New techniques in sol–gel characterisation – mechanical measurements and fractal characteristics

Williams, P.Rhodri; Williams, Rhodri Ll.; Jones, Richard; Al-Hussany, Ala; Ravji, Sejal

Abstract

We report theoretical and experimental work which demonstrates how the viscoelastic dispersion of shear waves may be exploited in studies of the rheological properties of systems such as `critical-gels' – systems at the gel point. At the gel point a material undergoing gelation changes, from one in which only short range connectivity is present, to one in which structural self-similarity is sample-spanning. Experiments are described in which marked changes in high-frequency shear-wave dispersion are recorded during the viscoelastic-liquid to viscoelastic solid transition about the gel point. The results accord with theoretical treatments of the sol–gel transition, based on a modified form of the Gross–Marvin network model. We report how this modified model has been used to investigate the interdependence of the high- and low-frequency features of the evolving relaxation time spectra associated with the growth of discrete, mechanically self-similar nodal networks. An analysis of the growth of the networks reveals a scale-invariant characteristic of the underlying gel microstructure and an associated fractal dimension, df, in the range 1

Citation

Williams, P., Williams, R. L., Jones, R., Al-Hussany, A., & Ravji, S. (2000, August). New techniques in sol–gel characterisation – mechanical measurements and fractal characteristics. Presented at 8th International Conference on Non-Crystalline Materials, Aberystwyth, UK

• Presentation Conference Type: Conference Paper (published)
• Conference Name: 8th International Conference on Non-Crystalline Materials
• Start Date: Aug 6, 2000
• End Date: Aug 11, 2000
• Online Publication Date: Oct 18, 2001
• Publication Date: 2001
• Deposit Date: Jul 26, 2016
• Journal: Journal of Non-Crystalline Solids
• Print ISSN: 0022-3093
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 293-295
• Pages: 731-745
• DOI: https://doi.org/10.1016/S0022-3093%2801%2900852-3
• Keywords: M120, S440, S430, S310, R177
• Public URL: http://researchrepository.napier.ac.uk/Output/315525
• Additional Information: Special issue 8th Int. Conf. on Non-Crystalline Materials