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The Effect of NaCl on the Conformational Behavior of Acenaphthylene Labeled Poly( N , N ‐diethylacrylamide) in Dilute Aqueous Solution
Author(s) -
Chen Yong,
Liu Mingzhu,
Bian Fengling,
Wang Bing,
Chen Shilan,
Jin Shuping
Publication year - 2006
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200500416
Subject(s) - aqueous solution , acenaphthylene , chemistry , fluorescence , fluorescence anisotropy , fluorescence spectroscopy , crystallography , anisotropy , organic chemistry , pyrene , biochemistry , physics , quantum mechanics , membrane
Abstract Summary: The effect of salts on the conformational behavior of acenaphthylene labeled poly( N , N ‐diethylacrylamide) (PDEA/ACE) has been investigated in dilute aqueous solution using UV‐vis and fluorescence spectroscopy. It is demonstrated here that the effectiveness of various salts in changing the lower critical solution temperature ( T LCS ) of the PDEA/ACE solution followed the Hoffmeister series. The addition of NaCl linearly lowered the T LCS . In dilute aqueous solution, the PDEA/ACE adopted a loose coil conformation below its T LCS . The PDEA/ACE adopted a compact globule conformation above the temperature at which the coil to globule transition (CGT) was completed. A fluorescence anisotropy investigation suggested that a molten globule conformation existed during the CGT of the PDEA/ACE solution. In all of the above three conformations, the PDEA/ACE was more compact in the presence of NaCl than in the absence of any salt.Temperature and NaCl concentration dependence of fluorescence anisotropy of a PDEA/ACE solution. Inset: thermodynamically stable states of PDEA/ACE.