Effects of inorganic salts on the spectral behavior of poly(N-vinyl-2-pyrrolidone) in aqueous solutions


Guner A.

JOURNAL OF APPLIED POLYMER SCIENCE, vol.75, no.11, pp.1434-1439, 2000 (Journal Indexed in SCI) identifier

  • Publication Type: Article / Article
  • Volume: 75 Issue: 11
  • Publication Date: 2000
  • Title of Journal : JOURNAL OF APPLIED POLYMER SCIENCE
  • Page Numbers: pp.1434-1439

Abstract

Electronic spectral behavior of poly(N-vinyl-2-pyrrolidone) (PVP) was determined in aqueous solutions including a variety of inorganic salts (phosphates, mono- and dihydrogen phosphates, sulfates, chlorides, nitrates, bisulfites, and persulfates) for several concentrations. The n --> pi* excitations are shifted to longer wavelengths depending on the nature and the concentration of salt. The resulting dependence of lambda(max) on the molar concentration can be expressed to show the increasing effect of anionic and cationic species in bathochromic shift. The increasing order of effectiveness of anions in shifting the lambda(max) is S2O8 (=) > S2O5 > (=) > PO43- > HPO42- > SO42- > H2PO42- > Cl-. The order for the cation is as Na+ approximate to K+ approximate to NH4+ in the 0.1-0.6M concentration range and Na+ approximate to K+ > NH4+ in > 0.6M aqueous solutions. The changes observed in lambda(max) by the salt were correlated with the changes occurring in the structure of water and the polymer-solvent interactions. (C) 2000 John Wiley & Sons, Inc.