@misc{SchoenemannKocAldredetal.2019, author = {Sch{\"o}nemann, Eric and Koc, Julian and Aldred, Nick and Clare, Anthony S. and Laschewsky, Andr{\´e} and Rosenhahn, Axel and Wischerhoff, Erik}, title = {Synthesis of novel sulfobetaine polymers with differing dipole orientations in their side chains, and their effects on the antifouling properties}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1}, issn = {1866-8372}, doi = {10.25932/publishup-52482}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-524820}, pages = {9}, year = {2019}, abstract = {The impact of the orientation of zwitterionic groups, with respect to the polymer backbone, on the antifouling performance of thin hydrogel films made of polyzwitterions is explored. In an extension of the recent discussion about differences in the behavior of polymeric phosphatidylcholines and choline phosphates, a quasi-isomeric set of three poly(sulfobetaine methacrylate)s is designed for this purpose. The design is based on the established monomer 3-[N-2-(methacryloyloxy)ethyl-N,N-dimethyl]ammonio-propane-1-sulfonate and two novel sulfobetaine methacrylates, in which the positions of the cationic and the ionic groups relative to the polymerizable group, and thus also to the polymer backbone, are altered. The effect of the varied segmental dipole orientation on their water solubility, wetting behavior by water, and fouling resistance is compared. As model systems, the adsorption of the model proteins bovine serum albumin (BSA), fibrinogen, and lysozyme onto films of the various polyzwitterion surfaces is studied, as well as the settlement of a diatom (Navicula perminuta) and barnacle cyprids (Balanus improvisus) as representatives of typical marine fouling communities. The results demonstrate the important role of the zwitterionic group's orientation on the polymer behavior and fouling resistance}, language = {en} } @misc{CommingesFrascaSuetterlinetal.2014, author = {Comminges, Cl{\´e}ment and Frasca, Stefano and S{\"u}tterlin, Martin and Wischerhoff, Erik and Laschewsky, Andr{\´e} and Wollenberger, Ursula}, title = {Surface modification with thermoresponsive polymer brushes for a switchable electrochemical sensor}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-99471}, year = {2014}, abstract = {Elaboration of switchable surfaces represents an interesting way for the development of a new generation of electrochemical sensors. In this paper, a method for growing thermoresponsive polymer brushes from a gold surface pre-modified with polyethyleneimine (PEI), subsequent layer-by-layer polyelectrolyte assembly and adsorption of a charged macroinitiator is described. We propose an easy method for monitoring the coil-to-globule phase transition of the polymer brush using an electrochemical quartz crystal microbalance with dissipation (E-QCM-D). The surface of these polymer modified electrodes shows reversible switching from the swollen to the collapsed state with temperature. As demonstrated from E-QCM-D measurements using an original signal processing method, the switch is operating in three reversible steps related to different interfacial viscosities. Moreover, it is shown that the one electron oxidation of ferrocene carboxylic acid is dramatically affected by the change from the swollen to the collapsed state of the polymer brush, showing a spectacular 86\% decrease of the charge transfer resistance between the two states.}, language = {en} } @misc{SchoenemannLaschewskyWischerhoffetal.2019, author = {Sch{\"o}nemann, Eric and Laschewsky, Andr{\´e} and Wischerhoff, Erik and Koc, Julian and Rosenhahn, Axel}, title = {Surface modification by polyzwitterions of the sulfabetaine-type, and their resistance to biofouling}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {919}, issn = {1866-8372}, doi = {10.25932/publishup-44200}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-442007}, pages = {35}, year = {2019}, abstract = {Films of zwitterionic polymers are increasingly explored for conferring fouling resistance to materials. Yet, the structural diversity of polyzwitterions is rather limited so far, and clear structure-property relationships are missing. Therefore, we synthesized a series of new polyzwitterions combining ammonium and sulfate groups in their betaine moieties, so-called poly(sulfabetaine)s. Their chemical structures were varied systematically, the monomers carrying methacrylate, methacrylamide, or styrene moieties as polymerizable groups. High molar mass homopolymers were obtained by free radical polymerization. Although their solubilities in most solvents were very low, brine and lower fluorinated alcohols were effective solvents in most cases. A set of sulfabetaine copolymers containing about 1 mol \% (based on the repeat units) of reactive benzophenone methacrylate was prepared, spin-coated onto solid substrates, and photo-cured. The resistance of these films against the nonspecific adsorption by two model proteins (bovine serum albumin—BSA, fibrinogen) was explored, and directly compared with a set of references. The various polyzwitterions reduced protein adsorption strongly compared to films of poly(n-butyl methacrylate) that were used as a negative control. The poly(sulfabetaine)s showed generally even somewhat higher anti-fouling activity than their poly(sulfobetaine) analogues, though detailed efficacies depended on the individual polymer-protein pairs. Best samples approach the excellent performance of a poly(oligo(ethylene oxide) methacrylate) reference.