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

✍ Scribed by Ali Güner

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 131 KB
• Volume: 75
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/(sici)1097-4628(20000314)75:11<1434::aid-app16>3.0.co;2-n

✦ Synopsis

Electronic spectral behavior of poly(N-vinyl-2-pyrrolidone) (PVP) was determined in aqueous solutions including a variety of inorganic salts (phosphates, monoand dihydrogen phosphates, sulfates, chlorides, nitrates, bisulfites, and persulfates) for several concentrations. The n 3 * excitations are shifted to longer wavelengths depending on the nature and the concentration of salt. The resulting dependence of 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 max is S

The order for the cation is as Na ϩ Ϸ K ϩ Ϸ NH 4 ϩ in the 0.1-0.6M concentration range and Na ϩ Ϸ K ϩ Ͼ NH 4 ϩ in Ͼ 0.6M aqueous solutions. The changes observed in max by the salt were correlated with the changes occurring in the structure of water and the polymer-solvent interactions.