New hybrid polyoxazolines (CubePOZO) were synthesized by ring-opening polymerization of 2-methyl-2-oxazoline initiated by functionalized polyhedral oligomeric silsesquioxane (POSS) with various feed ratios. The hybrid micelles derived from CubePOZO with both seven hydrophobic cyclopentyl groups of POSS and polyoxazoline (POZO) as a hydrophilic segment were prepared in an aqueous phase. Compared to POZO initiated by cyclohexyl iodide or methyl p-toluenesulfonate, increased hydrophobicity caused by the structure of POSS in CubePOZO played a major role in the micelle formation. This depended on the amount of POSS incorporated into the POZO. The CubePOZO100 and CubePOZO200 formed micelles in an aqueous phase with critical micelle concentrations (cmc) of 55 and 100 mg/L, respectively. Transparent polymer hybrids, homogeneous dispersion of hydrophobic POSS bonded covalently to POZO in the silica gel matrix at the molecular level, were obtained through hydrogen-bonding interaction between CubePOZO and silica gel. The obtained polymer hybrids from CubePOZO showed excellent solvent resistance, similar to that of polymer hybrids having an interpenetrating polymer network structure. It was concluded that the solvent-resistant property came from the size of POSS and the hydrophobic interaction between the POSS in the silica gel matrix. In addition, thermal stability of the polymer hybrids from CubePOZO was much increased compared to that of the polymer hybrids from homoPOZO and POSS.

Three different crystal polymorphs of CaCO 3 (aragonite, vaterite and calcite) have been selectively induced by changing the time of addition of a radical initiator to a calcium carbonate solution containing sodium acrylate.

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We examined the crystallization of CaCO 3 by changing the time of addition of the G1.5 and G3.5 poly(amidoamine) dendrimers to a calcium carbonate solution after incubation for several minutes (1, 3, 20, or 60 min) at 30 C. Based on the fact that the crystal phase obtained in the absence of the dendrimer was calcite, the dendrimers effectively stabilized the most unstable vaterite particles, even delaying the addition time of the dendrimer for 60 min. As the delayed addition time of the G1.5 dendrimer increased from 0 to 60 min, the particle size increased from 1:2 AE 0:5 to 4:7 AE 0:7 mm. As the generation number of the dendrimer increased from G1.5 to G3.5, the particle size of the spherical vaterite decreased under the same condition. The present results suggest that the anionic PAMAM dendrimers effectively modified the metastable vaterite surface and inhibited the further growth of vaterite particles by changing the addition time.Biological inorganic materials have superior mechanical properties those of synthetic materials. The modelling of biomineralization is a promising approach to controlled crystal growth for seeking materials analogous to those produced by nature. 1,2 The majority of these efforts have focused on exploring the promoting effect of templates on crystal nucleation and growth. On the specific interactions, various synthetic polymers have been found to be potent inhibitors or habit modifiers for inorganic crystallization by adsorption onto the surfaces of the growing crystals, thus controlling their growth rate and habit through the strength and selectivity of this adsorption. 3-7 The final crystalline phase arises through a series of steps. By selectively interacting with the minerals at different stages during the crystal forming process, the organisms may choose manipulating both the polymorph and the orientation of the mineral to meet specific biological requirements. Although the presence of various synthetic additives has been studied for inorganic crystallization, selective interaction of an organic matrix with the mineral at different stages has been unexplored. Recently, we have reported a new concept for controlling crystal polymorphs of CaCO 3 by interaction of a synthetic additive at different nucleation stages. 8 We used sodium acrylate and a water-soluble radical initiator for selectively interacting with the mineral at different stages during the crystal-forming process. While sodium acrylate does not affect nucleation and growth of crystals, poly(acrylate) affects crystal morphology by inhibiting the growth of particular crystal faces.Recently, dendrimers are receiving increasing attention because of their unique structures and properties. 9-11 Generally, dendrimers of lower generations tend to exist in relative open forms with high overall symmetries, which are different from linear polymers and classical micelles formed by intermolecular aggregation. The dendrimers are highly regular branchedstructure and monodisperse macromolecules. The dendrimers also provide reaction si...

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