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Polymer Journal (2012) 44, 586593 & 2012 The Society of Polymer Science, Japan (SPSJ) All rights reserved 0032-3896/12 http://www.nature.com/PJ
Web End =www.nature.com/pj
Yuka Tanaka and Kensuke Naka
Size-controlled CaCO3 particles were obtained using a carbonate-controlled addition method with a carboxylate-terminated hyperbranched poly(amidoamine) (HYPAM-ONa). The crystalline phase of CaCO3 particles was determined to be thermodynamically unstable vaterite. The average size of the CaCO3 particles decreased from 1.30.2 to 0.360.18 mm with an increase in the incubation time of HYPAM-ONa-Ca2 solution from 3 min to 72 h. Interactions of the CaCO3 particles in aqueous dispersions with different types of commercially available ionic polymers that is, poly(acrylic acid), poly(sodium 4-styrenesulfonate), poly(diallyldimethylammonium chloride) and poly(arylamine) (PAAM) were studied. Surface coating of the CaCO3 particles with PAAM, an aqueous dispersion, was successfully achieved by the addition of a specied concentration of the polymer. The surface-coated CaCO3 particles with gold nanoparticles were obtained by addition of an aqueous solutionof gold nanoparticles stabilized with HYPAM-ONa to an aqueous dispersion of the CaCO3 particles and subsequent additionof HAuCl4 and formaldehyde as a reducing agent.
Polymer Journal (2012) 44, 586593; doi:http://dx.doi.org/10.1038/pj.2012.28
Web End =10.1038/pj.2012.28; published online 28 March 2012
Keywords: calcium carbonate; carbonate-controlled addition method; gold nanoparticles; hyperbranched polymer; vaterite
INTRODUCTION
Because of their special properties and low cost, considerable attention has been given to synthetic organicinorganic hybrid materials, which are inspired by biominerals.16 The main inorganic
mineral produced in natural organisms is CaCO3; organicinorganic hybrid materials containing CaCO3 are of great interest for industrial and technological applications. To develop methods for preparation of new CaCO3 polymer hybrid materials, a fundamental understanding of binding kinetics and mechanisms of crystallization in organic polymerCa2 complexes are required.711 Among various methods for preparation of CaCO3 polymer hybrid materials, carbonate-controlled addition is a way to control the mineralization of CaCO3 by simply changing the incubation time of the polymer
Ca2 complexation process in aqueous solutions before addition of
CO32 ions.12 We showed that the carbonate-controlled addition method using poly(acrylic acid) (PAA) resulted in the formation of stable amorphous calcium carbonate composite particles.12 The resulting amorphous calcium carbonate composite particles were monodispersed spheres, and the average particle size increased from 0.180.04 to0.550.12 mm with an increase in the incubation time of the PAA
CaCl2 aqueous solution from 3 min...