}, language = {en} } @misc{HildebrandLaschewskyWischerhoff2015, author = {Hildebrand, Viet and Laschewsky, Andr{\´e} and Wischerhoff, Erik}, title = {Modulating the solubility of zwitterionic poly((3- methacrylamidopropyl)ammonioalkane sulfonate)s in water and aqueous salt solutions via the spacer group separating the cationic and the anionic moieties}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-103040}, pages = {731 -- 740}, year = {2015}, abstract = {Complementary to the well-established zwitterionic monomer 3-((3-methacrylamidopropyl)dimethylammonio) propane-1-sulfonate (SPP), the closely related monomers 2-hydroxy-3-((3-methacrylamidopropyl) dimethylammonio)propane-1-sulfonate (SHPP) and 4-((3-methacrylamidopropyl)dimethylammonio)-butane-1-sulfonate (SBP) were synthesised and polymerised by reversible addition-fragmentation chain transfer (RAFT) polymerisation, using a fluorophore labeled RAFT agent. The polyzwitterions of systematically varied molar masses were characterised with respect to their solubility in water and aqueous salt solutions. Both poly(sulfobetaine)s show thermoresponsive behaviour in water, exhibiting phase separation at low temperatures and upper critical solution temperatures (UCST). For both polySHPP and polySBP, cloud points depend notably on the molar mass, and are much higher in D2O than in H2O. Also, the cloud points are effectively modulated by the addition of salts. The individual effects can be in parts correlated to the Hofmeister series for the anions studied. Still, they depend in a complex way on the concentration and the nature of the added electrolytes, on the one hand, and on the detailed nature of the spacer group separating the anionic and the cationic charges of the betaine moiety, on the other hand. As anticipated, the cloud points of polySBP are much higher than the ones of the analogous polySPP of identical molar mass. Surprisingly, the cloud points of polySHPP are also somewhat higher than the ones of their polySPP analogues, despite the additional hydrophilic hydroxyl group present in the spacer separating the ammonium and the sulfonate moieties. These findings point to a complicated interplay of the various hydrophilic components in polyzwitterions with respect to their overall hydrophilicity. Thus, the spacer group in the betaine moiety proves to be an effective additional molecular design parameter, apparently small variations of which strongly influence the phase behaviour of the polyzwitterions in specific aqueous environments.}, language = {en} } @misc{EnzenbergLaschewskyBoeffeletal.2017, author = {Enzenberg, Anne and Laschewsky, Andr{\´e} and Boeffel, Christine and Wischerhoff, Erik}, title = {Influence of the near molecular vicinity on the temperature regulated fluorescence response of poly(N-vinylcaprolactam)}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-400634}, pages = {21}, year = {2017}, abstract = {A series of new fluorescent dye bearing monomers, including glycomonomers, based on maleamide and maleic esteramide was synthesized. The dye monomers were incorporated by radical copolymerization into thermo-responsive poly(N-vinyl-caprolactam) that displays a lower critical solution temperature (LCST) in aqueous solution. The effects of the local molecular environment on the polymers' luminescence, in particular on the fluorescence intensity and the extent of solvatochromism, were investigated below as well as above the phase transition. By attaching substituents of varying size and polarity in the close vicinity of the fluorophore, and by varying the spacer groups connecting the dyes to the polymer backbone, we explored the underlying structure-property relationships, in order to establish rules for successful sensor designs, e.g., for molecular thermometers. Most importantly, spacer groups of sufficient length separating the fluorophore from the polymer backbone proved to be crucial for obtaining pronounced temperature regulated fluorescence responses.}, language = {en} } @misc{InalKoelschSellrieetal.2013, author = {Inal, Sahika and K{\"o}lsch, Jonas D. and Sellrie, Frank and Schenk, J{\"o}rg A. and Wischerhoff, Erik and Laschewsky, Andr{\´e} and Neher, Dieter}, title = {A water soluble fluorescent polymer as a dual colour sensor for temperature and a specific protein}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-95336}, pages = {6373 -- 6381}, year = {2013}, abstract = {We present two thermoresponsive water soluble copolymers prepared via free radical statistical copolymerization of N-isopropylacrylamide (NIPAm) and of oligo(ethylene glycol) methacrylates (OEGMAs), respectively, with a solvatochromic 7-(diethylamino)-3-carboxy-coumarin (DEAC)- functionalized monomer. In aqueous solutions, the NIPAm-based copolymer exhibits characteristic changes in its fluorescence profile in response to a change in solution temperature as well as to the presence of a specific protein, namely an anti-DEAC antibody. This polymer emits only weakly at low temperatures, but exhibits a marked fluorescence enhancement accompanied by a change in its emission colour when heated above its cloud point. Such drastic changes in the fluorescence and absorbance spectra are observed also upon injection of the anti-DEAC antibody, attributed to the specific binding of the antibody to DEAC moieties. Importantly, protein binding occurs exclusively when the polymer is in the well hydrated state below the cloud point, enabling a temperature control on the molecular recognition event. On the other hand, heating of the polymer-antibody complexes releases a fraction of the bound antibody. In the presence of the DEAC-functionalized monomer in this mixture, the released antibody competitively binds to the monomer and the antibody-free chains of the polymer undergo a more effective collapse and inter-aggregation. In contrast, the emission properties of the OEGMA-based analogous copolymer are rather insensitive to the thermally induced phase transition or to antibody binding. These opposite behaviours underline the need for a carefully tailored molecular design of responsive polymers aimed at specific applications, such as biosensing.}, language = {en} }