Events

Thesis Title: Cellulose Nanocrystal Coated Paraffin Wax Coating for Fog and Dew Water Harvesting

Abstract:

Fresh water scarcity is an urgent global issue. A sustainable and renewable method is harvesting atmospheric water, among which fog and dew water can be passively collected onto a surface. The efficiency of such collecting systems depends critically on the wetting and dynamic behavior of water droplets on the surface. Common approaches to modify surface topography and hydrophobicity often relies on lithographic, plasma, or fluoropolymer-based methods that are costly, complex, and environmentally unsustainable. In contrast, this work proposes a novel, simple, and bottom-up approach for producing surface with functional coatings through cellulose nanocrystal (CNC)–stabilized Pickering emulsions.

The widespread adoption of thermoset nanocomposites has created significant end-of-life management challenges due to their permanent crosslinked networks, which resist conventional recycling methods and trap valuable nanomaterials within non-degradable matrices. This work presents a proof-of-concept study to assess a new approach for achieving a circular economy for thermoset nanocomposites; recovering and reusing nanomaterials from thermoset nanocomposites through the incorporation of cleavable comonomers into the polymer matrix, enabling controlled matrix degradation and nanofiller recovery at end-of-life.

Carbon nanotubes (CNTs) were selected as the nanofiller for this study due to their widespread use in nanocomposites and growing industrial significance, and a styrene/divinylbenzene (DVB) thermoset matrix was chosen as a model matrix for its chemical compatibility with CNTs. To enable controlled degradation at end-of-life and nanofiller recovery, comonomer additives that can install cleavable bonds into the matrix’s polymer network were systematically evaluated. Several candidates were investigated, including cyclic ketene acetal (CKA) (specifically 2-methylene-1,3-dioxepane, MDO), which underwent hydrolysis too rapidly and an unwanted ring-retaining side reaction for practical application, and thionolactones (specifically dibenzo[c,e]-oxepine-5(7H)-thione, DOT and 2-(isopropylthio)dibenzo[c,e]oxepine-5(7H)-thione, 2SiPrDOT), which was limited by the monomers’ solubility in the styrene/DVB system. Through this careful screening process, 2SiPrDOT was selected as the most suitable option, offering both chemical stability during processing and sufficient solubility in the system.

Influence of Cellulose Nanocrystals and Surfactants on Catastrophic Phase Inversion and Stability of Emulsions