A neglected mechanism for pressure-responsive color change is demonstrated using cellulose acetate composites prepared by direct (solvent) immersion annealing (DIA), with different loadings of activated charcoal filler. Namely, compressive plastic deformation of the translucent cellulose acetate leads to a decrease in the optical path length and a concomitant increase in the visibility of the opaque contrasting filler. Composites bearing 1-7 wt% activated charcoal exhibited a linear relationship between applied pressure and resulting pressure mark brightness in the range of 12-56 MPa.
View Article and Find Full Text PDF