@article{MaiWolskiPuciulMalinowskaetal.2018, author = {Mai, Tobias and Wolski, Karol and Puciul-Malinowska, Agnieszka and Kopyshev, Alexey and Gr{\"a}f, Ralph and Bruns, Michael and Zapotoczny, Szczepan and Taubert, Andreas}, title = {Anionic polymer brushes for biomimetic calcium phosphate mineralization}, series = {Polymers}, volume = {10}, journal = {Polymers}, number = {10}, publisher = {MDPI}, address = {Basel}, issn = {2073-4360}, doi = {10.3390/polym10101165}, pages = {17}, year = {2018}, abstract = {This article describes the synthesis of anionic polymer brushes and their mineralization with calcium phosphate. The brushes are based on poly(3-sulfopropyl methacrylate potassium salt) providing a highly charged polymer brush surface. Homogeneous brushes with reproducible thicknesses are obtained via surface-initiated atom transfer radical polymerization. Mineralization with doubly concentrated simulated body fluid yields polymer/inorganic hybrid films containing AB-Type carbonated hydroxyapatite (CHAP), a material resembling the inorganic component of bone. Moreover, growth experiments using Dictyostelium discoideum amoebae demonstrate that the mineral-free and the mineral-containing polymer brushes have a good biocompatibility suggesting their use as biocompatible surfaces in implantology or related fields.}, language = {en} } @article{KopyshevLomadzeFeldmannetal.2015, author = {Kopyshev, Alexey and Lomadze, Nino and Feldmann, David and Genzer, Jan and Santer, Svetlana}, title = {Making polymer brush photosensitive with azobenzene containing surfactants}, series = {Polymer : the international journal for the science and technology of polymers}, volume = {79}, journal = {Polymer : the international journal for the science and technology of polymers}, publisher = {Elsevier}, address = {Oxford}, issn = {0032-3861}, doi = {10.1016/j.polymer.2015.09.023}, pages = {65 -- 72}, year = {2015}, abstract = {We report on rendering polyelectrolyte brushes photosensitive by loading them with azobenzene-containing cationic surfactants. Planar poly( methacrylic acid) (PMAA) brushes are synthesized using the "grafting from" free-radical polymerization scheme followed by exposure to a solution of photosensitive surfactants consisting of positively-charged head groups and hydrophobic tails into which azobenzene moieties are inserted. In this study the length of the hydrophobic methylene spacer connecting the azobenzene and the charged head group ranges from 4 to 10 CH2 groups. Under irradiation with UV light, the photo-isomerization of azobenzene integrated into a surfactant results in a change in size, geometry, dipole moment and free volume of the whole molecule. When the brush loaded with photosensitive surfactants is exposed to irradiation with UV interference patterns, the topography of the brush deforms following the distribution of the light intensity, exhibiting surface relief gratings (SRG). Since SRG formation is accompanied by a local rupturing of polymer chains in areas from which the polymer material is receding, most of the polymer material is removed from the surface during treatment with good solvent, leaving behind characteristic patterns of lines or dots. The azobenzene molecules still integrated within the polymer film can be removed by washing the brush with water. The remaining nano-structured brush can then be re-used for further functionalization. Although the opto-mechanically induced rupturing occurs for all surfactants, larger species do not penetrate deep enough into the brush such that after rupturing a leftover layer of polymer material remains on the substrate. This indicates that rupturing occurs predominantly in regions of high surfactant density.}, language = {en} }