Jump to main content
Jump to site search

Issue 3, 2011
Previous Article Next Article

Characterization of temperature-induced association in aqueous solutions of charged ABCBA-type pentablock tercopolymers

Author affiliations

Abstract

In this work, two novel linear ABCBA pentablock tercopolymers, which are composed of an anionic poly(4-styrenesulfonic acid sodium) (PSSS) block on both ends and two thermosensitive poly(N-isopropylacrylamide) (PNIPAAM) blocks that are separated by a hydrophilic poly(ethylene glycol) (PEG) block have been synthesized via a simple “one-pot” ATRP procedure. The two studied samples have the following compositions: (P(SSS)12-b-P(NIPAAM)63-b-P(EG)34-b-P(NIPAAM)63-b-P(SSS)12 (C34) and P(SSS)14-b-P(NIPAAM)65-b-P(EG)77-b-P(NIPAAM)65-b-P(SSS)14 (C77). The main difference between the copolymers is the length of the hydrophilic block, which plays a crucial role for the physical properties of the copolymers in aqueous solution. A solution of the C34 sample becomes turbid at elevated temperatures and compact interchain complexes are formed with a behavior that is reminiscent of a suspension of particles. A solution of C77 becomes turbid at intermediate temperatures but it is transformed to a transparent solution at high temperatures. Depending on the polymer concentration, this pentablock copolymer forms a fragmented or interconnected network at elevated temperatures. At sufficiently high polymer concentration, the viscosity measurements indicate that a reversible hydrogel is formed. The interchain complexes or networks are readily broken up under the influence of shear flow. The results from the small angle neutron scattering experiments reveal significant structural differences between the pentablock copolymers at different temperatures.

Graphical abstract: Characterization of temperature-induced association in aqueous solutions of charged ABCBA-type pentablock tercopolymers

Back to tab navigation

Publication details

The article was received on 30 Aug 2010, accepted on 16 Nov 2010 and first published on 10 Dec 2010


Article type: Paper
DOI: 10.1039/C0SM00892C
Soft Matter, 2011,7, 1168-1175

  •   Request permissions

    Characterization of temperature-induced association in aqueous solutions of charged ABCBA-type pentablock tercopolymers

    N. Beheshti, K. Zhu, A. Kjøniksen, K. D. Knudsen and B. Nyström, Soft Matter, 2011, 7, 1168
    DOI: 10.1039/C0SM00892C

Search articles by author

Spotlight

Advertisements