Recently graphene and graphene based composites are emerging as better materials to fabricate scaffolds. Addition of graphene oxide (GO) nanoplatelets (GOnPs) in bioactive polymers was found to enhance its conductivity (σ) and, dielectric permittivity (ϵ) along with biocompatibility. In this paper, human cord blood derived mesenchymal stem cells (CB-hMSCs) were differentiated to skeletal muscle cells (hSkMCs) on spin coated thin GO sheets composed of GOnPs and on electrospun fibrous meshes of GO-PCL (poly-caprolactone) composite. Both substrates exhibited excellent myoblast differentiations and promoted self-alignedmyotubesformation similar to natural orientation. σ, ϵ, microstructural and vibration spectroscopic studies were carried out for the characterizations of GO sheet and the composite scaffolds. Significantly enhanced values of both σ and ϵ of the GO-PCL composite were considered to provide favourable cues for the formation of superior multinucleated myotubes on the electrospun meshes compared to those on thin GO sheets. The present results demonstrated that both substrates might be used as potential candidates for CB-hMSCs differentiation and proliferation for human skeletal muscle tissue regeneration.

Graphite oxide nanoplatelets (GOnP) were prepared using standard method and used to make GOnP‐polyvinyl alcohol (PVA) composites by using solution cast technique. Significant enhancement of electrical conductivity and dielectric permittivity of the GOnP/PVA composites are observed at low GOnP concentration (fGOnP = fc∼0.41 vol%) which is the percolation threshold value estimated from the concentration dependent transport and dielectric data. Nearly 300 times increase in dielectric permittivity (compared with that of PVA) is observed in the GOnP/PVA composite around fc. We notice interesting metal‐insulator like transition (a sudden increase in resistivity) from the temperature dependent resistivity data in the pure GOnP sample around TMI ∼ 275 K which is shifted to 300 K in the GOnP/PVA composite for fc = 0.41 vol%, indicating drastic change of sp3/sp2 ratio around respective TMI. The present graphite‐based composite material might be processed for different applications. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers

A novel two-phase polymer nanocomposite film comprising of polyvinylidene fluoride (PVDF) and nanocrystalline ($90 nm) semiconducting multiferroic BiFeO 3 (BFO) have been fabricated by hot-molding technique. Such flexible thick nanocomposite films, semicrystalline in nature, exhibited extraordinarily high effective dielectric permittivity e eff $ 10 3 (compared with that of pure PVDF) near the low percolation threshold (f c ¼ 0.12) at room temperature (RT) and the films also possessed low dielectric loss ($0.18). The polarizationelectric field (P-E) hysteresis loops are displayed at RT, which indicate ferroelectric like behavior of PVDF still persists in the percolative nanocomposite. There is also large increase of remanent polarization of BFO in the composite indicating improvement of the multiferroic behavior of BFO embedded in the PVDF polymer. The sample also indicates good fatigue endurance. Formation of microcapacitors and percolative behavior are correlated to explain the obtained results based on the special geometry of the BFO nanofillers. V C 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 50: 572-579, 2012

Homogeneous thick film (∼0.10 mm) of high dielectric K0.05Ti0.02Ni0.93O; abbreviated as KTNO/polyvinylidene fluoride (PVDF) composite has been prepared by hot-molding technique. The frequency and temperature dependent dielectric behavior of this composite has been studied by varying the KTNO volume fraction (fKTNO). Near the percolation threshold (fKTNO=0.40), a large enhancement of effective dielectric permittivity (εeff∼400 which is 40 times higher than that of pure PVDF) with low loss (∼0.20 at 1 kHz) is observed. The experimental εeff data have been fitted with different theoretical models and found to follow percolation theory successfully. Such a high εeff and low loss flexible dielectric material appears to be suitable for technological applications.

Flexible magnetoelectric 0–3 composite films formed with high dielectric (ε r ∼ 104) CuO microparticles in a polyvinylidene fluoride (PVDF) polymer matrix showed multifunctional properties. The films prepared by the hot-moulding technique exhibit low-loss high relative permittivity (ε eff ∼ 103) with good ferroelectric behaviour (with P–E loop) at the percolation threshold (f CuO = f c ∼ 0.25). Dielectric, ferroelectric, magnetic and direct magnetoelectric properties of the composites depend strongly on the CuO filler concentration (f CuO). Interesting low field magnetoelectric response appears with about 5% decrease in ferroelectric polarization in the insulating composite (f CuO = 0.20) along with 7.5% increase in the magnetodielectric coefficient under a magnetic field of 6 kG in the semiconducting percolative composite at room temperature. At this field, a maximum magnetoelectric voltage coefficient of 1.45 mV cm−1 Oe−1 was obtained. Even though the CuO sample is paramagnetic at ambient temperature, this typical composite film exhibits weakly ferromagnetic (with M–H loop) behaviour indicating multiferroic character. Our result represents an important step towards practical device applications using the high dielectric and magnetoelectric effects.