Water‐Swollen Hydrogels with Pendant Terthiophenes

Abstract

A chemically cross‐linked and water‐swollen poly(AA3T‐co‐AA) gel having pendant terthiophenes was synthesized by radical copolymerization of [(2,2′:5′,2″‐terthiophen‐5‐yl‐)methyl acrylate] (AA3T) and acrylic acid (AA), and its swelling, dissociation, and doping behaviors were studied. The gel swells in high pH solution, which is associated with the dissociation and, hence, electrostatic repulsion of the AA units, and the pH value at which the swelling starts increases with increasing AA3T composition. The dissociation of the gels is suppressed, presumably due to the incorporation of the hydrophobic AA3T unit, and, once started, the dissociation could be promoted by AA3T in the low pH region. Poly(AA3T‐co‐AA) copolymers and gels can be easily electrochemically and chemically doped. The volume change of the gels is observed during doping/undoping and the maximum volume change reached was about 50%.

When Mesoporous Silica Meets the Alkaline Polyelectrolyte: A Controllable Synthesis of Functional and Hollow Nanostructures with a Porous Shell

“…Chemical doping of P3T‐NaSS and P3T‐PEG gels was carried out using 70% HClO 4 solution as a dopant. When these gels were immersed in 70% HClO 4 solution, both of them changed color from yellow to purple and then black immediately; this was also reported for poly(AA3T‐ co ‐AA) in our previous paper 16. The absorption spectra in Figure 6 showed new bands at λ max 550 and 840 nm along with an absorption around 370 nm for these gels, suggesting changes in the π ‐conjugated structure by doping using HClO 4 solution.…”

Study on Doping Behaviors of Vinyl Hydrogels with Pendant Terthiophenes

“…When these gels were immersed in 70% HClO 4 solution, both of them changed color from yellow to purple and then black immediately; this was also reported for poly(AA3T-co-AA) in our previous paper. [16] The absorption spectra in Figure 6 showed new bands at l max 550 and 840 nm along with an absorption around 370 nm for these gels, suggesting changes in the p-conjugated structure by doping using HClO 4 solution. From these results, we noted that the waterswollen P3T-NaSS gel could easily undergo self-doping in the low pH solution, and both P3T-NaSS and P3T-PEG could be chemically doped by using concentrated HCl or HClO 4 .…”