Thermal Actuator Research Articles

A dual-drive mode MEMS device for in-situ static/dynamic electro-mechanical characterization of nanomaterials

A novel dual-drive MEMS device integrated with both a thermal actuator and an electrostatic actuator is proposed and fabricated, which realizes the convenient in-situ electro-mechanical test for nanomaterials. The drive mode can be agilely selected to analyze different mechanical properties and the accuracy of the test can be verified by self-contrast of the two driving modes. Using the nanomanipulator as the transfer method, coupled mechanical and electrical tests are carried out for TiO2 nanowires. The measured Young's modulus of the nanowire in the two driving modes are 78.2 GPa and 85.6 GPa, and the fracture stress are 562 MPa and 584 MPa, respectively. The electron beam (e-beam) irradiation effect on electrical properties is investigated. Meanwhile, the resistance of the nanowires is determined as a variable of strain, which demonstrates the changes in resistance are the result of the loaded strains. The resistance decreases slightly after 2000 cycles of tensile, which is believed to be a delayed response brought about by electron beam irradiation. The experiment results indicate that the proposed MEMS device will facilitate the in-situ test of 1D/2D nanomaterials.

Analytical design and finite element analysis of a microgripper for characterizing a single microcapsule

The typical technique of hardness testing of pharmaceutical microcapsules uses pressure transducer-based bulky devices by averaging mechanism. This not only produces non-precise results but also causes wastage of costly core material present in the microcapsules. To overcome these issues a miniaturized version of the device using a micro electromechanical system (MEMS)-based microgripper has been proposed, which can mechanically characterize a single microcapsule of sizes ranging from 5 µm to 20 µm with a maximum rupture force of 13.33 mN. The proposed microgripper consists of a hybrid chevron thermal actuator and integrated capacitive force sensor and has been designed using standard silicon-on-insulator multi-user MEMS processes with a device size of 2.5 × 3.2 mm2. The microgripper is efficiently modelled to produce a temperature gradient of about 350 °C from the actuator to the jaws making it able to handle temperature-sensitive samples.

Cutaneous Microcirculatory Flow Sensing for Flap Monitoring in a Porcine Model of Arterial and Venous Occlusion

PURPOSE: Cutaneous devices employing near infrared spectroscopy (NIRS) for continuous free flap tissue oxygenation (StO2) monitoring have several limitations. Confounding factors like skin pigmentation and thickness, ambient light incursion, and inconsistency at the skin-sensor interface can alter StO2 measurements. As an alternative means for peripheral free flap monitoring, we present a novel probe that calculates microvascular blood flow velocity by measuring tissue thermal diffusion. This device is cutaneous, wireless and not subject to the same confounding variables as NIRS. METHOD: The cutaneous perfusion sensor includes 5 thermistors, a Bluetooth chip, and small battery mounted on circuit board. A thermal actuator (4-mm diameter) delivers a small amount of thermal power to the surface of the skin. The device is cutaneously mounted with a silicone acrylate adhesive onto target tissue. The diffusion of heat is measured and analytically converted into a measurement of microcirculatory blood flow velocity. Rapid thermal diffusion occurs in situations of high tissue perfusion, while slower thermal diffusion indicates slower or absent near-surface blood flow. This device was tested alongside Vioptix T.Ox in a porcine rectus abdominus myocutaneous flap model of arterial and venous pedicle occlusion. After flap elevation, the flow device and T.Ox were applied to the skin. Acland clamps were alternately applied to the flap artery and veins to achieve conditions of flap ischemia and congestion, each lasting 15 minutes, with a 15 minute intervening recovery period. In total, 10 devices were tested on 16 flaps in 10 separate pigs over 60 unique vaso-occlusive events. RESULTS: Continuous monitoring was accomplished and no connection loss was observed with either T.Ox or the novel devices. Flow measurements were responsive to both ischemia and congestion, and returned to baseline during recovery periods. Flow measurements corresponded with vascular occlusion and release, and closely followed StO2. Cross-correlation at zero lag showed agreement between these two sensing modalities, ranging from 0.76 to 0.83. Two novel devices tested simultaneously on the same flap showed only minor variations in flow measurements, with a cross-correlation of 0.87. CONCLUSION: This novel probe is capable of detecting changes in tissue microcirculatory blood flow. This device performed well in a swine model of flap ischemia and congestion, and shows promise as a potentially useful clinical tool. Because flow measurements are not affected by the variable lighting and light absorbing properties of tissue, this monitoring strategy has the potential to provide more consistent information than NIRS. Future studies will characterize longevity of the device over a period of several days.

