title: Oriented aggregation and novel phase transformation of vaterite controlled by the synergistic effect of calcium dodecyl sulfate and n-pentanol.
abstract: Calcium dodecyl sulfate (CDS) was used for the first time both as an anionic surfactant and as the source of mineral ions in the precipitation process of calcium carbonate (CaCO3). The simple reaction of the enriched Ca2+ ions at the so-called organic-inorganic interfaces with the slowly bubbled CO2 gas resulted in the metastable vaterite polymorph with various structures. The single-crystalline vaterite of the hexagonal platelets, the lens-shaped structures with hexagonal symmetry, the olive-shaped superstructures and these with a concave at each top of olives, and another metastable polymorph of aragonite were obtained, respectively, depending upon the concentration ratio between CDS and n-pentanol. The synergistic effect of CDS and n-pentanol is believed to play a crucial role in driving the oriented aggregation of metastable nanoparticles. Simultaneously, the novel phase transformation of vaterite to aragonite was observed, implying the possible formation mechanism of aragonite at room temperature and in the absence of magnesium ions.
authors.affiliation: Key Laboratory for Colloid and Interface Chemistry of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Ji'nan 250100, China. qshen@sdu.edu.cn
authors.forename: Qiang
authors.initials: Q
authors.lastname: Shen
authors.forename: Liancheng
authors.initials: L
authors.lastname: Wang
authors.forename: Yaping
authors.initials: Y
authors.lastname: Huang
authors.forename: Jinglun
authors.initials: J
authors.lastname: Sun
authors.forename: Haihua
authors.initials: H
authors.lastname: Wang
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhou
authors.forename: Dujin
authors.initials: D
authors.lastname: Wang
mesh_terms: D002119:Calcium Carbonate / Q000737:chemistry*; D002412:Cations; D003460:Crystallization; D004357:Drug Synergism; D008274:Magnesium / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D000439:Pentanols / Q000737:chemistry*; D044367:Phase Transition; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry*; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry*; D013696:Temperature
chemical_list: D002412:Cations; D000439:Pentanols; D013501:Surface-Active Agents; D012967:Sodium Dodecyl Sulfate; C028913:dodecyl sulfate; D002119:Calcium Carbonate; D008274:Magnesium; C024999:n-pentanol