Studies on fluorescent PVA + PVP + MPDMAPP composite films

Abstract

Polymer blends along with 1-(4-methylphenyl)-3-(4-N,N, dimethyl amino phenyl)-2-propen-1-one (MPDMAPP) NLO-chromophore-doped composite films were prepared by solvent casting method using DMF. The optical properties were studied using UV-visible, refractive index, steady state fluorescence, and fluorescence microscopic imaging techniques. The UV-vis absorption spectra showed three absorption bands and were assigned to localized n ? p*, n ? p* inter band, and p ? p* transition of charge transfer groups. The observed changes in the absorption peak, edges, and intensity with dopant concentration are understood based on charge transfer complex (CTC) formation. The refractive indices of the composite films varied from 1.4937-1.5398 for red and 1.5165-1.5516 for green light respectively. The steady state fluorescence data showed both emission peak wavelengths and intensity changes with MPDMAPP doping level in blend. The fluorescence anisotropy (r) variations in the composite films indicate the suppressed molecular motion of MPDMAPP in the solid composite film. The fluorescence microscopic image of these composite films showed that the films are photochromatic in nature. These modified properties are thought to be due to the charge transfer upon excitation from the donor to the acceptor connected through benzene ring and CTC formation. POLYM. ENG. SCI.,

Preparation, characterization, electrical and antibacterial properties of sericin/poly(vinyl alcohol)/poly(vinyl pyrrolidone) composites

“…In this context, the blending of poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP) leads to a water-soluble and biodegradable polymer with improved mechanical properties. [6][7][8] Sericin is a natural, macromolecular water-soluble protein derived from silk cocoons. The silk fibers are composed of a protein fibroin with sericin surrounding it, and the removal of sericin from silk fiber is accomplished by a process called degumming.…”

Investigation of third‐order nonlinear optical properties of pyrazoline‐doped polyvinyl alcohol films

“…A few new peaks in the range 426–495 have appeared for different concentrations. These changes may be attributed to the hydrogen bonding between OH groups of PVA with different groups of PDAP and formation of CTC [ 20] as seen in FTIR results. The formation of CTC results in the creation of new molecular dipoles or reorientation of the already existing dipoles.…”

“…Generally, the molecules having π‐bonds, upon excitation with polarized light, undergo successive isomerization and change their orientation. Hence, the increase in fluorescence intensity may be thought to be due to dipole–dipole interactions because of aggregation of chromophores as with the case of chalcone‐doped PVA [20]. And also the observed stokes‐shifted emission is due to different extents of stabilization of the photo generated charge species in the excited state.…”

Positron annihilation and other experimental studies on polycarbonate/MPDMAPP nanocomposite

“…In our earlier article, we have reported PALS results of MPDMAPP chalcone chromophore doped PVA and showed that the formation of CTCs alter the microstructural properties of PVA . In another article, we have also reported about the photochromic nature in fluorescence emission properties of MPDMAPP doped PVA/PVP blend due to intermolecular hydrogen bonding and formation of CTCs. The UV–Vis absorption spectroscopy is an important tool to study the optical transitions and to obtain information about the optical band gap in polymeric materials.…”

“…The chalcone derivatives are noticeable materials for their excellent blue light transmittance. Polymers embedded with chalcone derivatives normally show good optical properties, fluorescence polarization, color change, fluorescent complex formation, and photochromism …”