Please use this identifier to cite or link to this item:
http://hdl.handle.net/11375/21426
Title: | Synthesis and Thermal Response of Poly(N-Isopropylacrylamide) Prepare By Atom Transfer Radical Polymerization |
Authors: | Xia, Yan |
Advisor: | Stöver, Harald D. H. |
Department: | Chemistry |
Keywords: | synthesis, thermal response, atom transfer, radical polymerization, PNIPAM, narrow-disperse, phase transition |
Publication Date: | Aug-2005 |
Abstract: | <p> Poly(N-isopropylacrylamide) (PNIPAM) has attracted much attention as a thermo-responsive polymer. However, the molecular weight (MW) dependence of its phase transition temperature is still controversial. This situation is largely due to the difficulty in synthesizing narrow-disperse PNIPAM. We have addressed the challenge and developed an atom transfer radical polymerization (ATRP) method to prepare narrow-disperse PNIPAM with moderate to high conversions, using branched alcohols as solvents. Aqueous solutions of these narrow-disperse PNIPAMs showed a dramatic decrease of the phase transition temperature with increasing molecular weight, as measured by turbidimetry and differential scanning calorimetry. Four other series of narrow-disperse PNIPAM with well-controlled molecular weights and with end groups of varying hydrophobicity were also synthesized by ATRP using the corresponding initiators, which enabled us to resolve the MW and end group effects. All the four series of samples showed an inverse molecular weight (MW) dependence of their phase transition temperature. The magnitude of the MW dependence decreased when using more hydrophobic end groups. The end groups were observed to have effects on the cloud point temperature, on the shape of the cloud point curves, and on the enthalpy of the phase transition.</p> |
URI: | http://hdl.handle.net/11375/21426 |
Appears in Collections: | Digitized Open Access Dissertations and Theses |
Files in This Item:
File | Description | Size | Format | |
---|---|---|---|---|
Xia_Yan_2005Aug_Masters..pdf | 5.35 MB | Adobe PDF | View/Open |
Items in MacSphere are protected by copyright, with all rights reserved, unless otherwise indicated.