In-situ visualisation of the micro-structure of a Carbopol gel during a confined microscopic flow

An in-situ visualisation of the microstructure of a Carbopol gel flowing in a micro-channel is presented. By means of a novel chemical protocol able to stain the solid material units of the gel with a fluorescent molecule we are able to accurately identify the solid/fluid material units advected by the confined microscopic flow. Based on this novel visualisation technique a full statistical description of the distributions of solid–fluid material units in the flow in terms of space and time averages, probability density functions and space–time correlations is reported for the first time. •A novel fluorescent labeling protocol of the Carbopol microstructure is developed.•A full description of the statistics of solid/fluid material elements is provided.•The size distribution of solid material elements follows the Weibull distribution.•The confinement leads to the emergence of secondary flows and time dependent flow fields.