Actuation performances of catkin fibers reinforced thiol-acrylate main-chain liquid crystalline elastomer

ABSTRACT Liquid crystalline elastomers (LCEs) have been utilized as an important class of smart actuator materials. However, the modest actuation mechanical and robustness performances remain a challenge. Inspired by the specific structures, well mechanical properties and physico-chemical characteristics of some natural plant fibers, a composite of thiol-acrylate main-chain LCE matrix incorporated with catkin fibers is designed and developed. The catkin fibers build a network as reinforcement phase, and demonstrate effective compatibility and integration property with the matrix, their high flexibility can be adapted to the large deformational performance of LCE matrix. The prepared LCE composite demonstrates strong mechanical actuation properties. The modulus and driving force triggered by the stimuli are obviously increased. The tensile strength and fatigue failure resistant property under high loadings and repeated cycles of thermal actuation or photothermal actuation are greatly enhanced. While the stimulus response deformation rate, phase transition temperature and liquid crystal phase structure of the LCE matrix, and so on, do not weaken or change. This work promotes the LCE materials’application potential and broadens the application value of natural plant fibers.

Performance comparison of coiled actuators made of PA6 single fiber and yarn

The application of twisted and coiled synthetic fibers for energy conversion is promising due to their flexibility, lightweight and wearability. Although there are significant efforts on improving the performance of twisted and coiled polymer fibers, new understanding is still required about possible effects of the fabrication parameters and the precursor fiber type on thermal actuation performance and energy conversion efficiency. Herein, two types of coiled actuators were fabricated by inserting certain numbers of twists to polyamide 6 (PA6) single fibers and yarns, and the effects of twisting numbers and precursors type on actuation responses, physical properties, and structural changes were investigated. It was demonstrated that fiber-based and yarn-based actuators had different actuation properties where the former one showed a greater actuation load and the latter one had a faster torsional actuation. Also, the yarn-based samples generated faster torsion actuations with the rotation speed up to 16,000 rpm/m, and presented higher thermal actuation sensitivity. Depending on the obtained characteristics, the prepared actuators were used in developing smart textiles for different applications such as fabricating small spring-like robot, smart curtains, and infrared-sensitive functional gloves. • The operating principle of the fiber actuator was discussed. • The actuation properties of coiled PA6 single fiber and yarn have been compared. • The impact of the twisting and coiling process on the internal arrangements of precursors is investigated. • The different applications in textile for twisted fiber-based actuator are realized.

Noninvasive platinum thin-film microheater/temperature sensor array for predicting and controlling flow boiling in microchannels

Thermal sensors and actuators are usually introduced at/in micro-channels in two ways: first, in an invasive manner through drilled holes which can lead to leakage problems and a change in channel dimensions and second, mounted in a non-invasive manner outside the channel which reduces heat transfer, accuracy, precision and response time. These problems are multiplied as soon as microchannel boiling with associated rapid thermal effects is investigated. Therefore, in this work, a platinum microheater/temperature sensor array has been developed to provide non-invasive, but nevertheless direct heating and temperature measurement at several locations along microchannels. This array comes without the mentioned disadvantages, resulting in ultra-fast response times that are limited only by the measurement speed of the sensor resistance and linear temperature coefficient of resistance. The working platinum area of each element in the array is only 238 nm thick, 0.1 mm wide and 0.5–2 mm long. The structures can be operated in heating and temperature measurement mode simultaneously. They are integrated into microreactors with the working surface as a side wall of a microchannel and in direct contact with the flowing fluid. Since the structures are deposited on transparent Pyrex glass in a cleanroom process, optical observation of two-phase flow boiling processes is possible for flow regime identification. The maximum operating temperature of the Pt microstructures is 450 °C and the linear temperature coefficient of resistance is about 2.98 × 10−3 °C−1. The relative measurement error of temperature measurements is less than 0.05% due to 2.9 µm thick highly conductive electroplated gold pads which form the electrical contact to the Pt microheaters/T-sensors. The platinum heater structures are capable of generating stationary vapor bubbles with a defined size proportional to the applied heating power. They can also predict two-phase flow boiling regimes (e.g. slug flow), vapor bubble length and frequency via the periodic signal of the measured temperature. Furthermore, they allow accurate calculation of heat transfer coefficients using the exact fluid temperatures measured with the Pt structures at the inlet and outlet of the microchannel, rather than analytically calculated values from temperature measurements outside the channel.

