Fig. 6: Mechanism of lubrication performance of plant protein microgels in hard-soft contact surfaces.

Tribological performance of steel ball on PDMS contact surfaces showing (a) theoretical modelling of lubrication performance at a load of 2 N of exemplar plant protein microgels (pea, potato and mixed pea and potato microgel) showing close resemblance to the emulsions as opposed to the large friction coefficients obtained in presence of the native protein. Here the dashed lines show the best theoretical fit using Eq. 11 and (b) load dependency of microgels as compared to the native protein (matched protein content for Φ = 70 vol%) with 20:80 O/W emulsion as control with (c) schematic illustration of microgel performance as compared to native protein in hard-soft contacts. Friction coefficient (µ) is plotted as a function of entrainment speed (U). Results are plotted as average of three repeat measurements on triplicate measurements (n = 3 × 3) with error bars representing standard deviations.