Organic photochromic compounds (OPCs) are considered as a class of light sensitive compounds that undergo reversible structural transformation of their physicochemical properties (i.e., polarity and charge distribution) upon light irradiation as an external stimulus. These compounds have been extensively studied for decades, and are used in various applications such as biomedicine, chemical sensors and harvesting solar energy. In this thesis, applications of OPCs were investigated under two different projects: 1) controlling wettability of flat and microstructured gold surfaces and 2) controlling the electrical conductivity of polyaniline. The first project demonstrates how photoactive compounds can be used to tune the surface chemistry, surface free energy, and the wetting velocity of fluids on Spiropyran (SP) functionalized surfaces in different microstructured surfaces. In this regard, the wettability was measured using static and dynamic (advancing and receding) contact angles in microstructured surfaces conjugated SP. This study examined the possibility of reversible switching between the static Cassie-Baxter (or Wenzel) state and the dynamic hemiwicking state. Furthermore, by incorporating changes in contact angle into the Owens-Wendt and Van Oss surface energy models, the energy of smooth Au surfaces was predicted upon photoisomerization of SP. The second project investigated the possibility of photoswitching the conductivity of flexible films based of polyaniline (PANI). The film is composed of a visible light sensitive mixture drop casted on the Polyethylene terephthalate (PET) substrate precoated with a conductive polyaniline emeraldine salt (PANI-ES) layer. The electrical conductivity of the film is modulated by metastable state photoacid (mPAH), which is visible light induced proton transfer compound.
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Chumbimuni Torres, Karin
Doctor of Philosophy (Ph.D.)
College of Sciences
Length of Campus-only Access
Doctoral Dissertation (Open Access)
Haghighat Mesbahi, Ali, "Tuning the Fluid Wetting Dynamics on Gold Microstructures and Conductivity of Polyaniline Using Photoactive Compounds" (2022). Electronic Theses and Dissertations, 2020-. 1017.