General

In the present communication, an attempt is made to prepare and study the structural, optical, and aging properties of polyvinylchloride (PVC)-polyvinylpyrrolidone (PVP) blend films for their probable applications as biodegradable/biocompatible materials in biomedical and optoelectronics fields. The surface properties such as contact angles and surface free energies of films are measured to investigate the interaction of polymer films with water. These measurements reveal that on increasing the weight percentage concentration of PVP in PVC, the hydrophilicity of the films increases. The surface free energy was found to increase with increasing concentration of PVP in PVC, which indicates that these films tend to adsorb more moisture from the atmosphere and, thereby, will have a tendency to age faster. The Fourier transform infra-red spectroscopy (FTIR) spectra of blend films indicate a significant change in the intermolecular/intramolecular interactions taking place. The UV-visible ...

Present study is carried out to understand the effect of conducting polymer, polypyrrole (PPy) on structural, morphological, thermal and dielectric properties of bio-compatible polymer blend film of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP). The growth of PPy in the matrix of PVA–PVP was analyzed using XRD, FT-IR and SEM studies. The shifting in positions and broadening of XRD diffraction peaks of PVA–PVP-PPy from that of PVA–PVP indicates the structural modification and reduction in the crystallinity of the PVA–PVP due to incorporation of PPy. The SEM studies suggest scattered growth of PPy in PVA–PVP matrix at lower concentration of pyrrole monomer. As the monomer concentration is increased, the uniform and interconnected growth of PPy was observed in SEM micrographs. The TGA thermograms show faster thermal degradation of PVA–PVP- PPy films at lower temperature as compared to PVA–PVP films. The blend films of PVA–PVP- PPy exhibited enhanced values of dielectric const...

In present communication, an attempt is made to prepare and study structural, optical, and electrical properties of biocompatible polyvinylchloride (PVC)-polyvinylpyrrolidone (PVP) blend films taken in ratio of 1:1 doped with conducting polymer Polypyrrole (PPy).The XRD spectra revealed amorphous nature of all the films under investigation. The Fourier transform infra-red spectroscopy (FTIR) study of conducting polymer doped blend films indicate a significant change in the intermolecular/intramolecular interactions taking place. The study on electrical properties of conducting polymer doped blend films show better conduction of current as compared to that of blend film without conducting polymer and dopant concentration dependent electrical conductivity and conduction mechanism. The results of optical study of conducting polymer doped blend films revealed the possibility of band gap modification from wide band gap to small band gap with suitable doping concentration. These biocompat...

Electromagnetic interference is a cause of concern when emitted electromagnetic fields interfere with operation of other electronic equipments. Given rapid development in commercial, military, scientific electronic devices and communication instruments operating in microwave frequency range (GHz), there has been an increased interest in development of such materials that could shield against electromagnetic radiation to protect interference. Conducting polymers can be used as microwave absorbing materials with or without fillers. In the present paper we report the complex permittivity measurements of pure PVC and PVC doped with varying concentrations of PPy films at microwave frequency of 9.37 GHz ( X-band) using microwave bench at room temperature. Further the microwave absorption properties of these films of various thicknesses have been investigated. The maximum absorption coefficient of 118 m was obtained for film of average thickness 850 μm and with 16% concentration of PPy in ...

In the present communication, an attempt has been made to prepare and study surface and dielectric properties of polyvinylchloride-polyvinylpyrrolidone blend films. Surface properties such as water absorption, contact angle, surface free energy of the films have been measured to investigate the interaction of blend films with water. These measurements reveal that on increasing the weight percentage concentration of polyvinylpyrrolidone in polyvinylchloride, hydrophilicity of the films increases. The surface free energy increases with increasing concentration of polyvinylpyrrolidone in polyvinylchloride, which indicates that these films tend to adsorb more moisture and dust particles from atmosphere thereby affecting its ageing and rendering it degradability. Further the dielectric properties in the low frequency range (1 kHz – 2 MHz) have been studied. The results show that the dielectric constant, loss tangent and ac conductivity of blend films increase as the weight percentage con...

A comparative study is carried out to observe the effect of dispersing Zinc Oxide (ZnO) nanoparticles in two different host matrices of Polyvinylalcohol (PVA)—Polyvinylpyrrolidone (PVP)—Polyvinylalcohol (PVA)—Carboymethyl Cellulose (CMC) on their structural, optical and electrical properties. The concentration of ZnO in the blend films was kept low. The XRD diffractogram of both the polymer nanocomposite films (PNCs) exhibited characteristic peaks of ZnO confirming the dispersion of nanoparticles in blended films. The SEM micrographs of these PNC films had shown uniform dispersion of ZnO nanoparticles in both matrices. The analysis of optical and electrical properties indicates appreciable modification in these properties on inclusion of small amount of ZnO in both the matrices. ZnO dispersed PVA–CMC film shows enhanced absorption in UV region with decreased band gap and higher σdc values as compared to ZnO dispersed PVA–PVP film suggesting PVA–CMC–ZnO film to be a promising material in the area of green electronics and optoelectronics.

The refractive index ( n ), dispersion and optical conductivity (σ opt ) of undoped and PPy doped PVC films have been studied. The PPy doped PVC films   are prepared by solution cast technique with various concentrations of PPy (6% to 20%) in PVC. The optical absorption spectra of these films have been recorded in the wavelength range 400-900 nm at room temperature. Optical parameters such as refractive index ( n ), extinction coefficient ( k ), real (eʹ) and imaginary (eʹʹ) parts of complex permittivity, optical conductivity (σ opt ) and infinitely high frequency dielectric constant (e ∞ ) have been evaluated. It is seen that the optical properties of PVC have been affected on doping it with PPy. The average refractive index ( n ), infinitely high frequency dielectric constant (e ∞ ) and optical conductivity (σ opt ) of the samples exhibit a nonlinear compositional dependence as observed in many amorphous materials.

The aim of the present work is concerned with the study of the optical behavior of Polypyrrole doped Polyvinylchloride films at different concentrations of Polypyrrole. .The samples are casted as films. The films were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM). The optical properties of these films are evaluated using UV-VIS spectrophotometer. The XRD spectra showed the amorphous nature of the films. SEM studies revealed a uniform granular structure of PPy. From UV- VIS spectra optical band gap of the films has been calculated using the Tauc's relation and variations in the values of optical band gap with the variation of percentage concentration of PPy in PVC and have been found to vary from 2.3 to 4.1 ev. The band tail width of localized states has been calculated using Urbach's relation.

In the present communication, microwave absorbing property in the frequency range of 12.4–18 GHz and in vitro biocompatibility studies of light weight, flexible, biocompatible, and environment friendly polymer blend films of polyvinylchloride (PVC)-polyvinylpyrrolidone (PVP) (taken in ratio 1:1) and doped with various percentage weight concentration of polypyrrole (PPy) are reported. Addition of PPy in the PVC-PVP matrix exhibited a synergetic effect in improving microwave absorbing property. PVC-PVP blend film with 40 and 50% concentrations of PPy were seen to absorb microwaves of the order of 28–50 dB in ku band of microwave region indicating that this composition can suitably find application as microwave absorbing material. In vitro biocompatibility skin irritation study of PVC-PVP (taken in ratio 1:1) with 50% weight concentration of PPy indicated that the prepared film did not have any irritation upon administration and hence is safe for topical application. Moreover, the bloo...