Latest Advances in Development of Smart Phase Change Material for Soft Actuators

Abstract

Using a phase change material (PCM) to convert energy as a specific medium can date back to three hundred years ago, when steam engines took advantage of water that can evaporate into water vapor to convert energy. PCMs enable themselves to absorb, store, and release energies actively to maintain the object temperature on the basis of ambient temperature. PCMs have a robust 20% compound annual growth rate in the global smart materials market. [1] To this date, extensive works have been conducted to investigate the application of smart PCMs in various scientific, technological, and industrial fields, including energy storage, heat exchanger, [2] water treatment, [3] thermal management of electrical equipment, [4] textile and fabrics, [5,6] biomedical and biocarrier systems, and so on. It has become especially popular in the fields of architectonics and textile manufacture. The latest study by Tung et al. [7] proposed to utilize nanotechnology to fabricate PCMs to develop a novel smart concrete, while PCM-treated textiles have been widely used in apparel and home products, [8] in particular a precool vest invented by Australian Institute of Sport at the 2004 Athens Olympic Games. [9] PCM composites can be formed with additional or modified properties with six "multifeatures" that are multimaterial, multisystem, multimodulus, multiscale, multifunction, and multidimensional (Figure 1). Impregnating PCM into mechanically stable porous materials can improve stability, while adding metallic pieces or foams [10] can increase thermal conductivity; but it is also limited by the convection reduction or elimination in the liquid phase through combining with fast-response materials into PCM. To maintain the mechanical properties of a material, the characteristic dimension of the internal structure of the composite material is at or below the millimeter scale.

Design principles for a single-process 3D-printed stacked dielectric actuators — Theory and experiment

“…1. The dielectric actuation mechanism using the Maxwell-stress approach for the (33) direction is defined as [83]:…”

Magnetic field–driven particle assembly and jamming for bistable memory and response plasticity

“…Artificial stimulus-responsive materials (1-4) and shape-memory and shape-morphing materials (5)(6)(7)(8) have already witnessed considerable scientific progress and have been implemented in technologically relevant applications based on their switchable properties. Their properties are, however, limited to fixed states under repeated stimuli, and they do not dynamically adapt or evolve to new states.…”

“…The classic stimulus-responsive materials involve fixed states, and the response always remains the same upon repeated stimuli cycling. In the shape memory materials (5)(6)(7)(8), in the simplest case, there is a second imposed condition or stimulus that allows preparing the material in another kinetically trapped state. This facilitates keeping the materials in the temporary state before releasing them back to the original state by exposing another stimulus.…”

Fast Solidification of Pure Gallium at Room Temperature and its Micromechanical Properties

“…of the solidification process and the mechanical and chemical properties of the solidified gallium are still little known. As known that the solidification of materials is a key factor to know materials' properties, which could be used as phase-change materials and valuable in many research areas, such as energy storage, [2,27,28] biomedical engineering, [10,11] surface patterning, [24] even soft robotics, [13,14,29] material science. [30,31] Thus, in-depth understanding of the solidification process plays a crucial role in both application of materials and the development of new alloys or composites.…”