Significantly Enhanced Electromechanical Performance of PDMS Crosslinked PVDF Hybrids

PANI-wrapped BaFe12O19 and SrFe12O19 with rGO composite materials for electromagnetic interference shielding applications

We report electromagnetic interference (EMI) shielding efficiency in the PANI-wrapped BaFe₁₂O₁₉ and SrFe₁₂O₁₉ with rGO composites. Barium and strontium hexaferrites were synthesized using the nitrate citrate gel combustion method. These hexaferrites were polymerized in situ with aniline. The PANI-coated ferrite-based composite materials were developed along with reduced graphene oxide (rGO) in acrylonitrile butadiene styrene (ABS) polymer, and their shielding effectiveness was assessed in X-band frequency range (8.2-12.4 GHz). The reflection (SE_R) and absorption (SE_A) mechanism of shielding effectiveness was discussed with the different rGO concentrations. The results reveal that 5 wt% of rGO with PANI-coated barium and strontium hexaferrite polymer composites exhibit shielding efficiency of 21.5 dB and 19.5 dB, respectively, for 1 mm thickness composite. These hexaferrite polymer-based composite materials can be used as an attractive candidate for EM shielding materials in various technological applications.

Progress in Microtopography Optimization of Polymers-Based Pressure/Strain Sensors

Due to the wide application of wearable electronic devices in daily life, research into flexible electronics has become very attractive. Recently, various polymer-based sensors have emerged with great sensing performance and excellent extensibility. It is well known that different structural designs each confer their own unique, great impacts on the properties of materials. For polymer-based pressure/strain sensors, different structural designs determine different response-sensing mechanisms, thus showing their unique advantages and characteristics. This paper mainly focuses on polymer-based pressure-sensing materials applied in different microstructures and reviews their respective advantages. At the same time, polymer-based pressure sensors with different microstructures, including with respect to their working mechanisms, key parameters, and relevant operating ranges, are discussed in detail. According to the summary of its performance and mechanisms, different morphologies of microstructures can be designed for a sensor according to its performance characteristics and application scenario requirements, and the optimal structure can be adjusted by weighing and comparing sensor performances for the future. Finally, a conclusion and future perspectives are described.

Graphene templated growth of copper sulphide 'flowers' can suppress electromagnetic interference

With increasing usage of electronic gadgets in various fields, the problem of electromagnetic interference (EMI) has become eminent. To suppress this interference, lightweight materials that are non-corrosive in nature and easy to fabricate, design, integrate and process are in great demand. In the present study, we have grown copper sulphide 'flowers' on graphene oxide by a facile one pot hydrothermal technique. The growth time of the "flower-like" structure was optimised based on structural (XRD) and morphological analysis (SEM). Then, the as-prepared structures were dispersed in a PVDF matrix using melt blending. The bulk AC electrical conductivity and EMI shielding ability of the prepared composite were assessed, and it was observed that the nanocomposites exhibited an EMI shielding effectiveness up to -25 dB manifesting in 86% absorption of the incoming EM waves at a thickness of only 1 mm. Moreover, it was also observed that addition of hybrid nanoparticles has a better effect on the electromagnetic (EM) shielding performance compared to when the nanoparticles are added separately in terms of both total shielding effectiveness as well as absorption performance. A minimum skin depth of 0.38 mm was observed in the case of the hybrid nanostructure.

Actuation Behavior of Multilayer Graphene Nanosheets/Polydimethylsiloxane Composite Films

The graphene nanosheets (GNS)/polydimethylsiloxane (PDMS) composite films with out-of-plane dielectric actuation behavior were prepared through a layer-by-layer spin coating process. The GNS-PDMS/PDMS composite films with 1~3 layers of GNS-PDMS films were spin coated on top of the PDMS film. The dielectric, mechanical, and electromechanical actuation properties of the composite films were investigated. The dielectric constant of the GNS-PDMS³/PDMS composite film at 1 kHz is 5.52, which is 1.7 times that of the GNS-PDMS¹/PDMS composite film. The actuated displacement of the GNS-PDMS/PDMS composite films is greatly enhanced by increasing the number of GNS-PDMS layers. This study provides a novel alternative approach for fabricating high-performance actuators with out-of-plane actuation behavior.