Smart material

About: Smart material is a research topic. Over the lifetime, 3704 publications have been published within this topic receiving 74280 citations. The topic is also known as: intelligent material & responsive material.

Recent progress in 4D printing of stimuli-responsive polymeric materials

Abstract: 4D printing is proposed based on the additive manufacturing of stimuli-responsive materials and structures, which can realize shape changing upon external stimuli. This article reviews the 4D printing methods and actuating performances of 4D printing structures based on shape memory polymers, hydrogels, liquid crystal elastomers, and electroactive polymers. This article shows that the shape morphing properties of single materials are limited, while 4D printing of composites can integrate the various driving modes of different smart materials. In the end, challenges facing 4D printing such as broadening the scope of smart materials, improving printing processes, the compatibility of printing different materials have been discussed.

Flexible Photonic Crystal Material for Multiple Anticounterfeiting Applications

Abstract: In this study, a nanoimprinting method was introduced to fabricate polycarbonate films with transparent and flexible photonic crystal (FPC) structures. The fabricated flexible polymer films display a full-color grating because of the nanohemispherical structures on the surface. Through the Bragg diffraction formula, it was confirmed that the FPC polymer films transfer a part of the light energy to the second-order diffraction spectrum. Furthermore, the full-color grating properties can be modulated through geometric deformation because of the film’s elasticity. Additionally, anticounterfeiting features were also successfully achieved when the polymer films were either engraved with drawings and bent or patterned with fluorophores, which can be revealed under ultraviolet light. The most important aspect of this research is that the preparation of this FPC-structured polymer film is inexpensive and convenient, enabling the mass production of a new generation of smart materials.

Biopolymer-based strategies in the design of smart medical devices and artificial organs.

Abstract: Advances in regenerative medicine and in modern biomedical therapies are fast evolving and set goals causing an upheaval in the field of materials science. This review discusses recent developments involving the use of biopolymers as smart materials, in terms of material properties and stimulus-responsive behavior, in the presence of environmental physico-chemical changes. An overview on the transformations that can be triggered in natural-based polymeric systems (sol-gel transition, polymer relaxation, cross-linking, and swelling) is presented, with specific focus on the benefits these materials can provide in biomedical applications.

Dynamic performance of dielectric elastomers utilized as acoustic actuators

Abstract: We report on the frequency dependent behavior of dielectric elastomer actuators (DEA). The introduced smart material actuators consist of 3M™’s elastomer VHB™4905 (9469) and a compliant, sputtered copper electrode on each side. The presented experiments on these compounds contain the active tuning of their resonance frequency and their application as acoustic actuators. We are able to decrease the membranes’ eigenfrequency by 30% with an electrical offset potential. Alternatively, if an alternating signal is applied, sound pressure levels up to 130 dB in an enclosed volume of 28 ccm are achieved. In order to verify the results, a numerical simulation is introduced incorporating the two physical fields involved: electrical and mechanical.