Thermal actuation shape memory of ultra-high-molecular-weight polyethylene (UHMWPE) with molecular orientation

• Preparation of shape memory UHMWPE/HDPE samples with molecular orientation. • Cyclic tensile shape memory property of UHMWPE/HDPE samples. • Movement and evolution of chain segments in shape-changing process. Conventional compression-molding method cannot illustrate the effect of molecular orientation on shape memory property. Herein, high-density polyethylene (HDPE) is incorporated into ultra-high-molecular-weight polyethylene (UHMWPE) to prepare samples with molecular orientation by the single screw extrusion and traction machine. Interestingly, the shape recovery rate (R r ) of samples with the same tensile direction as molecular orientation decreases from 66.13% to 60.71% with the traction rate, while the R r of samples with tensile direction perpendicular to molecular orientation exhibits an opposite tendency in cyclic tensile shape memory tests. Meanwhile, the shape fixation rate of these two samples does not change significantly. In addition, the possible mechanism of thermal actuation shape memory of samples with molecular orientation is interpreted.

Bio-inspired thermal responsible liquid crystal actuators showing shape and color variations simultaneously

BackgroundInspired by butterflies, a series of photonic polymers and butterfly-shaped LC actuators were fabricated using a laser cutter that show reversible curling and color variations simultaneously. MethodsTo fabricate a polymer film that shows thermal actuation and color variation simultaneously, cholesteric liquid crystal films consisting of planar and focal-conic alignment layers were designed and fabricated. Significant findingsPhotonic polymers were synthesized via a one-step polymerization, which simultaneously show color variation and thermal actuation. The planar-co-focal conic construction of the fabricated liquid crystal films was confirmed using SEM. Upon heating, the planar-co-focal-conic constructed film is observed to curl from the bottom to top direction due to the shrinkage of the top planar layer being higher than that of the bottom focal-conic layer. Both thermally induced reversible U-shaped curling and helical actuations for the as-synthesized planar-co-focal conic films were successfully achieved. Butterfly-shaped LC actuators were fabricated using a laser cutter showing reversible curling and color variations simultaneously. These predesigned liquid crystalline actuators with planar-co-focal-conic layers are expected to show great potential for soft robotics and optical devices.

Experimental Investigation of a Thermally Responsive Actuator Based on Metallic Molybdenum Disulfide: A Conceptual Analysis

Abstract Actuators that convert external stimuli to mechanical energy have aroused strong attention for emerging applications in robotics, artificial muscles, and other fields. However, their limited performance under harsh operating conditions evidenced by the low cycle life and hysteresis has restricted their practical applications. Here, a thermal-driven actuator based on layered metallic molybdenum disulfide (1T MoS2) nanosheets is demonstrated. The active actuator film exhibits fully reversible and highly stable (>99.296% in 2700 cycles) thermal-mechanical conversion over a wide temperature window (from −60 °C to 80 °C). Importantly, 1T MoS2 film shows a fast response with the bending rate and the recovery rate of >1.090 rad s−1 and >0.978 rad s−1, respectively. The assembled actuator can lift 20 times its weight over several centimeters for more than 200 cycles. This work, for the first time, demonstrates the thermoresponsive characteristics of 1T MoS2 in developing the thermal actuator, which may open new opportunities for various applications, such as robotics, artificial muscles, and human assist devices.

Production and performance of a low temperature shape-memory actuator based on twisted-coiled spring mechanics

