ISSN:
1435-1536
Keywords:
Key words Poly(N-isopropylacrylamide)
;
Poly(acrylic acid)
;
Cloud point
;
Thermoresponsive polymer
;
High pressure
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract We studied the effects of pH on the pressure–temperature dependence of coil–collapse transition for aqueous solutions of copolymers of N-isopropylacrylamide and acrylic acid (Ac). At low pressures, the transition temperature (T tr) increased with pressure, but T tr decrease with increasing pressure at pressures higher than 50–100 MPa. By increasing the pH, the transition contour shifted to a higher temperature. When the Ac content was increased, the effects of pH became more evident. From a calorimetric study at atmospheric pressure, ΔH tr was found to become smaller by increasing the portion of the ionized residues in the copolymer. The ratio to the van't Hoff enthalpy changes became larger with an increase in pH, which indicated that the production of charge decreased the cooperative domain size.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s003969900231
Permalink
