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PRESSURE AND TEMPERATURE RESPONSE OF A STIMULI-RESPONSIVE POLYMER PROBED WITH RAMAN MICROSCOPY

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Date Issued:
2014
Abstract/Description:
Poly(N-isopropylacrylamide) (PNIPAM) is a thermo-responsive hydrogel; that is, it is a macromolecule which exists in a hydrated state beneath its lower critical solution temperature (LCST). Polymers such as PNIPAM undergo a phase transition in response to changes in temperature, pressure, pH, salt concentration, and the addition of co-solvents. Previously, visible-light microscopic measurements of the pressure-induced phase transition have been hindered by the lack of a pressurization apparatus with the short working distance and optical transmission properties necessary for high resolution microscopy. We employ a high pressure setup which uses a fused silica micro-capillary to contain the sample. Our experiment reveals differences in the spatial evolution of the phase change across the temperature and pressure thresholds, and Raman measurements allude to conformational differences in the evolution of the phase transitions. The Raman peaks positions are in agreement with previous FTIR measurements, and due to a difference in selection rules additional vibrational bands are observed in the Raman spectra.
Title: PRESSURE AND TEMPERATURE RESPONSE OF A STIMULI-RESPONSIVE POLYMER PROBED WITH RAMAN MICROSCOPY.
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Name(s): Cariker, Coleman, Author
Schulte, Alfons, Committee Chair
University of Central Florida, Degree Grantor
Type of Resource: text
Date Issued: 2014
Publisher: University of Central Florida
Language(s): English
Abstract/Description: Poly(N-isopropylacrylamide) (PNIPAM) is a thermo-responsive hydrogel; that is, it is a macromolecule which exists in a hydrated state beneath its lower critical solution temperature (LCST). Polymers such as PNIPAM undergo a phase transition in response to changes in temperature, pressure, pH, salt concentration, and the addition of co-solvents. Previously, visible-light microscopic measurements of the pressure-induced phase transition have been hindered by the lack of a pressurization apparatus with the short working distance and optical transmission properties necessary for high resolution microscopy. We employ a high pressure setup which uses a fused silica micro-capillary to contain the sample. Our experiment reveals differences in the spatial evolution of the phase change across the temperature and pressure thresholds, and Raman measurements allude to conformational differences in the evolution of the phase transitions. The Raman peaks positions are in agreement with previous FTIR measurements, and due to a difference in selection rules additional vibrational bands are observed in the Raman spectra.
Identifier: CFH0004694 (IID), ucf:45246 (fedora)
Note(s): 2014-12-01
B.S.
Sciences, Dept. of Physics
Bachelors
This record was generated from author submitted information.
Subject(s): polymer
Raman
spectroscopy
PNIPAM
Persistent Link to This Record: http://purl.flvc.org/ucf/fd/CFH0004694
Restrictions on Access: public
Host Institution: UCF

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