Demand for new types of actuators continues to grow, and novel approaches have been made possible by the advent of new materials and fabrication strategies. Self-powered actuators have attracted significant attention owing to their ability to be driven by elements in ambient environments. This type of actuator can be used in flexible strain sensors, artificial muscles, soft robotics, and smart breathing textiles. However, petrochemical-based polymers are generally environmentally unfriendly and cause ecological problems. The use of biodegradable polymers is one of the preferred solutions to ecological problems. Polylactic acid is a biodegradable and biocompatible polymer with a high potential. In this study, nanoclay reinforced polylactic acid/thermoplastic polyurethane was used as a precursor. The yarn that was produced was highly twisted. The twisted yarn was then shaped into a coiled structure via mandrel annealing. An apparatus was designed to investigate the thermal actuation behavior of twisted-coiled yarn in an isometric state. The blocked force and free stroke were calculated in an isometric state by using linear material equations. The thermal actuation behavior of the twisted-coiled yarn was also studied in the isotonic state. This precursor exhibited a considerable two-way shape-memory effect in a twisted-coiled structure. It also showed a significant reversible contraction stroke within the low temperature range. The theoretical stroke was determined using two different models: the force–stroke equation and spring mechanics. The theoretical results were compared with the experimental results, which revealed acceptable agreement between the theoretical and experimental values.

Controlling transonic shock–boundary layer interactions over a natural laminar flow airfoil by vortical and thermal excitation

Investigations have been performed via implicit large eddy simulations to study the overall effects of exciting a flow field by thermal (wall-heating and wall-cooling) and vortical (with high and low frequencies) actuation. The actuator is placed on the suction surface of a natural laminar flow (SHM-1) airfoil having an angle of attack of α=0.38° (cruise setting). Oncoming flow has a Mach number of 0.72, and a Reynolds number based on a chord of Re=16.2×106, for which a complex shock system is formed on the suction surface. Vorticity dynamics of the flow is studied using time series of vorticity at different locations above the suction surface and instantaneous contour plots of vorticity in the domain. An inspection of the flow using snapshots of ∇ρ and ∇(ρT) is done to characterize the numerical schlieren. The comparative effects of the various forms of excitation on the shock–boundary layer interactions (SBLI) have been analyzed using time series of the magnitudes of ∇ρ across the identified shock structures from numerical schlieren snapshots. Also, the role of the frequency of imposed vortical actuation has been studied using vorticity and Mach contours for a comparative understanding of the control of the SBLI.

Optimal thermal actuation for mirror temperature control

The latest generation wafer scanners use extreme ultraviolet light to project a pattern of electronic connections onto a silicon wafer. A significant part of the projection light is absorbed by the mirrors in the projection system. This causes the mirrors to heat up and expand, which leads to a significant reduction in the imaging quality of the wafer scanner. The imaging quality can be improved by applying an additional actuation heat load to the mirrors. Because the wafer scanner can be used with a large number of different illumination settings (which lead to different load cases) and the number of thermal actuators is limited, designing an effective actuation heater layout is an important but nontrivial task. To assist this design process, this paper proposes a computational framework to optimize a small number of spatial actuation heat load shapes with their corresponding intensities for a large number of load cases. It is guaranteed that the obtained actuation heat load shapes can keep the steady-state temperature in the optical surface of the mirror sufficiently close to a desired temperature in all considered load cases. The proposed computational framework is applied to a representative three-dimensional finite element model of a mirror. The obtained actuation heat load shapes and their corresponding intensities provide insights for the design of a thermal actuation layout for mirror heating.

Computational Modeling of Deep Tissue Heating by an Automatic Thermal Massage Bed: Predicting the Effects on Circulation.

Automatic thermal and mechanical massage beds support self-managed treatment, including reduction of pain and stress, enhanced circulation, and improved mobility. As the devices become more sophisticated (increasing the degrees of freedom), it is essential to identify the settings that best target the desired tissue. To that end, we developed an MRI-derived model of the lower back and simulated the physiological effects of a commercial thermal-mechanical massage bed. Here we specifically estimated the tissue temperature and increased circulation under steady-state conditions for typical thermal actuator settings (i.e., 45–65°C). Energy transfer across nine tissues was simulated with finite element modeling (FEM) and the resulting heating was coupled to blood flow with an empirically-guided model of temperature-dependent circulation. Our findings indicate that thermal massage increases tissue temperature by 3–8°C and 1–3°C at depths of 2 and 3 cm, respectively. Importantly, due to the rapid (non-linear) increase of circulation with local temperature, this is expected to increase blood flow four-fold (4x) at depths occupied by deep tissue and muscle. These predictions are consistent with prior clinical observations of therapeutic benefits derived from spinal thermal massage.

