Super-Salt-Resistive Gel Prepared from Poly(4-vinyl phenol)

Abstract

A hydrogel was prepared by cross-linking poly(4-vinyl phenol) with ethylene glycol diglycidyl ether in order to examine the ion-specific swelling behavior. The swelling ratios to various kinds of aqueous salt solutions except for N(CH3)4Cl were almost constant, or the gels remained in a swollen state, up to their saturated concentrations. This unexpected result was ascribed to stabilization of hydrogen-bonding hydrations to the phenol OH proton and to the phenol ring (π electrons) by anions and cations, respectively. The supposed mechanism was supported by ab initio calculations for the corresponding small model systems.

Preparation and salt-resistivity of poly(vinyl alcohol)-4-hydroxyl phthalate hydrogels

“…It was known that the hydrogen bonding hydration (HBH) to acidic proton could be stabilized by anions with strong hydration ability such as SO 4 2-, and the HBH to π-electron (benzene ring) could be stabilized by small cations. 18,19 Therefore, like the case of PVA-T, the stabilization of HBHs to acidic protons of the phenyl -OH and -COOH on substituting group by SO 4 2-and that of HBHs to π-electron by Li + or Na + will certainly scissor the associated hydrogen bonding (HB) between macromolecules, leading to the swelling of hydrogels (Scheme II(b)). However, besides HBH of side groups, the hydrophobic hydration (HPH) of main chain, which is unfavorable for cations and SO 4 2-to stabilize, 24 becomes substantial especially in the higher salt concentration region.…”

“…The swelling behavior of P4VPh and P4VBA suggested that the HBH to the acidic proton is not stabilized by SCN -because of its weak hydration ability. 18,19 Thus, the strong physical crosslinkages such as inter-(intra-)molecular HBs and π-π stacking over-whelmed the salting-in effect of SCN -to the main chain. Similarly, the weak stabilization effects to hydrations of main chain and side groups by Cl -may explain the apparently inert swelling behavior, except for the slight cation specificity.…”

“…[15][16][17] In our previous works on the ionic effects on polymer gel swelling, we discovered that poly(4-vinyl phenol) (P4VPh) and poly(4-vinyl benzoic acid) (P4VBA) gels show unexpected and extraordinary super salt-resistivity in many kinds of salt solutions, including sulfate anion, a typical salting-out agent, up to their saturated concentrations. 18,19 This unique property is ascribed to specific stabilization of HBH to benzene ring (π electron) and acidic proton by cations and anions, respectively.…”

Photochemical Reactions of Poly(4‐vinylphenol) Thin Films

“…[2][3][4][5][6] Recent applications of PVP include its use as a substitute for water resistive wood adhesive, [7] as a gate dielectric insulator in organic field effect transistors, [8,9] and as responsive surface coatings. [10][11][12] We have developed a simple photochemical immobilization technique for the fabrication of polymer thin films on solid substrates. [13][14][15] The method is based on the photochemistry of polymers.…”

“…Possible photochemically induced reactions of PVP: crosslinking (1-6), re-arrangement(7,8), oxidation(9), and chain scission(10,11).…”