Measuring Attractive Interaction between a Self-Electrophoretic Micromotor and a Wall.

Chemically driven micromotors exhibit a pronounced affinity for nearby surfaces, yet the quantification of this motor-wall interaction strength remains unexplored in experiments. Here, we apply an external force to a self-electrophoretic micromotor which slides along a wall and measures the force necessary to disengage the motor from the wall. Our experiments unveil that the required disengaging force increases with the strength of chemical driving, often surpassing both the motor's effective gravity and its propulsive thrust.

Experimental and Numerical Study on Dynamic Response of Foam-Nickel Sandwich Panels under Near-Field Blast Loading.

The explosion products, such as shock waves, fragments and heat energy formed by explosion, act on the plate structure, which may cause structural damage, material failure and even phase transformation of material. In this paper, the damage mechanism and protective effect of near-field blast load on sandwich structure based on foam-nickel core material were studied. Firstly, the near-field explosion test was conducted to investigate the blast response of the foam-nickel sandwich structure subjected to blast shock from 8701 explosive at near-field position.

Ultrasonic Steering Wheels: Turning Micromotors by Localized Acoustic Microstreaming.

The ability to steer micromotors in specific directions and at precise speeds is highly desired for their use in complex environments. However, a generic steering strategy that can be applied to micromotors of all types and surface coatings is yet to be developed. Here, we report that ultrasound of ∼100 kHz can spin a spherical micromotor so that it turns left or right when moving forward, or that it moves in full circles.

Generic Rules for Distinguishing Autophoretic Colloidal Motors.

Distinguishing the operating mechanisms of nano- and micromotors powered by chemical gradients, i.e. "autophoresis", holds the key for fundamental and applied reasons.

Better fuels for photocatalytic micromotors: a case study of triethanolamine.

Efficient fuels are critical for designing photocatalytic micromotors with high performance. We discover that 0.5 mM of triethanolamine can power TiO-Pt motors at 35 μm s without producing bubbles, a significant improvement over conventional fuels such as water, HO or hydroquinone.

Active, Yet Little Mobility: Asymmetric Decomposition of HO Is Not Sufficient in Propelling Catalytic Micromotors.

A popular principle in designing chemical micromachines is to take advantage of asymmetric chemical reactions such as the catalytic decomposition of HO. Contrary to intuition, we use Janus micromotors half-coated with platinum (Pt) or catalase as an example to show that this ingredient is not sufficient in powering a micromotor into self-propulsion. In particular, by annealing a thin Pt film on a SiO microsphere, the resulting microsphere half-decorated with discrete Pt nanoparticles swims ∼80% more slowly than its unannealed counterpart in HO, even though they both catalytically produce comparable amounts of oxygen.

Light-powered active colloids from monodisperse and highly tunable microspheres with a thin TiO shell.

The emerging field of active matter, and its subset active colloid, is in great need of good model systems consisting of moving entities that are uniform and highly tunable. In this article, we address this challenge by introducing core-shell SiO2-TiO2 microspheres, prepared by chemically coating a thin layer of TiO2 on an inert core, that are highly monodisperse in size (polydispersity 4.1%) and regular in shape (circularity 0.

Synergistic Speed Enhancement of an Electric-Photochemical Hybrid Micromotor by Tilt Rectification.

A hybrid micromotor is an active colloid powered by more than one power source, often exhibiting expanded functionality and controllability than those of a singular energy source. However, these power sources are often applied orthogonally, leading to stacked propulsion that is just a sum of two independent mechanisms. Here, we report that TiO-Pt Janus micromotors, when subject to both UV light and AC electric fields, move up to 90% faster than simply adding up the speed powered by either source.