関連する実験動画
Updated: Aug 13, 2026

11:10
Fabrication and Operation of a Nano-Optical Conveyor Belt
Published on: August 26, 2015
触媒ナノモーター:ストライプナノロッドの自律的な動き
Walter F Paxton1, Kevin C Kistler, Christine C Olmeda
1Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Journal of the American Chemical Society
|October 14, 2004
まとめ
自動運転のジャヌスナノロッドは,過酸化水素溶液で秒速10回までの速度を達成する. 彼らの動きは,触媒酸素形成と界面張力によって駆動され,細菌の移動を模倣する.
科学分野:
- ナノテクノロジーと材料科学 ナノテクノロジーと材料科学
- 化学工学とカタリシス
- バイオ物理学と微流体学
背景:
- 合成マイクロ粒子の自律的な動きは,薬物投与およびマイクロロボティクスのアプリケーションにとって非常に重要です.
- プラチナ (Pt) と金 (Au) のセグメントで構成された棒状の粒子は,化学溶液の中で自己推進を示すことができます.
- 推進機構と関与する力を理解することは,その動きを制御する鍵です.
研究 の 目的:
- 水性過酸化水素溶液中のPt-Au Janusナノ棒の自律運動を調査する.
- 粒子の大きさ,速度,および発生する力との関係を決定する.
- 推進における触媒的酸素形成と界面現象の役割を明らかにする.
主な方法:
- 明確なPtとAuセグメント (1μmの長さ,370nmの直径) を有する棒状粒子の製造.
- 顕微鏡を用いた2~3%の過酸化水素溶液中の粒子運動の観測.
- 推進力を分析するために,コンベクション-拡散方程式を含む理論モデリング.
- エタノールと水の混合物での実験的検証と,さまざまな次元でのスケーリング研究.
主要な成果:
- 棒は,Pt端に向かって軸向的に,秒あたり10本体の長さまでの速度で移動した.
- 推進力は10〜14Nの大きさで,酸素濃度グラデーションと界面張力によって生成されます.
- 界面張力スケールではSR(2)gamma/muDLで,Sは酸素の進化速度,gammaは界面張力,Rは半径,muは粘度,Dは拡散係数,Lは長さを表しています.
- VelocityはSgammaに線形依存し,RとLに強い依存を示した.
- 黄金の表面にナノバブルの証拠があり,観測された運動方向を説明する可能性がある.
結論:
- Pt-Au Janus nanorodsは,細菌の運動性を模倣した自己推進性を示しています.
- 運動は,触媒的な酸素生成と,その結果生じる界面張力によって制御される.
- ナノバブルは,観測された方向運動と推進機構において重要な役割を果たす可能性がある.
さらに関連する動画
関連する概念動画
Motion Of A Charged Particle In A Magnetic Field
A charged particle experiences a force when moving through a magnetic field. Consider the field to be uniform and the charged particle to move perpendicular to it. If the field is in a vacuum, the magnetic field is the dominant factor determining the motion. Since the magnetic force is perpendicular to the direction of motion, a charged particle follows a curved path. The particle continues to follow this curved path until it forms a complete circle. Another way to look at this is that the...
Magnetic Force On Current-Carrying Wires: Example
In a magnetic field, moving charges encounter a force. If a wire contains these moving charges, i.e., if the wire is carrying a current, then a force acts on the wire as well. Consider a pair of flexible leads holding a wire that is 40 cm long and 10 g in weight in a horizontal position. The wire is placed in a constant magnetic field of 0.40 T, as shown in Figure 1(a). Determine the magnitude and direction of the current flowing in the wire needed to remove the tension in the supporting leads.
Torque On A Current Loop In A Magnetic Field
The most common application of magnetic force on current-carrying wires is in electric motors. These consist of loops of wire, which are placed between the magnets with a magnetic field. When current flows through the loops, the magnetic field applies torque, which causes the shaft to rotate, thus converting electrical energy to mechanical energy.
Consider a rectangular current-carrying loop containing N turns of wire, placed in a uniform magnetic field. The net force on a current-carrying loop...
Consider a rectangular current-carrying loop containing N turns of wire, placed in a uniform magnetic field. The net force on a current-carrying loop...
Magnetic Damping
Eddy currents can produce significant drag on motion, called magnetic damping. For instance, when a metallic pendulum bob swings between the poles of a strong magnet, significant drag acts on the bob as it enters and leaves the field, quickly damping the motion.
If, however, the bob is a slotted metal plate, the magnet produces a much smaller effect. When a slotted metal plate enters the field, an emf is induced by the change in flux; however, it is less effective because the slots limit the...
If, however, the bob is a slotted metal plate, the magnet produces a much smaller effect. When a slotted metal plate enters the field, an emf is induced by the change in flux; however, it is less effective because the slots limit the...
Design Example: Frog Muscle Response
A student is tasked to work on an intriguing experiment involving an RL (Resistor-Inductor) circuit to study the muscle response of a frog's leg to electrical stimulation. The RL circuit plays a crucial role in this experiment, providing the means to control and measure the electrical impulses that trigger muscle contraction.
When the switch connecting the RL circuit is closed, a brief muscle contraction is observed. This is because, at a steady state, the inductor acts like a short circuit,...
When the switch connecting the RL circuit is closed, a brief muscle contraction is observed. This is because, at a steady state, the inductor acts like a short circuit,...
Torque Free Motion
The torque-free motion refers to the movement of a rigid body in space when no external torques are acting upon it. This type of motion can be observed in environments where there are no external forces or frictions, like in outer space. For example, a rotation of Mars in space is a torque-free motion. Mars is an axisymmetric object, meaning it has an axis of symmetry along which it rotates, designated as the z-axis. The rotating frame of reference is defined such that the center of mass of...

