With the continuous advancement of electronic devices, lightweight, flexible, and easily processable materials have gained substantial techno-commercial importance. Most electronic devices must possess a lightweight, high conductivity, high dielectric permittivity, low dielectric loss, and high breakdown strength. Hence, polymer-based piezoelectric materials are in great demand for design and development in energy storage, electromagnetic interference (EMI) shielding, and ultrafiltration applications. Among the piezoelectric polymers, poly­(vinylidene fluoride) (PVDF) with a predominantly polar β-phase is the most important. However, the main drawbacks of the PVDF matrix are its relatively low electrical conductivity and dielectric permittivity, and poor energy harvesting and EMI shielding performance. In this context, the incorporation of conductive nanofillers such as reduced graphene oxides, graphene quantum dots, and carbon nanotubes in the PVDF matrix has attracted considerable interest owing to their extraordinary properties. The final properties of these piezoelectric composites depend on the preparation methods, structural conformation, processing conditions, dispersion of nanofillers in the matrix, surface modification of fillers, and specific or nonspecific interaction of the fillers with the PVDF matrix. Herein, we have critically reviewed the formation mechanism of the electroactive β-phase in PVDF, the effects of nanofillers on the phase transformation of PVDF (dispersion and specific interaction), and the correlation of β-phase PVDF piezoelectric and dielectric properties with energy harvesting, EMI shielding, and membrane applications.

The spatial distribution of nanoparticles in a particular host polymer matrix can be improved by using brush coated nanoparticles. In this work we have grafted styrene-acrylonitrile (SAN) onto the surface of graphene oxide (GO) and investigated as to how the demixing temperature, morphology and volume cooperativity of PMMA/SAN blends are influenced. Grafting of polymer chains on the surface of nanoparticles usually involves the use of large amounts of solvents, many which are detrimental to the environment besides involving cumbersome processes. SAN-g-GO was prepared by a robust solvent-free strategy wherein the cyano group in SAN was replaced by oxazoline groups during melt mixing in the presence of zinc acetate and ethanol amine. These newly created oxazoline groups reacted with the COOH group of GO under melt extrusion resulting in grafting of SAN on the surface of GO sheets. The effect of SAN-g-GO nanoparticles on the demixing, local segmental motions and morphology evolution for different annealing times was carefully investigated in a classical LCST system, PMMA/SAN blend, using melt rheology, modulated DSC and AFM, respectively. The changes in viscoelastic behavior in the vicinity of demixing are investigated systematically for the control, and blends with GO and SAN-g-GO. Various models were used to gain insight into the spinodal decomposition temperatures of the blends. Interestingly, the demixing temperature determined rheologically and the spinodal decomposition temperature increased significantly in the presence of polymer grafted nanoparticles in comparison to the control and blends with GO. The evolution of the morphology, interfacial driven coarsening as a function of temperature and the localization of nanoparticles were assessed using atomic force microscopy. The cooperatively re-arranging regions estimated from calorimetric measurements begin to suggest enhanced dynamic heterogeneity in the presence of GO and SAN-g-GO in the blends. Taken together, our study reveals that the solvent-free approach of grafting SAN onto GO delays demixing, suppresses coalescence and alters cooperative relaxation in PMMA/SAN blends.

Advanced functional materials that are highly efficient in shielding electromagnetic radiation and sensing applications are primarily lightweight polymeric materials. In recent years, several research works on the development of polymer‐based sensors and electromagnetic interference (EMI) shielding materials have been reported. Cellulosic materials are extensively investigated for fabricating EMI shielding gadgets and sensors. Cellulose is a naturally abundant renewable polymeric material, and the EMI shielding, and sensing performances of cellulose‐based materials depend on their conductive network architecture. Incorporating conducting nanofillers can improve the conductivity of the cellulose matrix in composites. However, a comprehensive understanding of the electrical response of nanofillers in cellulose‐based composites is necessary for the design of EMI shielding materials and sensor devices. Therefore, this work provides a critical overview of the types of processing methods used, an insight into the effects of incorporating conductive nanofillers on the architectural structure of cellulose, and the obtained shielding and sensing properties of the cellulose‐based composites. This article is expected to provide guidelines for developing sustainable polymer materials for advanced applications in the future.

Polymer blending is an effective method which can be used to fabricate new versatile materials with enhanced properties. Blending of two polymers can either result in a miscible or immiscible...

A suitable polymer matrix and well dispersed conducting fillers forming an electrically conducting network are the prime requisites for modern age electromagnetic shield designing. An effective polymer-based shield material is designed that can attenuate 99.9% of incident electromagnetic (EM) radiation at a minimum thickness of <0.5 mm. This is accomplished by the choice of a suitable partially crystalline polymer matrix while comparing non-polar polypropylene (PP) with polar polyvinylidene fluoride (PVDF) and a best suited filler nanomaterial by comparing different types of carbon nanotubes such as; branched, single-walled and multi-walled carbon nanotubes, which were added in only 2 wt %. Different types of interactions (polar-polar and CH-π and donor-acceptor) make b-MWCNT more dispersible in the PVDF matrix, which together with high crystallinity resulted in the best electrical conductivity and electromagnetic shielding ability of this composite. This investigation additionally conceals the issues related to the thickness of the shield material just by stacking individual thin nanocomposite layers containing different carbon nanotube (CNT) types with 0.3 mm thickness in a simple manner and finally achieves 99.999% shielding efficiency at just 0.9 mm thickness when using a suitable order of the different PVDF based nanocomposites.