A bio-inspired functional film embedded with fluorescent elastic microspheres for pressure sensing

Developments in global pressure and shear sensors are invaluable for flow visualization and force measurement and are indispensable tools for research in fluid mechanics. Here, we introduce a bio-inspired pressure-sensitive film that has high spatial resolution and a wide measurement range. The film is embedded with fluorescent elastic microspheres that emit light under appropriate excitation. These microspheres can be compressed under external pressure, and they fully recover as pressure is released. This pressure-induced deformation causes variations in microsphere emission intensity, establishing a quantitative relationship between pressure and emission intensity. Furthermore, this film has the potential for shear-force sensing via the use of digital image correlation to measure the displacements of microspheres under shear force. This functional film has an impressively broad scope of sensing applications, such as in air-flows, underwater, and in tactile-based settings.