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Stable dispersions of nanosilica ranging in size between 8 and 11 nm were coated with tert-butyl acrylate polymer by in situ polymerization of monomer adsorbed on the particles in 2-propanol. The system was developed for use in the encapsulated inorganic resist technology. To achieve a high coating efficiency, silica was first modified with the 3-(trimethoxysilyl)propylmethacrylate (MPS) coupling agent at two different degrees of grafting. The presence of the bound MPS agent and of the polymer at the silica surface was determined by the attenuated total reflection infrared spectroscopy, while the amounts bound were assessed by the thermogravimetric analysis. Under studied conditions, the encapsulation efficiency was governed by the degree of MPS grafting and by the initial concentration of the monomer. Finally, the dissolution rate of these particles in aqueous base, a key parameter in photoresist application, was drastically reduced with increasing amount of grafted tert-butyl acrylate polymer at the silica surface.

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Catalytic decomposition of urea by enzyme urease in aqueous strontium and barium chloride solutions was used to rapidly precipitate witherite (BaCO3) and strontianite (SrCO3) particles at room temperature. At the early stages of the process, uniform spheroidal particles were generated, which were shown to consist of nanosized subunits. On continuous aging of the same systems the additionally precipitated alkali earth carbonates grow as whiskers onto original core particles, which eventually fully transform into crystalline rodlike clusters.

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