A study of the structure and formation of biocompatible mesostructured polymer- surfactant hydrogel films

Abstract

The aim of this work has been to investigate the formation of films and to couple their properties with the bulk behaviour of the film forming components. The primary goal was to improve the biocompatibility of the films, as films are of great interest to the biomedical industry. The investigated films form spontaneous at an air-water interface and some are robust enough to be removed from the surface. The films are formed by mixed surfactants of the cationic CTAB and the zwitterionic SB3-14 together with the polymer PEI, in a short and long form. The film structures are investigated with varying  CTAB:SB3-14 ratio. It was found replacing CTAB with SB3-14 reduced mesostructure in the films, however when PEI was used to form the films in its long form there was sufficient polymer network to kinetically trap mesostructure in the films. To increase biocompatibility, CTAB was replaced with calcium chloride to emulate the cationic charge and present opportunites for complex formation with the polymers. SB3-14 was still present as the surfactant to impart mesostructure with PEI as the polymer. Here it was found that mesostructure could be controlled with calcium chloride concentration due to its hygroscopic nature modulating the amount of water in the films and therefore the resulstant mesophases. Finally, anionic biopolymers were investigated with the spray coated films. Here it was found that they complexed with calcium chloride more fully than PEI and thus the competition between calcium chloride and SB3-14 for water resulted in more hydrated mesophases than when PEI was used as the film forming polymer. The bulk solutions and films were investigated mainly with small angle scattering and reflectivity techniques. It was found that as a progression to previous work in the research group that more biocompatible methods could be used to form structured films.

Date of Award	26 Feb 2014
Original language	English
Awarding Institution	University of Bath
Supervisor	Karen Edler (Supervisor)