Acoustic monitoring of the gelation of a colloidal suspension

TL;DR

This paper demonstrates that acoustic spectral analysis can effectively monitor gelation in silica suspensions, providing a simple, in-situ alternative to traditional rheological methods for industrial applications.

Contribution

It introduces an empirical acoustic approach to track gelation, linking acoustic measurements with rheological gelation time in silica suspensions.

Findings

Acoustic gelation time correlates with rheological gelation time.

Spectral acoustic measurements can monitor gelation in opaque systems.

Method enables in-situ, real-time monitoring in industrial settings.

Abstract

Because they are sensitive to mechanical properties of materials and can propagate even in opaque systems, acoustic waves provides us with a powerful characterization tool in numerous fields. Common techniques mostly rely on time-of-flight measurements and do not exploit the spectral content: however, sound speed and attenuation spectra contain rich information. Such an acoustic spectroscopy already exists and allows to retrieve subtle information on systems of well-known physico-chemistry, but modeling becomes out of reach for industrial systems. In this article, we use a simple empirical approach to monitor the gelation of silica suspensions: we show that the gelation time obtained from acoustic measurements is proportional to this determined with more conventional rheological characterization. Such a results thus opens the way for in-situ monitoring of time-evolving systems in industrial context with acoustic methods only.