Poly(ethylene glycol) acrylate-block-(methacrylic acid) copolymer (PEGA-PMAA) having double-hydro-philic groups was synthesized and characterized. The morphology of the CaCO_3 particles formed in the presence of PEGA-PMAA was investigated, which was compared with the CaCO_3 particles formed in Lhe presence of poly (ethylene glycol) acrylate (PEGA) having single-hydrophilic group. The results show that the morphology of CaCO_3 particles varies with the polymers presented. The size of the CaCO_3 particles controlled by PEGA is smaller than that in water. However, the size of the CaCO_3 particles controlled by PEGA-PMAA is much larger. Especially, the flower-shaped calcite with large length of about 7 μm is very interesting. This indicates that PEGA prevents the growth of the CaCO_3 particles, while PEGA-PMAA promotes the growth of the CaCO_3 particles.

Key words: PROPENOIC ACID ESTER, POLYMER, METHYLPROPENOIC ACID, CALCIUM CARBONATE, GROWTH