@article { ISI:000230531100013, title = {Poly(acrylonitrile) ultrafiltration membranes. I. polymer-salt-solvent interactions}, journal = {Journal of Polymer Science Part B: Polymer Physics}, volume = {43}, number = {15}, year = {2005}, month = {AUG}, pages = {2061-2073}, publisher = {JOHN WILEY \& SONS INC}, type = {Article}, address = {111 RIVER ST, HOBOKEN, NJ 07030 USA}, abstract = {

Fourier transform infrared spectroscopy was used to study the interactions among LiCl, ZnCl2, and AlCl3 with NN-dimethylformamide (DMF) and poly (acrylonitrile) (PAN). It was observed that all three salts complex with DMF as well as PAN. The strength of the cation interaction with the \> C=O oxygen of DMF was found to be higher than that with the -CN group of PAN. The \> C=O stretching frequency of DMF with ZnCl2 was red shifted, indicating stronger complex formation compared with other two cations. With the addition of salt, the salt-DMF pseudo solvent was found to become a 0 solvent for PAN compared with neat DMF. This change in PAN solvation power was primarily the result of DMF-salt complexation. As a result of the complexation, Mark-Houwink constant a, was found to reduce from 0.75 (for pure DMF) to similar to 0.6 for DMF-salt solvents, indicating decreased PAN chain expansion. Comparison of intrinsic viscosity [n] values indicated that addition of salts to PAN-DMF solutions resulted in: (i) decrease in the DMF solvation. power, which causes less expanded polymer coils, and (ii) increased interpolymer chain entanglements via salt-promoted chain association. (c) 2005 Wiley Periodicals, Inc.

}, keywords = {activation energy viscosity, Additives, FT-IR, Poly(acrylonitrile), solution properties}, issn = {0887-6266}, doi = {10.1002/polb.20493}, author = {Phadke, M. A. and Musale, D. A. and Kulkarni, Sudhir S. and Karode, Sandeep K.} } @article { ISI:000265699700015, title = {Control of molecular aggregation in symmetrically substituted pi-conjugated bulky poly(p-phenylenevinylene)s and their copolymers}, journal = {Journal of Polymer Science Part A-Polymer Chemistry}, volume = {47}, number = {10}, year = {2009}, month = {MAY}, pages = {2631-2646}, publisher = {JOHN WILEY \& SONS INC}, address = {111 RIVER ST, HOBOKEN, NJ 07030 USA}, abstract = {

A new series of symmetrically substituted bulky PPV-copolymers based on poly(bis-2,5-(2-ethylhexyloxy)-1,4-phenylenevinylene) (BEH-PPV) bearing tricyclodecane (TCD) pendants were synthesized to study the effect of chain aggregation in the pi-conjugated polymer backbone. The composition of the copolymers was varied up to 100 mol \% and the structures of the copolymer were confirmed by NMR and FTIR. The molecular weights of the copolymers were obtained as M(w) = 11,500-1,78,800 depending on the TCD-incorporation in BEH-PPV. The origin of the pi-aggregation was investigated using mixture of solvents (polar or nonpolar) or temperature as external stimuli. Absorption, photoluminescence, and time-resolved fluorescence decay techniques were employed as tools to trace molecular aggregation in solution and solid state. The TCD-substituted bulky copolymers showed almost twice the enhancement in photoluminescence compared with that of BEH-PPV Solvent-induced aggregation studies of copolymers revealed the existence of strong molecular aggregation in BEH-PPV compared with that of bulky copolymers. Variable temperature studies further evidence for the reversibility of molecular aggregation on beating/cooling cycles and showed isosbetic points with respect to free and aggregated polymer chains. Time-resolved fluorescent studies confirmed the existence of free and aggregated pi-conjugated species with a life time of 0.1 to 1.0 ns. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2631-2646, 2009

}, keywords = {conjugated polymers, fluorescence, poly(p-phenylenevinylene), solution properties, Structure-property relationship}, issn = {0887-624X}, doi = {10.1002/pola.23348}, author = {Resmi, R. and Amrutha, S. R. and Jayakannan, M.} } @article { ISI:000287163600004, title = {Synthesis and drug-delivery behavior of chitosan-functionalized graphene oxide hybrid nanosheets}, journal = {Macromolecular Materials and Engineering}, volume = {296}, number = {2}, year = {2011}, month = {FEB}, pages = {131-140}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

Chitosan-functionalized graphene oxides (FGOCs) were successfully synthesized. FGOCs were found to significantly improve the solubility of the GO in aqueous acidic media. The presence of organic groups was confirmed by means of XPS and TGA. Restoration of the sp(2) carbon network and exfoliation of graphene sheets were confirmed by Raman spectroscopy, UV-visible spectroscopy and WAXD. The SEM and AFM investigations of the resultant FGOCs showed that most of the graphene sheets were individual and few were layered. Controlled release behavior of Ibuprofen and 5-fluorouracil was then investigated. We found that FGOCs are a promising new material for biological and medical applications.

}, keywords = {Biocompatibility, Chitosan, drug delivery systems, functionalization of polymers, solution properties}, issn = {1438-7492}, doi = {10.1002/mame.201000307}, author = {Rana, Vijay Kumar and Choi, Myeon-Cheon and Kong, Jin-Yeon and Kim, Gwang Yeon and Kim, Mi Ju and Kim, Sun-Hee and Mishra, Satyendra and Singh, Raj Pal and Ha, Chang-Sik} }