Fig. 2.

Experimental platform stretching quantification. (a) Pencil shavings were scattered throughout the membranes and were put under 2.5% and 5% strain with 0% being the resting condition. Engineering strain (= stretch ratio – 1) along the axis of the stretching device (x/horizontal direction) was quantified by tracking fiduciary markers before and after 2.5% (b), and 5% (c) strains, measuring the resulting displacements, and calculating strains accordingly. Each strain condition was repeated three times, and, in all cases, the resulting strain fields showed little to no spatial variation across x/horizontal and y/vertical positions. As expected, transverse strains (y/vertical direction) and shear strains were very small relative to axial strains (data not shown)