Large-strain and full-color change photonic crystal films used as mechanochromic strain sensors

Abstract

Mechanochromic strain sensors based on photonic crystals, which can change structural color upon mechanical deformation, are promising for many applications including health monitoring and damage detection. Here, a large-strain and full-color change photonic crystal film as a mechanochromic strain sensor is reported. The mechanochromic photonic crystal (MPC) film with grating nanostructure is achieved by a fast and low-cost inverted nanoimprint lithography. The film enables bright and reversible color shift in the full visible range as it is stretched up to a large strain, which is proven in strain direction parallel and perpendicular to the grating. It is demonstrated that the MPC film can be used as a mechanochromic strain sensor able to visualize strain evolution and strain range of low carbon steel in tensile test, which brings a significant step toward visualizing strain monitoring.

Soft Optomechanical Systems for Sensing, Modulation, and Actuation

“…Nanoimprint lithography (NIL) offers an easy, low‐cost methodology to produce large area diffraction gratings, [ 56,57 ] and its use for mechanochromic sensing have been reported by several authors. For example, colorimetric pressure sensors were proposed, [ 58–60 ] which could be applied in non‐contact intraocular pressure sensing. [ 59 ] Diffraction gratings have also been exploited as self‐sensing mechanism to quantify the mechanical actuation in soft‐robotic structures, driven by pneumatic pressure [ 61 ] or temperature (by using shape memory alloy wires).…”

Lasing Emission from Soft Photonic Crystals for Pressure and Position Sensing

“…This facilitates the realization of a wide range of tunable functional devices suitable for various applications [14][15][16][17][18]. Concurrently, such alterations in optical wavelengths, presented as optical spectra [19][20][21][22] or visible color changes [23][24][25][26][27][28][29][30][31][32][33][34][35], are commonly employed for sensing or quantifying different types of stresses applied to this architecture. In recent years, there have been numerous reports on PhCs or metallic nanostructures with plasmonic resonance embedded in soft materials, designed for sensing various strain-related parameters such as physiological parameters [13,26,27], motions [28,29], uniform pressure [30][31][32], and different types of stress [20][21][22][33][34][35].…”

“…Concurrently, such alterations in optical wavelengths, presented as optical spectra [19][20][21][22] or visible color changes [23][24][25][26][27][28][29][30][31][32][33][34][35], are commonly employed for sensing or quantifying different types of stresses applied to this architecture. In recent years, there have been numerous reports on PhCs or metallic nanostructures with plasmonic resonance embedded in soft materials, designed for sensing various strain-related parameters such as physiological parameters [13,26,27], motions [28,29], uniform pressure [30][31][32], and different types of stress [20][21][22][33][34][35]. Most of these reports have demonstrated sensing via colorimetric changes in broad-band optical modes within large-area meta-structures [23][24][25][26][27][28][29][30][31][32][33][34][35].…”

“…In recent years, there have been numerous reports on PhCs or metallic nanostructures with plasmonic resonance embedded in soft materials, designed for sensing various strain-related parameters such as physiological parameters [13,26,27], motions [28,29], uniform pressure [30][31][32], and different types of stress [20][21][22][33][34][35]. Most of these reports have demonstrated sensing via colorimetric changes in broad-band optical modes within large-area meta-structures [23][24][25][26][27][28][29][30][31][32][33][34][35]. In comparison, only a few have explored sensing via spectral variations in narrow-band optical modes within localized meta-structures [19][20][21][22].…”