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End date: 2023 × Start date: 2020 × DDC: 540 × Type: article × Subject: microgels × WGL Institute: DWI ×

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    Tailoring the Cavity of Hollow Polyelectrolyte Microgels
    (Weinheim : Wiley-VCH, 2020) Wypysek, Sarah K.; Scotti, Andrea; Alziyadi, Mohammed O.; Potemkin, Igor I.; Denton, Alan R.; Richtering, Walter
    The authors demonstrate how the size and structure of the cavity of hollow charged microgels may be controlled by varying pH and ionic strength. Hollow charged microgels based on N-isopropylacrylamide with ionizable co-monomers (itaconic acid) combine advanced structure with enhanced responsiveness to external stimuli. Structural advantages accrue from the increased surface area provided by the extra internal surface. Extreme sensitivity to pH and ionic strength due to ionizable moieties in the polymer network differentiates these soft colloidal particles from their uncharged counterparts, which sustain a hollow structure only at cross-link densities sufficiently high that stimuli sensitivity is reduced. Using small-angle neutron and light scattering, increased swelling of the network in the charged state accompanied by an expanded internal cavity is observed. Upon addition of salt, the external fuzziness of the microgel surface diminishes while the internal fuzziness grows. These structural changes are interpreted via Poisson–Boltzmann theory in the cell model. © 2019 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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    Zwitterionic Nanogels and Microgels: An Overview on Their Synthesis and Applications
    (Weinheim : Wiley-VCH, 2021) Saha, Pabitra; Ganguly, Ritabrata; Li, Xin; Das, Rohan; Singha, Nikhil K.; Pich, Andrij
    Zwitterionic polymers by virtue of their unique chemical and physical attributes have attracted researchers in recent years. The simultaneous presence of positive and negative charges in the same repeat unit renders them of various interesting properties such as superhydrophilicity, which has significantly broadened their scope for being used in different applications. Among polyzwitterions of different architectures, micro- and/or nano-gels have started receiving attention only until recently. These 3D cross-linked colloidal structures show peculiar characteristics in context to their solution properties, which are attributable either to the comonomers present or the presence of different electrolytes and biological specimens. In this review, a concise yet detailed account is provided of the different synthetic techniques and application domains of zwitterion-based micro- and/or nanogels that have been explored in recent years. Here, the focus is kept solely on the “polybetaines,” which have garnered maximum research interest and remain the extensively studied polyzwitterions in literature. While their vast application potential in the biomedical sector is being detailed here, some other areas of scope such as using them as microreactors for the synthesis of metal nanoparticles or making smart membranes for water-treatment are discussed in this minireview as well.