed by hydrogen bonding interactions between the carbonyl groups of PVP monomer units, the hydroxyl groups of EGOs and the hydroxylated aluminate surfaces of the MMT clay. CONCLUSION: The dielectric behaviour of intercalated and exfoliated structures of MMT clay nano‐platelet colloidal suspensions in PVP–EGO blends provides a convenient way to obtain liquid organic‐inorganic polymeric nanocomposite electrolytes with tailored ionic conduction properties. Copyright © 2009 Society of Chemical Industry