Formation of poly(vinyl alcohol)-iodine complexes in solution

Abstract

The effect of the dissolved state of poly(vinyl alcohol) (PVA) molecules in water on the color development due to PVA–iodine complexes was investigated at each given PVA and iodine concentration using two kinds of syndiotactic‐rich PVA (S‐PVA) which are unstable in water because of the formation of intermolecular hydrogen bonds and form the complex easily. In the reaction mixtures prepared by mixing PVA solutions and an iodine solution, the color development was constant and independent of standing time of the PVA solution before the addition of iodine up to a certain time, after which it decreased with the standing time. The color development obtained with use of the PVA solution allowed to stand for a fixed time was higher for S‐PVA with a lower s‐(diad)%. In the case of the reaction mixture prepared by dissolving PVA in an iodine solution, the color development was higher for S‐PVA with a higher s‐(diad)%. The initial ratio of the I5−/I3− and the rate of decrease in the ratio of I5−/I3− were larger than those in the preceding case. The color development decreased for the PVA with an s‐(diad) % of 58, whereas it increased for the PVA an s‐(diad) % of 61.3 with increasing propanol content, an inhibitor of gelation. From these results, the aggregates of PVA molecules have been assumed to play an important role in forming the complexes. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 1701–1709, 1997

Polymeric Iodophors: Preparation, Properties, and Biomedical Applications

“…Polyiodide chains are presumably incorporated in syndiotactic PVA aggregates to produce complexes ( Fig. 5 ) [ 29 ]. Quantum chemical computations revealed hydrogen interactions between the hydrogen atom of a hydroxyl group of PVA and an iodine ion [ 30 ].…”

“… The aggregate model of PVA–iodine complexes. Reproduced from [ 29 ] with permission from John Wiley and Sons. …”

Polyvinyl alcohol-based polarizers for new displays: molecules, processing and properties

“…Hence, studying the mechanism of PVA-iodine complexes is essential for understanding the optical properties of polarizing films. 7,93 The dichroism of polarizing iodine-containing crystals was first observed by Phelps and Herapath 94 in 1852, who noticed that these crystals exhibited varying brightness and darkness when overlapped under a microscope. In 1927, Herrmann 95 and Staudinger 96 independently synthesized PVA and discovered its blue reaction with iodine.…”

Molecular iodine/polymer complexes

“…Very interesting research, still going on, is the study of the effect of tacticity, molecu lar weight and branching of PVA ( Figure 7B), and of the content of residual acetyl groups on the I 2 PVA complex formation [137][138][139][140][141][142]. The solutions of this complex were deep blue, green, redorange or yellow, depending upon the conditions.…”