Debabrata Bhadra
@bhairabgangulycollege.ac.in
Assiatant Professor, Department of Physics
Bhairab Ganguly College, Kolkata-56, West Bengal, India
RESEARCH INTERESTS
Polymer Composites, Ferroelectric Materials, Bionanocomposites, Nanomaterials, Membrane studies, Tissue Engineering
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Biswadeep Chaudhuri, Shrabani Ghosh, Bholanath Mondal, and Debabrata Bhadra
Elsevier BV
Debabrata Bhadra
Wiley
Polyvinyl alcohol (PVA) composites with a conductive filler, graphite powder (GP) were prepared by solution casting process. GP remains well dispersed in the PVA composites as evidenced by the lack of the characteristic graphite reflection in the composites. SEM imaging show smooth fractured surfaces with graphite stacks and obvious debonding from the matrix in the GP/PVA composites. The dielectric dispersion and AC conductivity of the composite system exhibited a strong frequency dependence particularly in the vicinity of percolation threshold (fc ∼ 6 wt% = 2.65 vol%). A 150 times increase of dielectric permittivity and seven orders of magnitude higher conductivity were obtained by adding 2.65 vol% graphite powder in PVA indicating the efficient loading between the graphite and the matrix at percolation threshold which is well above the percolation threshold (fc = 0.41 vol%) for PVA/GOnP composites. Moreover, the dielectric properties were measured at about 30°C and 1 kHz. The values of permittivity and dielectric loss were found to increase with increasing graphite content. The percolative composites exhibit very low dielectric loss and leakage current density. Such GP/PVA flexible composites in tailored form might be important for many printing circuit board and capacitor applications in the age of device miniaturization. POLYM. COMPOS., 00:000–000, 2017. © 2017 Society of Plastics Engineers
Biswadeep Chaudhuri, Debabrata Bhadra, Lorenzo Moroni, and Krishna Pramanik
IOP Publishing
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.
D. Bhadra, S. C. Sarkar, and B. K. Chaudhuri
Royal Society of Chemistry (RSC)
Polymer nanocomposites (PNC) showing improved physical properties are emerging as novel functional materials because of their adaptable physical properties for technological applications.
Debabrata Bhadra, Md. G. Masud, S. K. De, and B. K. Chaudhuri
AIP Publishing
Biswadeep Chaudhuri, Debabrata Bhadra, Bholanath Mondal, and Krishna Pramanik
Elsevier BV
Abstract Biocompatibility of electrospun graphene oxide (GO)–poly (e-caprolactone)-(PCL) composite fibrous scaffolds has been investigated using skeletal muscle cells obtained from human umbilical cord blood (UCB) derived mesenchymal stem cells (CB-hMSCs). Such CB-hMSCs derived human skeletal muscle cells (CB-hSkMCs) adhered, proliferated and formed myotubes when cultured on GO–PCL fibrous scaffold suitable for skeletal muscle tissue engineering applications.
J. Sannigrahi, D. Bhadra, and B. K. Chaudhuri
Wiley
We fabricated an anthracene thin-film transistor (TFT) with an ultrathin layer (∼450 nm) of poly-vinylidene fluoride (PVDF)/graphite oxide nanoplatelets (GOnP) nanocomposite as a gate insulator. We obtained a TFT device with excellent electrical characteristics at low operating voltages (<1 V). The dielectric is a high-e gate insulator with a static dielectric constant of er = 15.6. This device was found to have a field effect mobility of 1.1 cm2 V−1 s, a threshold voltage of 0.34 V, an exceptionally low subthreshold slope (SS) of 380 mV decade−1 and an on/off ratio of 105. The combination of favorable properties opens up the possibility to utilize such TFTs effectively at voltages as low as below 1 V. Such high-e PVDF/GOnP gate dielectric appears to be highly promising candidates for organic nonvolatile memories and sensor field effect transistors (FETs).
