Pichon Benoît P, Cantin Sophie, Smulders Maarten M J, Vos Matthijn R J, Chebotareva Natalia, Popescu Daniela C, van Asselen Otto, Perrot Françoise, Sijbesma Rint, Sommerdijk Nico A J M
Laboratory of Macromolecular and Organic Chemistry and Department of Polymer Technology, Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands.
Langmuir. 2007 Dec 4;23(25):12655-62. doi: 10.1021/la7026225. Epub 2007 Nov 1.
To investigate the role and importance of nondirectional electrostatic interactions in mineralization, we explored the use of Langmuir monolayers in which the charge density can be tuned using supramolecular interactions. It is demonstrated that, in mixed Langmuir monolayers of bis-ureido surfactants containing oligo(ethylene oxide) and ammonium head groups associated with matching or nonmatching spacers between the two urea groups, the organization is controlled by molecular recognition. These different organizations of the molecules lead to different nucleation behavior in the mineralization of calcium carbonate. The formation of modified calcite and vaterite crystals was induced selectively by different phases of mixed monolayers, and they were characterized by SEM, TEM, and SAED. To understand the influence of the mixed Langmuir monolayers on the crystallization process, we studied the mixtures by means of (pi-A) isotherms and Brewster angle microscopy observations. Infrared reflection-absorption spectroscopy experiments were also performed on Langmuir-Schaefer films. From these results, we conclude that the local organization of the two systems discussed here gives rise to differences in both charge density and flexibility that together determine not only polymorph selection and the nucleation face but also the morphology of the resulting crystals.
为了研究非定向静电相互作用在矿化过程中的作用和重要性，我们探索了使用朗缪尔单分子层，其中电荷密度可通过超分子相互作用进行调节。结果表明，在含有聚环氧乙烷和铵头基的双脲基表面活性剂的混合朗缪尔单分子层中，两个脲基之间的间隔基匹配或不匹配，其分子排列由分子识别控制。这些不同的分子排列导致碳酸钙矿化过程中不同的成核行为。混合单分子层的不同相选择性地诱导了改性方解石和球霰石晶体的形成，并通过扫描电子显微镜（SEM）、透射电子显微镜（TEM）和选区电子衍射（SAED）对其进行了表征。为了理解混合朗缪尔单分子层对结晶过程的影响，我们通过（π-A）等温线和布鲁斯特角显微镜观察对混合物进行了研究。还对朗缪尔-谢弗薄膜进行了红外反射吸收光谱实验。从这些结果中，我们得出结论，这里讨论的两个体系的局部排列导致了电荷密度和柔韧性的差异，这些差异共同不仅决定了多晶型选择和成核面，还决定了所得晶体的形态。
