Synthesis, Characterization and Application of Hybrid Composites

In the last century, polymers have dominated the materials market, and in the later part of the 20th century, the possibility to further improve their properties and expand their applications was explored by combining polymers with reinforcing elements [...]

Catauro et al., by using the sol-gel method, prepared silica-based hybrid organic/inorganic amorphous composites with polycaprolactone [8]. They spectroscopically characterized the obtained composites and assessed their bioactivity and antimicrobial behavior, aiming at proposing them for bone implants.
Poly(lactic acid) (PLA)-based biocomposites reinforced with flax fibers were designed and prepared by Seggiani and coworkers by melt blending and a co-rotating conical twin-screw extruder. For the obtained materials, the Italian researchers observed good matrix/fiber adhesion and mechanical behavior in terms of break stress and composite stiffness [9].
Lan and colleagues, by mixing ferromagnetic nickel micro-powders with polyurethane (PU) shape memory polymer (SMP)/dimethylformamide solution, prepared a micron-sized protrusive PU SMP composite, curing the mixture under a low magnetic field [10]. Morphology and thermal tests were carried out by the authors to show the hybrid composites' potential applications for micro-electro-mechanical systems (MEMS) and biomedical devices.
Polydimethylsiloxane (PDMS)-based composites were fabricated by Sheng et al. to study their optical transmittance properties. With a simple production process, the Chinese researchers checked the materials' transmittance by varying the microcrystalline graphite powder concentration or the composite film's thickness, thus obtaining a wide range of transmittance properties [11].
Quan and coworkers designed a new hybrid catalyst based on activated carbon (AC)-supported sulfonated cobalt phthalocyanine (AC-CoPcS) [12]. Firstly, they spectroscopically investigated the prepared catalyst to characterize its structure and then its catalytic performance, finding superior behavior in terms of yield and purity with good industrial application prospects.
The first of the three reviews in this Special Issue is by Samal and colleagues, who present the most outstanding advances in the rheological performance of magneto-rheological elastomer (MRE) composites. They focus on filler distribution, arrangement and wettability within elastomer matrices, and their contribution towards the performance of the mechanical response when subjected to a magnetic field are evaluated. Particular attention is devoted to the understanding of their internal micro-structures, filler-filler adhesion, filler-matrix adhesion and the viscoelastic behavior of the MRE composite under static (valve), compressive (squeeze) and dynamic (shear) modes [13].
A short review, on the effect of surfactants on the mechanico-thermal properties of polymer nanocomposites, was then proposed by Shamsuri and Jamil [14], highlighting polymer nanocomposites as a function of the surfactants used in their modification, namely surfactant-modified inorganic nanofiller/polymer nanocomposites and surfactant-modified organic nanofiller/polymer nanocomposites. The effect of surfactants on their mechanical and thermal properties is also shortly reviewed, with an attempt to capture the interest of the polymer composite researchers and encourage the further enhancement of new theories in this research field.
Finally, Qin et al., focus their attention on the progress in hybrid solar cells based on solution-processed organic and semiconductor nanocrystals, analyzing perspectives on the device design [15]. They give a brief introduction to the progress on solution-processed organic/inorganic semiconductor hybrid solar cells, including a summary of the development of hybrid solar cells in recent years, the strategy of creating hybrid solar cells with different structures and the incorporation of new organic hole transport materials, with new insights into device processing for high efficiency.

Conflicts of Interest:
The author declares no conflict of interest.