| dc.description.abstract | This work focuses on modifying active membrane of polymeric substrates using layer by layer coatings and laser induced graphene for hydrogen purification and carbon capture applications. Membranes offer an alternate solution for gas separation over the current industrial process including pressure swing adsorption and cryogenic distillation. Polymeric membranes owing to the cost-effective, energy efficient, and low carbon footprint operation can be used for gas separation applications, however, polymeric membranes have intrinsic trade-off between permeability and selectivity of the membrane.
This thesis focuses on two topics: a) Layer-by-layer (LbL) coatings on hollow fibers composed of poly amide imide (Torlon©), and b) laser-induced graphene (LIG) on polysulfone films. In LbL deposition process, alternate layers of polycationic and polyanionic polymers are deposited on a substrate to form highly cross-linked and inter-diffused layers. In this work, two polymeric pairs were investigated: (a) Polyethyleneimine (PEI) and polyacrylic acid (PAA) pair for hydrogen and, (b) Poly methacrylic acid (PMMA) and polyethylene oxide (PEO) pair for carbon capture. This work utilized the LbL technique to fabricate a new class of highly selective and composite polymer membrane on Torlon© based hollow fibers for hydrogen separation and carbon capture applications.
For laser-induced graphene/polysulfone membrane, CO2 laser was used to photothermally reduce the top surface of the polymeric film to LIG layer. Optimal parameters of laser were identified to get defect-free and reproducible membranes. The LIG/polysulfone membranes resulted in an improvement in the permeability and selectivity of the neat polysulfone film. | en |
