Fig. 1
From: Chemically modified graphene films with tunable negative Poisson’s ratios
Tensile tests of chemically modified graphene films monitored by fluorescent digital image correlation. a Schematic diagram of the fluorescent digital image correlation (FDIC) measurement, where camera and lens detect light emitted from red fluorescent particles deposited onto the e-GO0 films (prepared by evaporation of GO solution synthesized at 0 °C). The emission filter allows only light from the excited fluorescent particles to pass. b–e Optical images of e-GO0 films with fluorescent particles on its surface, and the displacement fields U (b) and V (c), and the strain fields measured in the transverse (d) and longitudinal (e) directions from FDIC analysis. Source data are provided as a Source Data file
