Issue 48, 2022

Structure formation of PNIPAM microgels in foams and foam films

Abstract

Responsive aqueous foams are very interesting from a fundamental point of view and for various applications like foam flooding or foam flotation. In this study thermoresponsive microgels (MGs) made from poly(N-isopropyl-acrylamide) (PNIPAM) with varying cross-linker content, are used as foam stabilisers. The foams obtained are thermoresponsive and can be destabilised by increasing the temperature. The structuring of MGs inside the foam films is investigated with small-angle neutron scattering and in a thin film pressure balance. The foam films are inhomogeneous and form a network-like structure, in which thin and MG depleted zones with a thickness of ca. 30 nm are interspersed in a continuous network of thick MG containing areas with a thickness of several 100 nm. The thickness of this continuous network is related to the elastic modulus of the individual MGs, which was determined by atomic force microscopy indentation experiments. Both, the elastic moduli and foam film thicknesses, indicate a correlation to the network elasticity of the MGs predicted by the affine network model.

Graphical abstract: Structure formation of PNIPAM microgels in foams and foam films

Associated articles

Supplementary files

Article information

Article type
Paper
Submitted
29 Jul 2022
Accepted
18 Oct 2022
First published
19 Oct 2022
This article is Open Access
Creative Commons BY license

Soft Matter, 2022,18, 9249-9262

Structure formation of PNIPAM microgels in foams and foam films

M. Kühnhammer, K. Gräff, E. Loran, O. Soltwedel, O. Löhmann, H. Frielinghaus and R. von Klitzing, Soft Matter, 2022, 18, 9249 DOI: 10.1039/D2SM01021F

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements