Biomimetic Morphogenesis of Calcium Carbonate in Mixed Solutions of Surfactants and Double-Hydrophilic Block Copolymers

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Written by: Grant England AP225 Fall, 2011

Info

Title: Biomimetic Morphogenesis of Calcium Carbonate in Mixed Solutions of Surfactants and Double-Hydrophilic Block Copolymers

Authors: Limin Qi,* Jie Li, and Jiming Ma

@Harvard: http://atmsp.whut.edu.cn/resource/pdf/7127.pdf

Keywords

surfactant, chemical synthesis, biomimetics, calcite, SDS, CaCO3, CTAB

Summary

This paper presented results of using cooperative effect of double hydrophilic block copolymers (DHBC) and DHBC-surfactant complexes in the creation of crystalline CaCO3 of various forms with shapes created by micelles.

Methods and Results

When using mixed poly(ethylene oxide)-block-poly(methacrylic acid)-sodium dodecylsulfate (PEO-b-PMAA-SDS), several different regimes were observed depending on the concentration of surfactant (SDS). When the SDS concentration was low, calcite spheres and dumb-bells were formed. When the SDS concentration was slightly higher (1 or 2 mM), hollow calcite spheres were created as shown in the figure below.

Surf1.jpg

When the concentration of surfactant was even higher, vaterite discs were formed as shown in the image below.

Surf2.jpg

Similar experiments were repeated using CTAB as the surfactant, and different structures (dumb-bells, peanuts, and pinecones) were produced.


Conclusions

This paper reports the first method for creating hollow micrometer-sized calcite spheres which could have potential applications. The spheres can be opened by sonication (and, indeed, some of them are open even when no sonication is done) in order to elucidate the thickness of the shells.