Abstract
The effect of sodium chloride upon the thermally induced transitions in aqueous solutions, of poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (PEO−PPO−PEO) copolymers, has been investigated using high-sensitivity differential scanning calorimetry (HSDSC). The addition of salt to these systems lowers the onset temperature of micellization (critical micellization temperatureCMT). Moreover the accompanying decrease in phase separation temperature (cloud point) has provided an opportunity to investigate the calorimetric details of phase separation. The temperature region over which micellization occurs, in agreement with previously reported findings, is broad and indicates that micelles and unimers coexist over an extended temperature range. The cloud point on the other hand is characterized, calorimetrically, by a narrow and at times complex peak, indicating that the cooperativity of the transition is very high. For some systems, most notably P235 (EO27−PO39−EO27), a third transit...
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.