Thermal Modulation of Nanomotor Movement

Abstract

Motion control is essential for various applications of man-made nanomachines. The ability to control and regulate the movement of catalytic nanowire motors is illustrated by applying short heat pulses that allow the motors to be accelerated or slowed down. The accelerated motion observed during the heat pulses is attributed primarily to the thermal activation of the redox reactions of the H(2)O(2) fuel at the Pt and Au segments and to the decreased viscosity of the aqueous medium at elevated temperatures. The thermally modulated motion during repetitive temperature on/off cycles is highly reversible and fast, with speeds of 14 and 45 microm s(-1) at 25 and 65 degrees C, respectively. A wide range of speeds can be generated by tailoring the temperature to yield a linear speed-temperature dependence. Through the use of nickel-containing nanomotors, the ability to combine the thermally regulated motion of catalytic nanomotors with magnetic guidance is also demonstrated. Such on-demand control of the movement of nanowire motors holds great promise for complex operations of future manmade nanomachines and for creating more sophisticated nanomotors.

Fabrication of Micro/Nanoscale Motors

“…The speed of Pt/Au nanowires was substantially increased upon exposure to elevated temperatures. 225 Similar phenomena were found for bubble-propelled microtubes, which have been employed to compensate the effect of reducing the fuel level. 119 The motion behavior of electrically driven micro/nanomotors can be modulated by controlling the applied electric field.…”

Diffusive behaviors of circle-swimming motors

“…Their motion can be controlled using external magnetic fields [19,21] as well as chemical [22][23][24] and thermal [25] fields. Catalytic bimetallic nanomotors propel themselves by electrocatalytically decomposing hydrogen peroxide (H 2 O 2 ) [7,14,26,27] through a mechanism we recently described as reaction induced charge autoelectrophoresis (RICA) [26,27].…”

Electrokinetic effects in catalytic platinum-insulator Janus swimmers

“…This has great potential significance as the effect on the swimming behaviour, of solution properties such as temperature [29], contaminants [30], pH, and salt concentration are of critical importance to potential applications that could eventually include drug delivery in the body [2]. Here, we focus in particular on the effect of salt-concentration on their swimming behaviour.…”