Issue 35, 2015

Understanding the UCST-type transition of P(AAm-co-AN) in H2O and D2O: dramatic effects of solvent isotopes

Abstract

The UCST-type transition of poly(acrylamide-co-acrylonitrile) (P(AAm-co-AN)) (molar fraction of AN: 13.3%; PDI = 3.2) in H2O and D2O is explored and compared by applying turbidity, DLS as well as FTIR measurements. The transition temperature of P(AAm-co-AN) in D2O is observed to be almost 10 °C higher than that in H2O at the same concentration, demonstrating a dramatic solvent isotope effect. Such a phenomenon could be rooted from a stronger interaction among polymer chains in D2O than in H2O, as indicated from DLS results. It is also observed in second-derivative analysis of FTIR spectra in the ν(C[double bond, length as m-dash]O) region, where all C[double bond, length as m-dash]O groups participate in the formation of inter-/intra-chain hydrogen bonds (C[double bond, length as m-dash]O⋯H–N) in D2O while there is still part of relatively “free” C[double bond, length as m-dash]O groups in H2O. Moreover, we find in the temperature-dependent FTIR spectra that C[triple bond, length as m-dash]N groups exhibit hydrating behavior while C[double bond, length as m-dash]O groups present increased inter-/intra-molecular hydrogen bonding interaction (C[double bond, length as m-dash]O⋯H–N) upon cooling, revealing the later process to be the driving force of the UCST-type transition.

Graphical abstract: Understanding the UCST-type transition of P(AAm-co-AN) in H2O and D2O: dramatic effects of solvent isotopes

Supplementary files

Article information

Article type
Paper
Submitted
15 Jul 2015
Accepted
28 Jul 2015
First published
28 Jul 2015

Soft Matter, 2015,11, 7059-7065

Understanding the UCST-type transition of P(AAm-co-AN) in H2O and D2O: dramatic effects of solvent isotopes

L. Hou and P. Wu, Soft Matter, 2015, 11, 7059 DOI: 10.1039/C5SM01745A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements