Date of Award

Fall 2014

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Materials Science and Engineering - (Ph.D.)

Department

Committee for the Interdisciplinary Program in Materials Science and Engineering

First Advisor

John Francis Federici

Second Advisor

Zafar Iqbal

Third Advisor

S. Mitra

Fourth Advisor

Robert Benedict Barat

Fifth Advisor

Cristiano L. Dias

Abstract

The thermochromism and chemochromism of polydiacetylene (PDAs) and PDA/ZnO nano composites have been systematically studied by attentuated total reflection (ATR)- Fourier transform infrared (FTIR), temperature-dependent Raman, colorimetric (using optical densitometry) and differential scanning calorimetry (DSC). Reversibility of PDAs has been enhanced by the formation of chelation between the carboxylic groups on side chain of diacetylene and Zn ion. The thermochromatic transition temperature increases with the concentration of ZnO.

Thin films of polydiacetylene (PDAs) and PDA/ZnO nanocomposites have been successfully fabricated by inkjet printing both solution type and suspension type ink. Results suggest that PDA monomers are well-aligned and closely packed following printing. By modifying the particle size of PDA monomers or the diacetylene/ZnO particle size, reversible PDA ink with wider range of ZnO concentration and longer shelf life could be obtained by using water based ink. Also, with inkjet printing technology, thin film of PDA and PDA/ZnO composites could be deposited on different substrate materials, such as paper, Kapton and Mylar film.

In order to further study alkyl side chain effect on the sensitivity of PDA, Density Function Theory (DFT) simulation is conducted, and the results show that the torsion of C-C bond is closely related to the length of the alkyl side chain.

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