Details

Autor(en) / Beteiligte

• Guillemet, Baptiste
• Faatz, Michael
• Gröhn, Franziska
• Wegner, Gerhard
• Gnanou, Yves

Titel

Nanosized Amorphous Calcium Carbonate Stabilized by Poly(ethylene oxide)-b-poly(acrylic acid) Block Copolymers

Ist Teil von

• Langmuir, 2006-02, Vol.22 (4), p.1875-1879

Ort / Verlag

Washington, DC: American Chemical Society

Erscheinungsjahr

2006

Quelle

MEDLINE

Beschreibungen/Notizen

• Particles of amorphous calcium carbonate (ACC), formed in situ from calcium chloride by the slow release of carbon dioxide by alkaline hydrolysis of dimethyl carbonate in water, are stabilized against coalescence in the presence of very small amounts of double hydrophilic block copolymers (DHBCs) composed of poly(ethylene oxide) (PEO) and poly(acrylic acid) (PAA) blocks. Under optimized conditions, spherical particles of ACC with diameters less than 100 nm and narrow size distribution are obtained at a concentration of only 3 ppm of PEO-b-PAA as additive. Equivalent triblock or star DHBCs are compared to diblock copolymers. The results are interpreted assuming an interaction of the PAA blocks with the surface of the liquid droplets of the concentrated CaCO3 phase, formed by phase separation from the initially homogeneous reaction mixture. The adsorption layer of the block copolymer protects the liquid precursor of ACC from coalescence and/or coagulation.