Shape memory polymer resonators as highly sensitive uncooled infrared detectors

Abstract

Uncooled infrared detectors have enabled the rapid growth of thermal imaging applications. These detectors are predominantly bolometers, reading out a pixel’s temperature change due to infrared radiation as a resistance change. Another uncooled sensing method is to transduce the infrared radiation into the frequency shift of a mechanical resonator. We present here highly sensitive resonant infrared sensors, based on thermo-responsive shape memory polymers. By exploiting the phase-change polymer as transduction mechanism, our approach provides 2 orders of magnitude improvement of the temperature coefficient of frequency. Noise equivalent temperature difference of 22 mK in vacuum and 112 mK in air are obtained using f/2 optics. The noise equivalent temperature difference is further improved to 6 mK in vacuum by using high-Q silicon nitride membranes as substrates for the shape memory polymers. This high performance in air eliminates the need for vacuum packaging, paving a path towards flexible non-hermetically sealed infrared sensors.

Intrinsic carbon nanotube liquid crystalline elastomer photoactuators for high-definition biomechanics

“…Intelligent devices integrated with smart materials which can convert environmental stimuli ( e.g. , heat, 1,2 light, 3 electric fields, 4 magnetic fields, 5 and moisture 6 ) into shape deformations or mechanical motions have attracted widespread attention in the fields of motors, 7 sensors, 8–11 soft robots 12 and artificial muscles. 13 Among these various types of actuating schemes, light-driven strategies based on photothermal effects are most fascinating because they can be manipulated using a variety of light sources to enable localized actuation, remote control, etc.…”

A Review of Shape Memory Polymers and Composites: Mechanisms, Materials, and Applications

“…[ 183 ] The resulting flexible light‐emitting device could be stretched up to 45% linear strain without losing the electroluminescent properties. Adiyan and co‐workers [ 184 ] introduced the transduction property of the SMPs into the uncooled IR sensor. A phase transition behavior was connected with IR absorbing, and resonators based on SMPs successfully developed.…”

Moisture-induced autonomous surface potential oscillations for energy harvesting

“…On the other hand, forced oscillation is a phenomenon that various and repeated actions can be induced by frequently changed external stimulations, such as forces, temperature, light, or alternating electricity (AC) inputs, etc. [24][25][26][27][28] Autonomous oscillations or "self-oscillating" behaviors are continuously changing activities that don't require repeated switching by the external stimulations. [29][30][31][32][33] In nature, autonomous oscillations widely exist in living organisms, such as heartbeats, brain waves, and biochemical reactions 31 .…”