Debabrata Bhadra, Md. G. Masud, S. K. De, and B. K. Chaudhuri
AIP Publishing
A two-phase multifunctional La2CoMnO6 (LCMO)/Poly-vinylidene fluoride 0–3 flexible nanocomposite (NCOMP) thick films have been prepared. Interestingly, this NCOMP shows linear increase of magnetoelectric voltage coefficient (MVC) with applied dc magnetic-bias fields up to 5 kOe, exhibiting no sign of hysteresis. For the typical LCMO concentration, fLCMO = 0.15, the maximum MVC measured is 1.45 mV cm−1 Oe−1 (using 50 kHz resonant signal). This low dielectric loss (∼0.12) NCOMP also showed intriguing high magnetodielectric effect (∼10%) around the ferromagnetic transition temperature (Tc ∼ 230 K) with minimal leakage current. Such results make the present nanocomposite significantly important for the development of magnetic field tuned electronic devices.
Biswadeep Chudhuri, D. Bhadra, S. Dash, G. Sardar, K. Pramanik, and B. K. Chaudhuri
American Scientific Publishers
D Bhadra, Md G Masud, S K De, and B K Chaudhuri
IOP Publishing
Flexible magnetoelectric 0?3 composite films formed with high dielectric (?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 (?eff???103) with good ferroelectric behaviour (with P?E loop) at the percolation threshold (fCuO?=?fc???0.25). Dielectric, ferroelectric, magnetic and direct magnetoelectric properties of the composites depend strongly on the CuO filler concentration (fCuO). Interesting low field magnetoelectric response appears with about 5% decrease in ferroelectric polarization in the insulating composite (fCuO?=?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.
Jhuma Sannigrahi, D. Bhadra, Md. G. Masud, and B. K. Chaudhuri
AIP
Magnetic zinc ferrite (ZnFe2O4) nanoparticles (MZFN) and Graphene Oxide (GO) composites were prepared through low temperature reaction process. X-ray Diffraction and transmission electron microscopic studies of the individual's constituents reveal the crystalline nanocomposite nature. Anomalous transport properties with metal like to thermally activated semiconducting transition is observed around 160K for a typical MZFN/GO ratio (1: 0.25) which is explained by considering the formation of percolated GO clusters.
D. Bhadra, J. Sannigrahi, S. K. De, and B. K. Chaudhuri
AIP
Polyvinyl alcohol (PVA) composites with graphite oxide nanoplatelets (GOnP) and pure graphite powder (GP) were prepared via solution casting method. A significant enhancement of electrical conductivity of the GOnP/PVA composites is obtained at low GOnP concentration i.e.; percolation threshold. Interestingly, a much lower percolation threshold (fc =0.41 vol %, the lowest reported value for any graphite oxide-based composites) was obtained for the GOnP/PVA composites compared to the corresponding GP/PVA composites (fc ∼above 6 vol%).
Md Jamal Uddin, J. Sannigrahi, Md G. Masud, D. Bhadra, and B. K. Chaudhuri
Wiley
A new kind of anhydrous, transparent, and flexible potassium dihydrogen phosphate (KH2PO4 or KDP)/polyvinyl alcohol (PVA) composite in the form of film (0.10 mm) has been prepared by solution casting technique. KDP is well dispersed in the polymer matrix as observed from the microstructural studies. Frequency and temperature dependent dielectric properties of the composites have been studied with varying KDP concentrations. The PVA/KDP composite films exhibited extraordinarily high relative permittivity e′ ∼ 430 (80 times higher compared with pure PVA and even higher than KDP) near the percolation threshold (ϕC = 2.5 wt % KDP) with low dielectric losses (∼ 0.15) at 1 kHz and room temperature. Such flexible, low loss and high dielectric permittivity material has enormous importance for application in devices. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Debabrata Bhadra, Md. G. Masud, S. Sarkar, J. Sannigrahi, S. K. De, and B. K. Chaudhuri
Wiley
Debabrata Bhadra, J. Sannigrahi, B. K. Chaudhuri, and H. Sakata
Wiley
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
Debabrata Bhadra, A. Biswas, S. Sarkar, B. K. Chaudhuri, K. F. Tseng, and H. D. Yang
AIP Publishing
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 (eeff∼400 which is 40 times higher than that of pure PVDF) with low loss (∼0.20 at 1 kHz) is observed. The experimental eeff data have been fitted with different theoretical models and found to follow percolation theory successfully. Such a high eeff and low loss flexible dielectric material appears to be suitable for technological applications.