title: Bioinspired thermo- and pH-responsive polymeric amines: multimolecular aggregates in aqueous media and matrices for silica/polymer nanocomposites.
abstract: Polymeric amines have been intensively studied for application in smart systems and as matrices for the design of composite materials, including bioinspired substances. A new thermo- and pH-responsive polymer was obtained by radical polymerization of N-(3-(diethylamino)propyl)-N-methylacrylamide. Upon heating, the polymer precipitated from aqueous solutions above pH 9; the observed cloud point was dependent on the polymer concentration and decreased from 95°C at pH 9 to 40°C at pH 11. The basicity of the polymer decreased at elevated temperatures owing to an increase in the hydrophobicity-driven compaction of the macromolecules. Dynamic light scattering analysis demonstrated that the formation of large multimolecular associates with radius 1000-2000 nm was initiated from 1 to 2°C below the cloud point. The new polymer is demonstrated to be an effective matrix for various siliceous composite structures, including 200-300 nm solid spherical raspberry-like particles and hollow hemispherical particles of more than 1000 nm diameter. Condensation of silicic acid in the presence of polymeric amines is a model reaction in biosilicification studies, and the obtained data are also discussed from the perspective of the matrix hypothesis for biosilica formation.
authors: Limnological Institute Siberian Branch of the Russian Academy of Sciences, 3, Ulan-Bator Str., Irkutsk 664033, Russia.
authors: Elena N
authors: EN
authors: Danilovtseva
authors: Laboratory of Polymer Chemistry, Department of Chemistry, University of Helsinki, A.I. Virtasen aukio 1, P.O. Box 55, FIN-00014 HY Helsinki, Finland.
authors: Vladimir
authors: V
authors: Aseyev
authors: Vinogradov Institute of Geochemistry Siberian Branch of the Russian Academy of Sciences, 1a Favorsky Str., Irkutsk 664033, Russia.
authors: Olga Yu
authors: OY
authors: Belozerova
authors: Limnological Institute Siberian Branch of the Russian Academy of Sciences, 3, Ulan-Bator Str., Irkutsk 664033, Russia.
authors: Stanislav N
authors: SN
authors: Zelinskiy
authors: Limnological Institute Siberian Branch of the Russian Academy of Sciences, 3, Ulan-Bator Str., Irkutsk 664033, Russia. Electronic address: annenkov@lin.irk.ru.
authors: Vadim V
authors: VV
authors: Annenkov
mesh_terms: D000588:Amines / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D046911:Macromolecular Substances / Q000737:chemistry*; D053761:Nanocomposites / Q000737:chemistry*; D010316:Particle Size; D011108:Polymers / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D000588:Amines; D046911:Macromolecular Substances; D011108:Polymers; D014867:Water; D012822:Silicon Dioxide
keywords: Association; Biomineralization; Dynamic light scattering; Polyamines; Polyelectrolytes; Silica; Thermo-responsible polymer