?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=http%3A%2F%2Fd-scholarship-dev.library.pitt.edu%2F37618%2F&rft.title=Development+of+2-Dimensional+Photonic+Crystal+Sensors+and+Pure+Protein+Organogel+Sensing+and+Biocatalytic+Materials&rft.creator=Smith%2C+Natasha&rft.description=We+developed+responsive+hydrogels%2C+organogels%2C+and+ionogels+for+chemical+sensing+and+catalysis+applications.+Gels+have+two+components%2C+polymer+networks+and+solvent+mobile+phases.+Hydrogels+contain+an+aqueous+mobile+phase%3B+organogels+an+organic+solvent%3B+and+ionogels+an+ionic+liquid.+Different+solvent+types+were+required+to+target+different+applications%2C+e.g.+gas+sensing+requires+solvents+that+resist+evaporation.+%0D%0AColorimetric+chemical+sensors+utilize+our+2-Dimensional+Photonic+Crystals+(2DPC)+technology.+2DPC+are+arrays+of+self-assembled+polystyrene+nanoparticles+that+have+close-packed%2C+hexagonal+crystal+structures.+2DPC+diffract+wavelengths+of+light+into+discrete+angles+according+to+the+2D+Bragg+equation.+Diffraction+depends+on+2DPC+particle+spacing+and+ordering.+2DPC%E2%80%94embedded+into+gels+that+were+designed+such+that+analytes+actuate+polymer+volume+phase+transitions+(VPT)%E2%80%94change+particle+spacing+with+the+VPT%2C+shifting+diffraction+angles.+VPT+occur+when+analytes+cause+Gibbs+free+energy+changes%2C+%E2%88%86G.+%0D%0A2DPC+surfactant+sensors+utilized+poly(N-isopropylacrylamide)+(PNIPAAm)+hydrogels.+PNIPAAm+hydrogels+swell+when+the+hydrophobic+tail+of+ionic+surfactants+bind+to+the+PNIPAAm+isopropyl+group.+A+Donnan+potential+created+by+bound+charges+induces+%E2%88%86GIonic%2C+causing+swelling+that+red+shifts+the+diffraction.++%0D%0A2DPC+gas+sensors+for+humidity+and+ammonia+utilized+poly(hydroxyethylmethacrylate)-based+polymers+in+the+ionic+liquid+ethylguanidinium+perchlorate+(EGP).+Ionogels+are+suitable+gas+sensors%E2%80%94ionic+liquids+have+negligible+vapor+pressures%2C+delivering+mobile+phases+that+don%E2%80%99t+evaporate.+%E2%88%86GMixing+occurs+when+EGP+absorbs+water+vapor%2C+causing+ionogel+shrinking+that+blue+shifts+the+diffraction.+Ammonia+sensors+incorporated+acrylic+acid+into+the+polymer.+Ammonia+absorbed+by+EGP+deprotonated+the+carboxyl+groups%2C+causing+swelling+that+red+shifts+the+diffraction.%0D%0AResponsive+pure+protein+organogels+were+fabricated+from+protein+hydrogels+by+exchanging+water+with+ethylene+glycol.+2DPC+albumin+organogels+swell+when+the+proteins+bind+ligands%2C+enabling+water+insoluble+analyte+detection+that+utilizes+protein+selectivity.+Organophosphorus+Hydrolase+organogels+catalyze+hydrolysis+of+organophosphate+nerve+agents+~160+times+faster+than+their+monomers+in+organic+solvent.%0D%0AOrganic+solvents+typically+denature+proteins.+Crosslinked+organogel+proteins+mostly+retain+their+native+protein+reactivity+because+the+proteins+are+immobilized%E2%80%94i.e.+stabilized%E2%80%94during+hydrogel+polymerization.+Protein+polymer+phase+separation+that+accompanies+the+solvent+exchange+irreversibly+changes+the+polymer+morphology%2C+however+the+proteins+retain+their+secondary+structure+and+solvation+shell+waters+in+pure+ethylene+glycol.&rft.date=2020-01-16&rft.type=University+of+Pittsburgh+ETD&rft.type=PeerReviewed&rft.format=application%2Fpdf&rft.language=en&rft.identifier=http%3A%2F%2Fd-scholarship-dev.library.pitt.edu%2F37618%2F7%2FNatasha%2520Smith%2520Final%2520ETD.pdf&rft.identifier=++Smith%2C+Natasha++(2020)+Development+of+2-Dimensional+Photonic+Crystal+Sensors+and+Pure+Protein+Organogel+Sensing+and+Biocatalytic+Materials.++Doctoral+Dissertation%2C+University+of+Pittsburgh.++++(Unpublished)++