A novel miniaturized paraffin actuator with Peltier-controlled cooling and graphene thermal conductivity enhancers

Paraffin-based microactuators show great potential in the field of phase change materials actuators owing to their high mechanical work capacity and large thermal expansion. In recent years, researchers have directed efforts toward enhancing the response times of these systems, by mixing paraffin with thermal conductivity enhancers or by optimizing their designs. However, no previous research has focused on improving the cooling time of a paraffin actuator, which is essential for ensuring faster cyclic performance and adaptable thermal control in environments where temperature fluctuates. In this study, we present the first miniaturized thermoelectric cooler (µTEC)-paraffin-based actuator. This design utilizes the µTEC to control the phase change of paraffin, by heating or cooling it on demand. Furthermore, we investigated the use of graphene nano-platelets (GnPs) as a thermal conductivity enhancer and its effect on design performance. The system featured an aluminum cavity filled with a paraffin composite formulation, a µTEC device and a copper heat sink. The results showed that the presence of a µTEC could enable not only cyclic actuation, but also reduced the actuator reset time to approximately 20% of the original duration. The device also demonstrated a peak work density and efficiency around 25.6 kJ/m 3 and 17.8 × 10 -6 , respectively. These results place our actuator system among the highest-performing flexible membrane-based paraffin microactuators reported in the literature with the additional benefit of controlled and fast cooling. • First miniaturized µTEC-paraffin actuator enabling active heating and controlled cooling. • Cost-effective fabrication using aluminum cavity and silicone membrane allows rapid, scalable assembly. • µTEC integration reduced reset time by 80%, improving actuation cycle speed. • Graphene nanoplatelets studied as thermal conductivity enhancers, improving thermal response while reducing volumetric expansion. • Actuator performance evaluated in displacement, force, work density, and efficiency; results comparable to state-of-the-art paraffin microactuators.