Fast fluid heating by adaptive flow reorientation

Transport of scalar quantities such as e.g. heat or chemical species in laminar flows is key to many industrial activities and stirring of the fluid by flow reorientation is a common way to enhance this process. However, “How best to stir?” remains a major challenge. The present study aims to contribute to existing solutions by the development of a dedicated flow-control strategy for the fast heating of a cold fluid via a hot boundary in a representative case study. In-depth analysis of the dynamics of heating in fluid flows serves as foundation for the control strategy and exposes fluid deformation as the “thermal actuator” via which the flow affects the heat transfer. This link is non-trivial, though, in that fluid deformation may both enhance and diminish local heat exchange between fluid parcels and a fundamental “conflict” between local heat transfer and thermal homogenisation tends to restrict the beneficial impact of flow to short-lived episodes. Moreover, the impact of fluid deformation on the global fluid heating is primarily confined to the direct proximity of the moving boundary that drives the flow. These insights imply that incorporation of the thermal behaviour is essential for effective flow-based enhancement strategies and efficient fluid mixing, the conventional approach adopted in industry for this purpose, is potentially sub-optimal. The notion that global heating encompasses two concurrent processes, i.e. increasing energy content (“energising”) and thermal homogenisation, yields the relevant metrics for the global dynamics and thus enables formulation of the control problem as the minimisation of a dedicated cost function. This facilitates step-wise determination of the “best” flow reorientation from predicted future evolutions of actual intermediate states and thereby paves the way to (real-time) regulation of scalar transport by flow control in practical applications. Performance analyses reveal that this “adaptive flow reorientation” significantly accelerates the fluid heating throughout the considered parameter space and thus is superior over conventional periodic schemes (designed for efficient fluid mixing) both in terms of consistency and effectiveness. The controller in fact breaks with conventions by, first, never selecting these periodic schemes and, second, achieving the same superior performance for all flow conditions irrespective of whether said mixing occurs. The controller typically achieves this superiority by thermal plumes that extend from the hot wall into the cold(er) interior and are driven by two alternating and counter-rotating circulations.

Optimization of an amplification mechanism enabling large displacements in MEMS-based nanomaterial testing devices

In this paper we report on the optimization of an amplification mechanism to enable large displacements in microelectromechanical systems (MEMS). As a case study, we considered a MEMS-based platform for the mechanical testing of nanomaterials, but the results we obtained can be extended to other devices, too. The studied device consists of a couple of V-shaped thermal actuators, heat sink beams, comb drives for sensing the displacements delivered by the actuators to the sample to be tested, and an amplification stage capable of amplifying the produced displacements to tens of micrometers. Regarding the amplification stage, three different schemes were designed and simulated in order to identify the optimal solution. To this aim, static structural analyses have been carried out to predict the performance of the amplification mechanism with respect to geometrical parameters, such as inclination angle, length or width of the beams embedded in the amplification stage. An amplification factor as large as 50 is found. The numerical results show good agreement with those obtained from analytical models. The performance of the complete device is also evaluated through 3D steady-state static thermal-electrical analyses under variable voltage applied to the actuators. • Different types of amplification mechanisms have been analyzed in order to enable large displacements in MEMS devices. • The mechanism consisting of a V-shaped beam provided the best performance. • The final device was designed as able to deliver a displacement of ~1 μm to the sample, while not overcoming 81 °C.

Submillimeter-scale multimaterial terrestrial robots.

Robots with submillimeter dimensions are of interest for applications that range from tools for minimally invasive surgical procedures in clinical medicine to vehicles for manipulating cells/tissues in biology research. The limited classes of structures and materials that can be used in such robots, however, create challenges in achieving desired performance parameters and modes of operation. Here, we introduce approaches in manufacturing and actuation that address these constraints to enable untethered, terrestrial robots with complex, three-dimensional (3D) geometries and heterogeneous material construction. The manufacturing procedure exploits controlled mechanical buckling to create 3D multimaterial structures in layouts that range from arrays of filaments and origami constructs to biomimetic configurations and others. A balance of forces associated with a one-way shape memory alloy and the elastic resilience of an encapsulating shell provides the basis for reversible deformations of these structures. Modes of locomotion and manipulation span from bending, twisting, and expansion upon global heating to linear/curvilinear crawling, walking, turning, and jumping upon laser-induced local thermal actuation. Photonic structures such as retroreflectors and colorimetric sensing materials support simple forms of wireless monitoring and localization. These collective advances in materials, manufacturing, actuation, and sensing add to a growing body of capabilities in this emerging field of technology.

