Using a pulsed laser ablation system, core–shell [email protected] nanoparticles ([email protected] NPs) were efficiently synthesized and incorporated into a polymeric nanofibrous cellulose acetate (CA)/polyvinylidene fluoride (PVDF) solution prior to electrospinning. Highly crystalline [email protected] NPs were formed in a spherical core/shell configuration with core and shell diameters of 10.5 nm and 25 nm, respectively. The networked scaffolds were decorated with micro-distensions with lengths ranging from 2.8 to 4.3 μm at the lowest [email protected] NPs content. Cell viability analysis confirmed the high biocompatibility of the produced scaffolds, with survival ratios around 91.1 ± 3.4% and 88.2 ± 4.3% at the lowest and highest concentrations of [email protected] NPs, respectively. Obviously, the cells spread and proliferated significantly through the nanofibers. Moreover, the cells not only grew on the surface, but also connected through the deeply porous interior of the nanoparticles. The compositions of these nanofibrous scaffolds can be manipulated to realize a new design for the dressing and healing of wounded tissues.
Abstract In this study, blends of low-density polyethylene (LDPE)/aluminum nitride (AlN) ceramic nanocomposites have been prepared through melt blending technique. Increased loading of AIN leads to reduction in tensile properties but improvement in rheological property (storage modulus). The rheological behavior tends to become unique at higher frequencies (≥10 rad/s). Differential scanning calorimetry (DSC) results show that the total crystallinity has decreased with the increase in AlN loading in the composites. It is seen that there is an improvement in electrical conductivity, dielectric constant, and flammability properties with the addition of AlN in the nanocomposites. The experimental data of tensile modulus, electrical conductivity, and dielectric constant have been fitted with some available theoretical models to check the models’ applicability for the present composite systems. Results show that only Nicolais-Nicodemo model, McCullough model, and Rahaman-Khastgir model are applicable for predicting the tensile modulus, electrical conductivity, and dielectric constant of the composites, respectively.
Abstract Herein, fluorescent conducting tautomeric polymers (FCTPs) are developed by polymerizing 2‐methylprop‐2‐enoic acid (MPEA), methyl‐2‐methylpropenoate (MMP), N ‐(propan‐2‐yl)prop‐2‐enamide (PPE), and in situ‐anchored 3‐( N ‐(propan‐2‐yl)prop‐2‐enamido)‐2‐methylpropanoic acid (PPEMPA). Among as‐synthesized FCTPs, the most promising characteristics in FCTP3 are confirmed by NMR and Fourier transform infrared (FTIR) spectroscopies, luminescence enhancements, and computational studies. In FCTP3, ─ C(═O)NH ─ , −C(═O)N<, ─ C(═O)OH, and ─ C(═O)OCH3 subluminophores are identified by theoretical calculations and experimental analyses. These subluminophores facilitate redox characteristics, solid state emissions, aggregation‐enhanced emissions (AEEs), excited‐state intramolecular proton transfer (ESIPT), and conductivities in FCTP3. The ESIPT‐associated dual emission/AEEs of FCTP3 are elucidated by time correlated single photon counting (TCSPC) investigation, solvent polarity effects, concentration‐dependent emissions, dynamic light scattering (DLS) measurements, field emission scanning electron microscopy images, and computational calculations. The cyclic voltammetry measurements of FCTP3 indicate cumulative redox efficacy of ─ C(═O)OH, ─ C(═O)NH ─ /−C(═O)N<, ─ C( ─ O ─ )═NH+ ─ / ─ C( ─ O ─ )═N+, and ─ C(═N)OH functionalities. In FCTP3, ESIPT‐associated dual‐emission enable in the selective detection of Cr(III)/Cu(II) at λ em1 / λ em2 with the limit of detection of 0.0343/0.079 ppb. The preferential interaction of Cr(III)/Cu(II) with FCTP3 (amide)/FCTP3 (imidol) and oxidation/reduction of Cr(III)/Cu(II) to Cr(VI)/Cu(I) are further supported by NMR‐titration; FTIR and X‐ray photoelectron spectroscopy analyses; TCSPC/electrochemical/DLS measurement; alongside theoretical calculations. The proton conductivity of FCTP3 is explored by electrochemical impedance spectroscopy and I – V measurements.
Electrical and dielectric properties of poly(vinyl alcohol) (PVA) films, and PVA/starch blend and its nanocomposites with graphene were investigated. The tested materials were prepared via solution mixing and an evaporative casting technique using glycerol as a plasticizer. Differential scanning calorimetric (DSC) measurement data was used to calculate the percentage of crystallinity and glass transition temperature ( ). Distribution of starch and graphene in the PVA matrix was determined from field emission scanning electron microscopy (FESEM). Effects of the plasticizer and graphene loading on the DC and AC electrical conductivities of the PVA/starch blend were studied. The impact of graphene loadings on the dielectric permittivity ( ϵ′ ), dielectric loss tangent (tan δ ), complex electric modulus ( M* ), and complex impedance ( Z* ) as a function of frequency were reported. The DC conductivity of PVA was increased with the addition of glycerol and starch. The permittivity of PVA films and PVA/starch/graphene nanocomposites showed a strong frequency‐dependent behaviour in a low frequency zone. The addition of graphene to the PVA/starch blend reduced the area under the semicircles of the Nyquist plot.
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