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Synthesized Amphiphilic St-AA Copolymers Modulate Calcium Carbonate Crystal Habit And Morphogenesis

Posted on:2007-10-31Degree:MasterType:Thesis
Country:ChinaCandidate:P SunFull Text:PDF
GTID:2121360182486935Subject:Applied Chemistry
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Due to the micro-phase separation of structure unit, Amphiphilic copolymers can self-assemble many types of ordered micellar structure in solution and function as templates to induce the crystallization of calcium carbonate. The variation of PAS composition affects the array of functional group on the molecular chain / solubility and micellization behavior;besides, the distribution of hydrophilic block in chain affect the cognition in the inorganic-organic interface. Accordingly, amphiphilic copolymers with different composition may exert distinct effect on crystal habit and morphogenesis of CaCO3.Amphiphilic copolymer of poly(styrene and acrylic acid) (PAS) was used as template, with its varying compositions of hydrophilic and hydrophobic unit, to synthesize calcium carbonate in solution. By means of SEM/ XRD/ TG-DTA/ IR and particle-size analyzer, the morphology/ size/ texture/ and structure of the samples were characterized and investigated to find out factors which have influence on CaCO3 property (such as morphology, crystal habit,et al. ), the formation mechanism of samdwich structure was explored and proposed.Results of TG-DTA and FTIR show that all samples are composites consist of PAS and CaCO3 crystallites;XRD/ SEM and FTIR disclose that effect which PAS of varying compositions play on the crystallizationand morphogenesis of CaCO3 are different;Artificially it is the first time to synthesize CaCO3 with samdwich structure. In solution contained P3:], through examination the morphology evolvement of such infrequent structure and exploring the influences that initial supersaturation , concentration of polymer had on CaCO3, it is proposed that formation of samdwich structure is according to mechanisms of insoluble matrices;furthermore insoluble matrices and flake crystal are the basic factors in such process, we demonstrate the formation of such structure. By changing polarity of solution with the addition of isopropanol, the template effect of matrices is proved.The PAS of varying-composition was utilized to regulate crystal habit and morphogenesis of other inorganic materials such as BaCO3. Rod and spindle-like particles were obtained;With the increasing content of AA unit, PAS modulate CaCO3 to crystal as primary nano-particles and farther assemble under the template influence of PAS micells.
Keywords/Search Tags:CaCO3, amphiphilic copolymer composition, crystal habit, morphogenesis.
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