Article pubs.acs.org/JPCB
Magnetic Field Effects on Copper Metal Deposition from Copper Sulfate Aqueous Solution Chikako Udagawa,*,† Aya Maeda,† Akio Katsuki,‡ Syou Maki,† Shotaro Morimoto,† and Yoshifumi Tanimoto*,† †
Faculty of Pharmacy, Osaka Ohtani University, Tondabayashi 584-8540, Japan Faculty of General Education, Shinshu University, Matsumoto 390-8621, Japan
‡
S Supporting Information *
ABSTRACT: Effects of a magnetic field (≤0.5 T) on electroless copper metal deposition from the reaction of a copper sulfate aqueous solution and a zinc thin plate were examined in this study. In a zero field, a smooth copper thin film grew steadily on the plate. In a 0.38 T field, a smooth copper thin film deposited on a zinc plate within about 1 min. Then, it peeled off repeatedly from the plate. The yield of consumed copper ions increased about 2.1 times compared with that in a zero field. Mechanism of this magnetic field effect was discussed in terms of Lorentz force- and magnetic force-induced convection and local volta cell formation.
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strate clearly that magnetic fields constitute a unique tool for the control of chemical and physical processes. Earlier, we investigated the effects of strong magnetic fields of 8−15 T on electroless metal deposition reactions.19−28 When a metal with high ionization tendency is soaked in an aqueous solution of another metal ion with a low ionization tendency, the metal ion in the solution is deposited as metal along with dissolution of the metal with high ionization tendency because of the difference in their ionic tendencies. We studied MFEs on silver dendrite formation. The dendrite was prepared by reacting a copper metal bar and a silver nitrate aqueous solution soaked in filter paper.19,20 Applying a horizontal 8 T field caused the silver dendrite deposition, mainly near the two bar ends, although it was deposited almost uniformly around the bar. Copper dendrite was prepared using a reaction of a zinc metal bar and copper chloride aqueous solution soaked in filter paper.22 Application of a horizontal 8 T field caused copper dendrite deposition mainly near the bar center, although it was deposited almost uniformly around the bar. These results were interpreted in terms of magnetic force acting on paramagnetic copper ion intervening in the reaction. However, when the silver dendrite formation was undertaken in a vertical 15 T field, the pattern changed remarkably.24−28 The magnetic field strongly affected the three-dimensional silver dendrite. Black and round dendrites were obtained in the magnetic field, whereas metallic crystals were grown in a zero
INTRODUCTION Elucidating how magnetic fields affect chemical and physical phenomena is of great interest because magnetism is an important and fundamental physical property of matter. Magnetic fields are believed to offer the potential to control various chemical and physical phenomena.1 Magnetic fields can affect photochemical reactions,2−8 thermal reactions,9−13 electrochemical reactions,14−16 and others. Regarding photochemical reactions of organic molecules, the mechanisms of magnetic field effects (MFEs) are mainly explainable by a radical pair mechanism. Today, MFEs are used as probes to clarify reaction processes5,6 and for sensing microenvironments in which organic molecules are present.7,8 For thermal reactions, three-dimensional morphological chirality of membrane tubes prepared by a chemical garden reaction (reaction of zinc sulfate crystal and sodium silicate aqueous solution) is known to be controllable using a strong magnetic field of 5−15 T.9−11 In MFEs of a Belousov−Zhabotinsky reaction in a thin glass tube,12,13 an applied magnetic field (≤4 T) strongly affects the chemical wavefront propagation rate: The results were interpreted in terms of magnetic force-induced convection at the wavefront. Regarding electrochemical reactions, effects of external magnetic field have been studied extensively as reviewed elsewhere.14−16 Moreover, new and interesting phenomena have been reported: Polyaniline film electrodes prepared using a magnetoelectropolymerization method (5 T) are useful for chirality recognition of L-ascorbic and D-ascorbic acids using cyclic voltammetry,17 and that electrodes covered with magnetoelectrodeposited copper film (5 T) are useful for chirality recognition of tartaric acid.18 These results demon© 2014 American Chemical Society
Received: February 13, 2014 Revised: April 16, 2014 Published: April 16, 2014 4889
dx.doi.org/10.1021/jp5015675 | J. Phys. Chem. B 2014, 118, 4889−4894
The Journal of Physical Chemistry B
Article
field. The results were interpreted in terms of magnetic-force induced convection. As described briefly above, electroless metal deposition is a simple and interesting reaction exhibiting different aspects of MFEs. To date, our main interest has been investigation of the effects of a strong magnetic field (>1 T). However, although research of weak fields has been little reported, the effects of weak magnetic fields (
