BEGIN:VCALENDAR VERSION:2.0 CALSCALE:GREGORIAN PRODID:iCalendar-Ruby BEGIN:VEVENT CATEGORIES:Lectures & Presentations DESCRIPTION:NQPI Seminar | Polymer-solvent interaction and molecular reorie ntation: Implication to solvent-assisted deformation at the polymer surface using AFM and SFG spectroscopy\, Oct. 20\n\nThe Nanoscale and Quantum Phen omena Institute (NQPI) 's Seminar Forum series features Tharushi Ambagaspit iya discussing "Polymer-solvent interaction and molecular reorientation: Im plication to solvent-assisted deformation at the polymer surface using AFM and SFG spectroscopy" Oct. 20 at 4:10 p.m. in Walter 245.\n\n \n\nAmbagaspi tiya is a graduate student in Chemistry & Biochemistry at Ohio University.\ n\n \n\nAbstract: Methacrylate based polymers are widely used in various in dustries. In many applications\, polymers often get exposed to different li quid environments leading to the possibility of polymer dissolution. When e xposed to solvents\, polymers undergo structural deformation and molecular reorientation. This affects the usability and durability of polymers. In th is work\, two polymer thin films of poly(2-methoxy ethyl methacrylate) (pol yMEMA) and poly (2-tertbutoxy ethyl methacrylate) were exposed to two solve nts\; D2O and CDCl3 simultaneously. Polymer thin films were prepared by spi n coating 1% polymer solution in chloroform on quartz windows followed by a nnealing. Changes at the polymer – solvent interface were studied using sum frequency generation (SFG) spectroscopy and atomic force microscopy (AFM). SFG spectroscopy is a surface specific\, non-linear optical technique whic h yields vibrational spectra of molecules at interfaces. By using this tech nique\, the interfacial molecular organization of polymers before\, during\ , and after exposure to solvent molecules was studied. AFM imaging was used to compare microscopic surface changes at polymer – solvent interface befo re\, during\, and after exposure to solvent molecules. Appropriate closed f luid cells were used in both techniques to ensure effective solvent exposur e. Methoxy group (-OCH3) of polyMEMA shows the symmetric stretch vibration at ~2810 cm-1. The changes in the relative intensity of the peak on fitted spectra showed the polyMEMA surface undergoes molecular reorganization when exposed to D2O and CDCl3. Orientational analysis showed the -OCH3 group po sitions itself closer to the surface normal at the polymer-liquid interface under D2O. However\, -OCH3 group points away from the surface normal when polyMEMA is exposed to less polar CDCl3. AFM images and force measurements showed swelling and softening of polyMEMA surface while exposed to D2O. Upo n removal of D2O\, the swelled areas were imprinted on the surface as crate rs showing that the amorphous glassy structure of the polymer was disrupted due to solvent exposure. Dissolution of the polymer when exposed to CDCl3 was also evident from AFM studies. DTEND:20221020T211000Z DTSTAMP:20240921T064921Z DTSTART:20221020T201000Z GEO:39.322732;-82.10287 LOCATION:Walter Hall\, 245 SEQUENCE:0 SUMMARY:NQPI Seminar | Polymer-solvent interaction and molecular reorientat ion: Implication to solvent-assisted deformation at the polymer surface usi ng AFM and SFG spectroscopy\, Oct. 20 UID:tag:localist.com\,2008:EventInstance_41154860844497 URL:https://calendar.ohio.edu/event/nqpi_seminar_oct_20 END:VEVENT END:VCALENDAR