Three-dimensional morphological chirality induction using high magnetic fields in membrane tubes prepared by a silicate garden reaction
Three-dimensional morphological chirality induction using high magnetic fields in membrane tubes prepared by a silicate garden reaction
复制标题
DOI：
10.1021/jp050469m
复制
发表时间：
2005-07-21
影响因子：
3.3
通讯作者：
Tanimoto, Y
中科院分区：
文献类型：
--
作者：
Duan, WY;Kitamura, S;Tanimoto, Y
使用垂直超导磁体（最大15 T），我们研究了磁场对由硅酸盐花园反应制备的膜管形态的影响。在零电场条件下，向硅酸钠水溶液中加入金属盐时，半透膜管向上生长。在磁场（15 T，向下）存在下，当加入氯化镁和硫酸铜时，右旋螺旋膜管沿着玻璃容器的内表面生长。以制备中使用的金属阳离子的名称来指代膜管，在Mg（II）和Zn（II）膜管的情况下，当场方向向上反转时，左手螺旋管生长。将玻璃棒置于容器中，在磁场中生长左手螺旋Mg（II）膜管。与血管壁分离的Mg（II）和Zn（II）管在磁场中以扭曲的形状生长。反应过程中溶液运动的原位观察表明，从中空膜管的开口顶部流出的洛伦兹力引起管出口附近的溶液的对流，从而产生膜管的手性生长。流出和边界（容器壁或玻璃棒表面）的相对取向有助于确定对流的方向。
Using a vertical superconducting magnet (max. 15 T), we studied magnetic field effects on membrane tube morphology prepared by a silicate garden reaction. At zero field, semipermeable membrane tubes grew upward when metal salts were added to a sodium silicate aqueous solution. In the presence of a magnetic field (15 T, downward) right-handed helical membrane tubes grew along a glass vessel's inner surface when magnesium chloride and copper sulfate were added. Refer-ring to membrane tubes by the names of metal cations used in their preparation, in the case of Mg(II) and Zn(II) membrane tubes, the left-handed helical tubes grew when the field direction was reversed upward. The left-handed helical Mg(II) membrane tubes grew in the magnetic field when a glass rod was placed in a vessel. Mg(II) and Zn(II) tubes, separate from a vessel wall, grew in a twisted shape in the magnetic field. In situ observation of the solution's motion during the reaction revealed that the Lorentz force on the outflow from the opened top of the hollow membrane tube induced convection of the solution near the tube exit, engendering chiral growth of the membrane tubes. Relative orientation of the outflow and a boundary (a vessel wall or glass rod surface) helped to determine the convection's direction.