Quantitative analysis of the structural relaxation of silica-PEO shake gel by X-ray and light scattering

• Published in: Polymer testing 2021-12, Vol.104, p.107391, Article 107391
• Main Authors: Tian, Qiang, Sun, Jiayi, Henderson, Mark Julian, Huang, Xuegang, Li, Na, Courtois, Jérémie, Almásy, László
• Format: Article
• Language: English
• Subjects: DLS; Relaxation; SAXS; Shake gel
• ISSN: 0142-9418; 1873-2348
• DOI: 10.1016/j.polymertesting.2021.107391

Relaxation mechanisms of shake gels (particle-polymer systems) are not yet fully understood, mainly because of the lack of effective structural parameters to describe relaxation processes. Small-angle X-ray scattering and dynamic light scattering methods were employed to track the relaxation processes in a water-based shake gel system, composed of 20 wt % of 24.8 nm silica nanoparticles and 0.3 wt % of poly(ethylene oxide) (PEO1000k). The gelation of the studied silica-PEO dispersion was readily induced by quick manual shaking (∼3 cycles/s). Temporal structural evolution of the shake gel after manual agitation was inferred from the development of the modeled parameters. The quantitative structural parameters extracted from the scattering data, i.e. nearest neighbor distance of silica nanoparticles and floc size of gel network, showed that the shake gel network quickly relaxes during the first 10–20 min following the shake-induced gelation, and then slowly reaches a quiescent structure after 1 h. •Temporal structural evolution of the silica-PEO shake gel immediately after shaking was characterized by X-ray and light scattering.•The relaxation behavior was depicted by the quantitative relaxation parameters — nearest neighbor distance of silica particles and floc size of gel network.•The studied shake gel network quickly relaxed during the first 10–20 min but slowly thereafter.•This work advanced the deep understanding of fundamental relaxation processes of shake gels at nanometric resolution.