Exceptionally high work density of a ferroelectric dynamic organic crystal around room temperature

Dynamic organic crystals are rapidly gaining traction as a new class of smart materials for energy conversion, however, they are only capable of very small strokes (<12%) and most of them operate through energetically cost-prohibitive processes at high temperatures. We report on the exceptional performance of an organic actuating material with exceedingly large stroke that can reversibly convert energy into work around room temperature. When transitioning at 295–305 K on heating and at 265–275 K on cooling the ferroelectric crystals of guanidinium nitrate exert a linear stroke of 51%, the highest value observed with a reversible operation of an organic single crystal actuator. Their maximum force density is higher than electric cylinders, ceramic piezoactuators, and electrostatic actuators, and their work capacity is close to that of thermal actuators. This work demonstrates the hitherto untapped potential of ionic organic crystals for applications such as light-weight capacitors, dielectrics, ferroelectric tunnel junctions, and thermistors.

Heat-stimuli controllability of shape memory thermoplastic epoxy filaments by adding polyethylene glycol

This study prepared shape-memory thermoplastic epoxy (TEP)-polyethylene glycol (PEG) filaments for the first time, and the heat-stimuli controllability of shape memory function was innovatively endowed by adding PEG in an environmentally friendly way. PEG regulates the glass transition temperature of PEG-modified thermoplastic epoxy (TEP–PEG) without interfering with the polymerization reaction of epoxy. The melt spinning temperature of TEP–PEG is also reduced from 300 °C to 220 °C, and the spinning effect is improved. After PEG modification, Young's modulus of TEP–PEG filaments drawn from TEP–PEG pellets was higher at room temperature. The developed TEP–PEG filaments have excellent shape memory effect with high shape recovery rates of 93.1%–99.0%, and shape fixation rates ranging from 95.8% to 99.1% are also improved after PEG modification. Furthermore, TEP–PEG filaments have controllable stimuli temperatures of shape memory ranging from 69 °C to 105 °C. Additionally, the recovery stress of TEP–PEG filaments after PEG modification was increased to 1.77 MPa, and the recovery temperature of the maximum recovery stress is reduced from 97 °C to 58 °C as PEG content increases to 15 wt%. The problems of difficult melt processing and uncontrollable stimuli temperature for TEP were solved in this study. The developed TEP-PEG filaments with heat-stimuli controllability of the shape memory function demonstrated excellent thermal actuation capabilities and have shown greater application potential in thermal actuation, smart textiles, and artificial muscles.

A new design approach for thermal actuators based on topology optimization with stress constraints

This paper proposes a new approach for the design of thermal actuators using topology optimization. For the designs based on topology optimization, compliant mechanisms are required to have flexible, stiff, and sustained structures. To achieve this, conventional methods usually consider multiloading problems or use spring elements. In this work, a method that only considers one load case and does not use spring elements was developed by introducing an objective function that combines evaluation functions that provide necessary features for the actuators. This way, a structure with the same deformation mode of real phenomena could be derived with a low computational cost and without spring elements. In addition, the stress constraints on the thermal stress, which have not been widely discussed so far, were applied to show the structure with the considered strength characteristics. The study subject is topology optimization of an isotropic thermo-elastic model considering a thermo-mechanical problem. Finally, numerical examples for multiple conditions were performed to show that the proposed method can derive the desired optimal structure.

Thermally actuated micro-/nanoscale deformations for optical reconfigurations

The unique three-dimensional (3D) deformations caused by nano-kirigami have enabled a new degree of freedom for reconfigurable optics. Here, we demonstrate a facile nano-kirigami method that can create 3D deformed structures, which can flexibly manipulate optical properties using thermally actuated micro-/nanoscale deformations. By connecting four pairs of thermal actuators to the four sides of a gradient metasurface, large-angle beam steering (∼90°) can be achieved by adjusting the temperature of the actuators. The amplitude of circular dichroism can be adjusted by thermally actuating micro-/nanoscale deformations. The 2D-to-3D transformation of the curved arm structure on metallic substrate results in enhanced structural absorption, inducing an almost perfect absorption at specific wavelengths. Curved asymmetric structures can also be created by thermally actuated micro-/nanoscale deformations, which provides a novel method for cross-polarized light conversion. The proposed design with thermally actuated micro-/nanoscale deformations provides a new methodology to explore versatile reconfigurable functionalities.