Application Cases

Introduction

Soft actuators are evolving from single deformation functions toward multifunctional integration, among which drive-luminescence coupled devices hold significant application prospects in biomimetics, information encryption, and display. However, existing dual-functional devices typically rely on multiple stimulation sources to synergistically achieve actuation and luminescence, featuring complex structures and slow responses, which constrain their rapid and controllable applications. Electrical stimulation, due to its high controllability, provides a potential pathway for the synchronous realization of actuation and luminescence. Dielectric elastomer actuators (DEAs) and electroluminescence (EL) devices possess natural compatibility in laminated configurations and electric field driving mechanisms. However, their operating voltages are severely mismatched (kilovolt-level vs. hundred-volt-level), and DEAs require pre-stretching and rigid frame support, while the introduction of phosphor powder degrades the mechanical and electrical properties of the elastomer. Therefore, how to reduce the driving voltage through structural innovation, optimize the phosphor doping amount to balance actuation performance and luminescence efficiency, and achieve rapid, large-deformation, stable out-of-plane actuation and luminescence synergistic output under single electrical signal excitation has become a critical technical problem urgently requiring breakthrough in this field, and also represents the core challenge for realizing the intelligent, biomimetic, and multifunctional development of soft actuators.

This study belongs to an important branch under the category of dielectric elastomer actuators (DEAs) that achieves out-of-plane bending actuation and functional integration through structural innovation and material compositing. Its core connections are manifested as follows: it inherits the classic Maxwell stress driving principle of DEAs, yet breaks through the traditional limitations of in-plane expansion and pre-stretching. By utilizing an asymmetric electrode structure design, large out-of-plane bending actuation without pre-stretching is realized (curvature of 4.71 cm⁻¹). Meanwhile, by doping ZnS:Cu²⁺ phosphor powder into the dielectric elastomer, the same functional layer possesses both dielectric and luminescent properties. The critical gap between the kilovolt-level driving voltage of DEAs and the hundred-volt-level operating voltage of electroluminescence is bridged through the asymmetric structure. Ultimately, rapid (~160 ms) and stable (20,000 cycles) synchronous output of actuation and luminescence is achieved under single electrical signal excitation. This research does not overturn the fundamental principles of DEAs; rather, within the classical framework, it addresses common bottlenecks of conventional DEAs in multifunctional integration, low-voltage driving, and large out-of-plane deformation through two pathways—structural design (asymmetric electrodes) and material optimization (phosphor doping)—providing a feasible paradigm for expanding DEA technology toward practical applications such as biomimetic robots, intelligent displays, and multifunctional devices.

Research Direction

Composite Functional Materials,Device Structural Design,Electromechanical-Optical Coupling Mechanism,Optimization of Actuation and Luminescence Performance,Applications in Biomimetic Soft Robotics,Multifunctional Array Display Technology.

Experimental objective

A dual-functional elastomer was obtained by doping an appropriate amount of luminescent powder into the dielectric elastomer. An asymmetric electrode structure was then designed, enabling the dual-functional device to simultaneously achieve large out-of-plane actuation and stable luminescence under a single electrical signal.

Testing equipment

385 nm UV curing chamber，Vacuum degassing apparatus，Extended depth-of-field microscope (DVM6, Leica)，Universal testing machine (Instron 5969)，Laser engraving machine (Venus VII-12, SYNRAID)，Spectrometer (SEK)，High-sensitivity optical power meter (2936-R, Newport)，Function generator (33622A)，High-voltage amplifier (ATA-7050, Aigtek)，Fourier transform infrared spectrometer (FTIR)，Broadband dielectric spectroscopy system，Infrared thermal imager.

Experimental process

An appropriate amount of luminescent powder was added to the elastomer precursor solution. After thorough stirring and vacuum degassing, the mixture was poured into a fixed mold and photocured to obtain a dual-functional elastomer. Silver nanowire electrodes of varying thicknesses were fabricated by vacuum filtration and then transferred to both sides of the dual-functional elastomer via transfer printing, forming a dual-functional device with an asymmetric structure. Driven by the electrical signal output from the signal generator and voltage amplifier, the device simultaneously achieved actuation and luminescence.

Figure1 Material preparation process.

Figure2  experimental setup.

Experimental results

 Through the waveform generator and signal amplifier, electrical signals with different voltages and frequencies can be output. The dual-functional dielectric elastomer actuator exhibits different actuation and luminescence effects under varying voltages and frequencies. Specifically, the actuation performance increases with increasing voltage but decreases with increasing frequency. The luminescence performance increases with both increasing voltage and increasing frequency.

Figure3 The curves of the bending curvature and luminous power of ELDEA-0.25 as a function of the electric field, and the relationship between

the actuation curvature of the same type of bending DEA with the electric field.

Figure4 Bending curvature and luminous power at different frequencies. (f) Bending

fatigue test under 10 Hz and 12.5 MV/m, running continuously for 20 000 times.

The effectiveness of the amplifier in this experiment

1. Amplify the low-voltage control signal output from the function generator to hundreds-of-volts to kilovolt-level high voltage, providing the required alternating electric field excitation for the ELDEA.

2. Support the application of different electric field strengths (e.g., 5 MV/m to 18.5 MV/m) and waveforms for testing the bending curvature, luminescence power, and frequency response characteristics of the actuator.

3. Cooperate with multiple waveform outputs such as square waves and sine waves to study the temporal response behavior of actuation and luminescence under dynamic electric field switching (e.g., transient luminescence pulses and creep deformation).

4. Provide high-voltage signals over a wide frequency range (0.5–15 Hz and 1000 Hz high frequency) to respectively achieve low-frequency large-bending actuation, high-frequency strong luminescence, and frequency-tunable color switching functions.

5. In biomimetic butterfly and array display applications, provide programmable voltage signals for each independent "pixel" or drive unit, achieving multi-channel independent control and coordinated motion.

6. Through stable high-voltage signal output, support durability and environmental stability testing of the actuator under 20,000 cycles, different temperature and humidity conditions, and illumination conditions.

Application fields

Biomimetic Soft Robots,Multi-Environment Intelligent Displays,Dynamic Optical Camouflage and Encryption,Human-Machine Interaction and Haptic Feedback,Micro Aerial Vehicles and Insect-Scale Robots.