Electrocontrolled Swelling and Water Uptake of a Three‐Dimensional Conducting Polypyrrole Hydrogel

Abstract

Polypyrrole 3D hydrosponges of tubular structure were synthesized and electrochemically characterized. The Fourier transform infrared attenuated total reflection (FTIR‐ATR) spectroscopy technique was employed to study the water uptake of the hydrosponges under different conditions. This technique presents several advantages over conventional swelling measurements due to its specificity that allows analyzing the kinetics of water uptake at the molecular level. In combination with mathematical modeling, FTIR‐ATR spectroscopy also enables the calculation of the water diffusion coefficients in the hydrogels. The experimental setup also allows electroswelling of the hydrosponges to be studied. The results presented herein are complementary to those obtained with the electrochemical quartz crystal microbalance with dissipation (EQCM‐D) technique and make it possible to determine the actual role played by water in the ionic exchange occurring in conducting polymers during their redox processes. Whereas EQCM‐D shows the whole mass change in the film provoked by injection/ejection of ions and solvent molecules, FTIR‐ATR spectroscopy follows water flux only, which thus allows separation of the solvent contribution.

Cargo shuttling by electrochemical switching of core–shell microgels obtained by a facile one-shot polymerization

“…When now favorably combining different stimuli-sensitive moieties into one microgel,24 the core–shell architecture offers some advantages. This is also seen when considering the diverse and widespread applicability of core–shell particles consisting of inorganic cores and organic shells and vice versa ,68–71 combining more than one functional property. These entities attracted great interest with focus on coating, electronics, biomedical applications, optics, catalysis, separation and diagnostics 70,71.…”

Drug release kinetics of pH‐responsive microgels of different glass‐transition temperatures

“…In addition, it is possible to develop responsive gels, whose swelling characteristics and transitions can be manipulated by pH. One of the possible methods to control the pH responsive properties of the gels is to introduce hydrophobic segments that serve as physical crosslinks by copolymerizing a hydrophilic monomer, such as acrylic acid with hydrophobic alkyl acrylate monomer . Here, the hydrophobic segments will aggregate at pH condition when the MG is uncharged.…”

“…Here, the hydrophobic segments will aggregate at pH condition when the MG is uncharged. In addition, the introduction of hydrophobic microdomains to reduce the brittle nature of the hydrogels also interferes with the network swelling induced by ionization …”

“…The most studied ionic polymers are poly(acrylic acid) (PAA), poly(methacrylic acid) (PMAA), poly(N,N‐dimethylaminoethyl methacrylate) (PDMAEMA), poly(2‐diethylaminoethyl methacrylate) (PDEAEMA), albumin, gelatin, and chitosan . However, the overwhelming majority of hydrogel‐based research used small molecules (monomers and crosslinkers) to construct the gel structure, in contrasts to the approach used in this study involving MG particles .…”

A Sponge‐Like 3D‐PPy Monolithic Material for Reversible Adsorption of Radioactive Iodine

“…The polypyrrole, as representative of the conjugated polymers, was first reported by Dall Olio in 1968 and widely used as adsorbents, catalysts, electrochemical devices, and coatings . Taking advantages of ease fabrication, relative low production cost and especially its conjugated structure, polypyrrole should be potential candidate for removal of radioactive iodine.…”