Versatile Strategy for Electrophoretic Deposition of Polyvinylidene Fluoride-Metal Oxide Nanocomposites

Polyvinylidene fluoride (PVDF) is an advanced functional polymer which exhibits excellent chemical and thermal stability, and good mechanical, piezoelectric and ferroelectic properties. This work opens a new strategy for the fabrication of nanocomposites, combining the functional properties of PVDF and advanced inorganic nanomaterials. Electrophoretic deposition (EPD) has been developed for the fabrication of films containing PVDF and nanoparticles of TiO2, MnO2 and NiFe2O4. An important finding was the feasibility of EPD of electrically neutral PVDF and inorganic nanoparticles using caffeic acid (CA) and catechol violet (CV) as co-dispersants. The experiments revealed strong adsorption of CA and CV on PVDF and inorganic nanoparticles, which involved different mechanisms and facilitated particle dispersion, charging and deposition. The analysis of the deposition yield data, chemical structure of the dispersants and the microstructure and composition of the films provided an insight into the adsorption and dispersion mechanisms and the influence of deposition conditions on the deposition rate, film microstructure and composition. PVDF films provided the corrosion protection of stainless steel. Overcoming the limitations of other techniques, this investigation demonstrates a conceptually new approach for the fabrication of PVDF-NiFe2O4 films, which showed superparamagnetic properties. The approach developed in this investigation offers versatile strategies for the EPD of advanced organic-inorganic nanocomposites.

Boosted dielectric performance of organic‐inorganic nanocomposites based on BaTiO3 via 2D TiO2 templates

Organic-inorganic hybrid dielectrics composed of nanoscale ceramic fillers in polymer matrices have attracted considerable attention because they can overcome the inherent limitations such as the low dielectric constant, high dielectric loss, and low film density associated with mechanically flexible pristine polymer materials. Barium titanate (BaTiO3), a representative perovskite-based material with a high permittivity, is suitable for applications as nanofillers in nanocomposite dielectrics. X-ray diffraction combined with Raman analysis suggest that a two-step hydrothermal synthesis, which uses synthesized TiO2 nanosheets as a template, is an effective method for the synthesis of pure BaTiO3 nanoparticles compared with other methods. Ultrasonic treatment is employed to disperse BaTiO3 nanoparticles with different concentrations in polyvinyl alcohol (PVA) polymer, and the dielectric performance of the nanocomposite films has been examined. In this study, 20 wt% BaTiO3-PVA nanocomposite dielectric showed superior capacitance and dielectric constant performance, i.e., five times higher than that of the pristine PVA.

Palygorskite-Based Organic–Inorganic Hybrid Nanocomposite for Enhanced Antibacterial Activities

A synergistic antibacterial strategy is effective in enhancing the antibacterial efficacy of a single antibacterial material. Plant essential oils (PEOs) are safe antibacterial agents. However, some of their characteristics such as intense aroma, volatility, and poor thermal stability limit their antibacterial activity and applications. In this paper, five kinds of PEOs were incorporated onto ZnO/palygorskite (ZnO/PAL) nanoparticles by a simple adsorption process to form organic–inorganic nanocomposites (PEOs/ZnO/PAL) with excellent antibacterial properties. TEM and SEM analyses demonstrated that ZnO nanoparticles uniformly anchored onto the surface of rod-like PAL, and that the structure of ZnO/PAL maintained after the incorporation of ZnO nanoparticles and PEOs. It was found that carvacrol/ZnO/palygorskite (CAR/ZnO/PAL) exhibited higher antibacterial activities than other PEOs/ZnO/PAL nanocomposites, with minimum inhibitory concentration (MIC) values of 0.5 mg/mL and 1.5 mg/mL against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), respectively. Moreover, the antibacterial efficiency of CAR/ZnO/PAL nanocomposites was superior to that of ZnO/PAL and pure CAR, demonstrating the synergistic effect that occurs in the combined system. PAL serving as a carrier for the combination of organic PEOs and ZnO nanoparticles is an effective strategy for enhanced, clay-based, organic–inorganic hybrid antibacterial nanocomposites.

