Dinâmica de umedecimento de fluidos em filmes de quitosana dopados com dansilas

Abstract

In this work, the wetting properties of chitosan samples doped with dansyl groups are investigated. Such an investigation is divided in two steps which analyze the sample properties on solid and fluid states. In the first step, it is characterized the wetting dynamics of doped and pure chitosan samples on solid substrates presenting distinct surface treatments: RCA protocol, cleaning with Extran solution and silanization. This study has the subject of identifying the most suitable treatment to produce chitosan films on solid substrates presenting conductance properties. In a second moment, it is verified the main modification induced by UV radiation on the wetting dynamics of fluids on doped chitosan films. In all cases, the wetting properties are analyzed by pendant drop and sessile drop goniometer techniques. The description of the main results are performed in the context of Molecular-Kinetic theory. The measurements show that surface treatments that induce the formation of hydroxyl are more suitable for the designing of eletroptical devices based on chitosan. Concerning the effects asssociated with the UV radiation, the results show that a change in the hydrophilicity of chitosan film doped with derivatives of dansyl groups. The main mechanisms governing the structural modification of films are discussed.