Electro-thermo-mechanical modeling of shape memory polymers filled with nano-carbon powder

Generally, adding the electroconductive fillers into the polymer matrix is a popular approach to endow the shape memory polymers (SMPs) with electroconductivity. Therefore, the shape memory effects (SMEs) of thermally induced SMPs can also be triggered by the electrical current. In essence, both the thermally activated and electrically activated SMEs share the same driving mechanism without considering the effect of heat conduction. In the paper, the constitutive model for the thermally induced SMPs filled with nano-carbon powder is briefly introduced. Then, a modified model is developed to characterize the effects of filler, deformation, and moisture on the electrical conductivity for the first time. After developing the correlation of electric field with Joule heat, the simulation is executed to display the free recovery of the shape memory polymer composites (SMPCs) with different filler content. It is found that the recovery ratio decreases with the increase of carbon powders for the SMPCs with filler content above the percolation threshold. Besides, a good recovery ratio can also be achieved through the application of a lower voltage.

Shape memory textiles – technological background and possible applications

While shape memory alloys (SMAs) and shape memory polymers (SMPs) can already be found in diverse applications, shape memory textiles are less often used. Nevertheless, they are regularly investigated. Typical ways to produce shape memory textiles (SMTs) are introducing shape memory wires, printing shape memory polymers on them (“4D printing”), or using textile materials such as poly(lactic acid) (PLA) which show shape memory properties on their own. This review gives a brief overview of these technological possibilities and possible applications of shape memory textiles.

Composites of functional polymers: Toward physical intelligence using flexible and soft materials

Materials that can assist with perception and responsivity of an engineered machine are said to promote physical intelligence. Physical intelligence may be important for flexible and soft materials that will be used in applications like soft robotics, wearable computers, and healthcare. These applications require stimuli responsivity, sensing, and actuation that allow a machine to perceive and react to its environment. The development of materials that exhibit some form of physical intelligence has relied on functional polymers and composites that contain these polymers. This review will focus on composites of functional polymers that display physical intelligence by assisting with perception, responsivity, or by off-loading computation. Composites of liquid crystal elastomers, shape-memory polymers, hydrogels, self-healing materials, and transient materials and their functionalities are examined with a viewpoint that considers physical intelligence. Graphic Abstract