ANALYSIS OF THE INFLUENCE OF THE NATURE OF THE FILLER SURFACE ON THE PROPERTIES OF HYBRID ORGANIC-INORGANIC NANOCOMPOSITES BASED ON EPOXY OLIGOMER

The aim of this work was to investigate the influence of the chemical nature of the filler surface on the properties of hybrid organo-inorganic nanocomposites based on epoxy oligomer ED-20 in the presence of nanoscale functional filler of inorganic origin - aerosil, with different surface nature. The influence of the chemical nature of the surface of highly dispersed aerosil on the thermal properties of nanocomposites based on epoxy oligomer ED-20 has been studied. The peculiarities of the process of thermooxidative destruction have been studied. It is shown that the introduction of highly dispersed aerosil in the amount of 0.5% in the epoxy matrix does not lead to changes in the thermal properties of composites, and the nanofiller in the amount of 5% improves thermal stability of composites. The kinetics of the curing process of epoxy nanocomposites was studied by IR-spectroscopy. The influence of the presence of functional groups on the nanofiller surface on rate and the degree of conversion of epoxy groups was determined. The presence of hydroxyl groups on the surface of A-300 contributes to the rate of conversion of epoxy groups to a greater extent, compared with aerosil with a modified surface, which contains on the surface methyl groups capable of blocking reactive groups. It is established that the rate of conversion of epoxy groups in the presence of aerosil decreases in the range of ED-20 > ED-20 + A-300 > ED-20 + AM-300. The sorption properties of epoxy nanocomposites have been studied. It is established that the sorption process proceeds at a higher rate when the matrix is filled with unmodified aerosil. The mechanism of influence of the chemical nature of the filler surface and content on formation and properties of epoxy nanocomposites is discussed.

Functionalized Organic–Inorganic Liposome Nanocomposites for the Effective Photo-Thermal Therapy of Breast Cancer

Organic–inorganic nanocomposites for photothermal therapy of cancers emerged as a promising strategy against malignant tumors. However, it is still a big challenge to develop a nanocomposite system that can maximize the synergistic photo-thermal therapy effect as well as preserve high stability for simultaneous delivery of the chemotherapeutic drugs and photo-thermal agents. Here, we have exploited an organic liposome containing inorganic core for co-loading the aggregates of bovine serum albumin (BSA), indocyanine green (ICG), and doxorubicin (DOX), abbreviated as BID-liposomal nanocomposites. The three kinds of substances were aggregated in the core of liposomal nanocomposites through hydrophobic and electrostatic interactions. In vitro characterization shows that BID-liposomal nanocomposites were spherical nanoparticles with size of 30–50 nm and good storage stability. Moreover, BID-Liposomal nanocomposites illustrate the strongest cytotoxicity among all the formulations against murine 4T1 tumor cells. In breast cancer-bearing mouse models, BID liposomes lead to significant improvements in tumor inhibition effects with no obvious toxicity. Therefore, the BID-liposomal nanoparticle is believed to be a promising strategy for chemo-photo-thermal therapy against cancers.

A NOVEL ROUTE FOR THE FORMATION OF GAS SENSORS

The rapid development of conductive polymers shows great potential in temperature chemical gas detection as their electrical conductivity is often changed upon spotlight to oxidative or reductive gas molecules at room temperature. However, the relatively low conductivity and high affinity toward volatile organic compounds and water molecules always exhibit low sensitivity, poor stability and gas selectivity, which hinder their practical gas sensor applications. In addition, inorganic sensitive materials show totally different advantages in gas sensors like high sensitivity, fast response to low concentration analytes, high area and versatile surface chemistry, which could harmonize the conducting polymers in terms of the sensing individuality. It seems to be a good option to combine inorganic sensitive materials with polymers for gas detection for the synergistic effects which has attracted extensive interests in gas sensing applications. In this appraisal the recapitulation of recent development in polymer inorganic nanocomposites-based gas sensors. The roles of inorganic nanomaterials in improving the gas sensing performances of conducting polymers are introduced and therefore the progress of conducting polymer inorganic nanocomposites including metal oxides, metal, carbon (carbon nanotube, graphene) and ternary composites are obtainable. Finally, conclusion and perspective within the field of gas sensors incorporating conducting polymer inorganic nanocomposites are summarized. Keywords: Gas sensor, conducting polymer, polymer-inorganic nanocomposites; conducting organic polymers nanostructure, synergistic effect, polypyrrole (PPY), polyaniline (PANI).