Jump to main content
Jump to site search

Issue 24, 1996
Previous Article Next Article

Colloidal copolymer microgels of N-isopropylacrylamide and acrylic acid: pH, ionic strength and temperature effects

Abstract

Aqueous colloidal microgels have been prepared, based on poly(N-isopropylacrylamide)[poly(NIPAM)], cross-linked with bisacrylamide, containing 5% w/w acrylic acid (AAc) as a comonomer. Transmission electron micrographs of the microgels show that the copolymer microgels are monodisperse spheres. The size of the microgel particles containing 5% AAc has been studied, using dynamic light scattering, as a function of pH (3–10), ionic strength (10–4–10–1M NaCl) and temperature (20–75 °C). The hydrodynamic diameter of the copolymer microgels decrease both with increasing ionic strength (at pH 6 and 25 °C) and reversibly with increasing temperature at pH values of 2.6, 3.4 and 6.5. However, under isothermal conditions in 10–3M NaCl at 25 °C, the hydrodynamic diameter increases in going from pH 3.3–9.4. In addition, the temperature-induced conformational changes in the polymer chains have been followed using high-sensitivity differential scanning calorimetry (HSDSC). A comparison is made with the behaviour of poly(NIPAM) microgel particles, not containing AAc. Explanations are offered to account for the pronounced difference in the physico-chemical properties observed.

Back to tab navigation

Article information


J. Chem. Soc., Faraday Trans., 1996,92, 5013-5016
Article type
Paper

Colloidal copolymer microgels of N-isopropylacrylamide and acrylic acid: pH, ionic strength and temperature effects

M. J. Snowden, B. Z. Chowdhry, B. Vincent and G. E. Morris, J. Chem. Soc., Faraday Trans., 1996, 92, 5013 DOI: 10.1039/FT9969205013

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.


Search articles by author

Spotlight

Advertisements