Incorporation and deposition of materials with chromism properties for sensing applacation

Abstract

This thesis deals with two topics: 1) surface deposition of diacetylene and leuco dye and 2) techniques for incorporation of leuco dyes into commercial polymers. For surface deposition, three techniques i.e. inkjet printing, airbrush painting and dip coating are evaluated. These three techniques can be used to deposit diacetylene monomers (PCDA and TCDA) onto surface of various solid materials with different advantages and limitations. While the ink-jet printing is good for deposition with computer-aided designed patterns on surfaces of thin sheet materials, the airbrush painting can give more intense color and more convenient to be used in the early development stage due to its greater operating flexibility and hassle-free ink formulation in comparison with the ink-jet technique. The dip coating is the most simple deposition technique to be used in the earliest step for the development of humidity indicators. With the subsequence use of airbrush painting, the time-humidity indicator prototypes are successfully developed. For the incorporation of leuco dyes into commercial polymers, three techniques i.e. melt spinning, compression molding and two roll mill processes can be used. The commercial thermochromic Chameleon-T powder is incorporated into several commercial polymers with retained reversible thermochromic properties. Various dye contents of 2, 3 and 5% can be incorporated into PP fiber filaments, LDPE, PP and PS plastic plates and SBR rubber plates by the melt spinning, compression molding and two roll mill combined with compression molding process, respectively. However, further investigation is required to optimize these incorporation techniques before they can be used in preparation of real temperature sensing plastic products.