Fluid flow is ubiquitous in many environments that form habitats for microorganisms. Therefore, it not surprising both biological and artificial microswimmers show responses to flows are determined by the interplay of chemical physical factors. In particular, deepen understanding how different systems respond flows, crucial comprehend influence played swimming pattern. The tendency organisms navigate up or down termed rheotaxis. Early theoretical studies predicted a positive rheotactic...

A hybrid micromotor is an active colloid powered by more than one power source, often exhibiting expanded functionality and controllability those of a singular energy source. However, these sources are applied orthogonally, leading to stacked propulsion that just sum two independent mechanisms. Here, we report TiO2–Pt Janus micromotors, when subject both UV light AC electric fields, move up 90% faster simply adding the speed either This unexpected synergy between propose, arises from fact...

There is mounting interest in synthetic microswimmers ("micromotors") as microrobots well a model system for the study of active matters, and spatial navigation critical their success. Current navigational technologies mostly rely on magnetic steering or guiding with physical boundaries, yet limitations these strategies are plenty. Inspired by an earlier work domains garnet film predefined tracks, we present interdigitated microelectrodes (IDE) where, upon application AC electric fields,...

Abstract Microrotors are an indispensable component in micromachines, yet their usefulness has been limited by a lack of simple, inexpensive, and controlled fabrication technique that yields microrotors shapes large quantities. To address this challenge, the chemical synthesis, characterization, activation tadpole‐shaped catalytic consist spherical, platinum (Pt)‐coated head silver (Ag) nano‐tail tunable lengths reported herein. Importantly, tail spontaneously grows on Pt aqueous solution Ag...

The ability of artificial microswimmers to respond external stimuli and the mechanistical details their origins belong most disputed challenges in interdisciplinary science. Therein, creation chemical gradients is technically challenging, because they quickly level out due diffusion. Inspired by pivotal stopped flow experiments kinetics, we show that microfluidics gradient generation combined with a pressure feedback loop for precisely controlling stop flows, can enable us study chemotaxis...

Bio‐hybrid robotics at the microscale promises to advance intelligent systems in biomedical devices, environmental monitoring, and soft by emulating complex behaviors found living entities, such as chemotaxis. Here, shape‐dependent chemotaxis of doublet microswimmers, with various morphologies that exhibit autonomous movement hydrogen peroxide ( ) gradients without need for material preparation, are reported. These microswimmers consist a double‐sphere structure composed one colloid...

Most Janus particle microswimmers use catalytic reaction mechanisms, including hydrogen peroxide or hydrazine degradation, to generate gradients for self-propulsion. However, several alternative reac- tion mechanisms can also lead activity,...

In order to move toward realistic applications by extending active matter propulsion reactions beyond the classical catalytic hydrogen peroxide decomposition, we investigate self-propulsion mechanism of Janus particles. To address influences ionic species, particles driven a galvanic exchange reaction that consumes and produces ions on one hemisphere. Our galvanophoretic experiments in regime thin Debye layers confirm even simplest models are still full important surprises. We find...

The design of powerful, more biocompatible microrobots calls for faster catalytic reactions. Here we demonstrate a two-fold increase in the speed photocatalytic TiO2-metal Janus micromotors via Au/Ag bi-layered coating. Electrochemical measurements show that such bimetallic coating is better photocatalyst than either metal alone. Similarly, an additional sputtered Ag layer could also significantly Pt-PS or TiO2-Pt micromotors, suggesting applying coatings generalizable strategy micromotors.

The emerging field of active matter, and its subset colloid, is in great need good model systems consisting moving entities that are uniform highly tunable. In this article, we address challenge by introducing core-shell SiO2-TiO2 microspheres, prepared chemically coating a thin layer TiO2 on an inert core, monodisperse size (polydispersity 4.1%) regular shape (circularity 0.93). Compared with similar samples the classic sol-gel method, Janus TiO2-Pt colloids spheres move faster boast much...

Chemiophoretic nano- and micromotors require a constant flow of product molecules to maintain gradient that enables their propulsion. Apart from smaller number redox reactions have been used, catalytic are the main source energy with obvious benefit making on-board fuel storage obsolete. However, decomposition H2O2 seems strongly dominate literature although motion in H2O through water splitting is becoming more popular, so far only few different used for propulsion photocatalytic...

Micromotors are propelled by a variety of chemical reactions, with most them being catalytic nature. There are, however, systems based on redox which show clear benefits for efficiency. Here, we broaden the spectrum suitable reactions to galvanic exchange processes, or an electrochemical replacement solid metal layer dissolved ionic species more noble metal. We study details motility and influence different reaction parameters conclude that these galvanophoretic processes circumvent several...

Fluid flow is ubiquitous in many environments that form habitats for microorganisms. The tendency of organisms to navigate towards or away from termed rheotaxis. Therefore, it not surprising both biological and artificial microswimmers show responses flows are determined by the interplay chemical physical factors. In particular, deepen understanding how different systems respond flows, crucial comprehend influence played swimming pattern. recent studies, pusher-type Janus particles exhibited...

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 self-electrophoretic micromotor which slides along wall and measures necessary disengage motor from wall. Our experiments unveil that required disengaging increases with chemical driving, often surpassing both motor's effective gravity its propulsive thrust. Experimental results...

Abstract Die Fähigkeit künstlicher Mikroschwimmer, auf äußere Reize zu reagieren und deren mechanistische Ursprünge, gehören den umstrittensten Fragen der interdisziplinären Wissenschaft. Erzeugung chemischer Gradienten ist dabei eine technische Herausforderung, da sie aufgrund von Diffusion schnell abflachen. Inspiriert ‘Stop‐flow’ Experimenten aus chemischen Kinetik zeigen wir, dass die eines mikrofluidischen durch Kombination mit einer Druckrückkopplungsschleife zur präzisen Kontrolle des...

The ability of artificial microswimmers to respond external stimuli and the mechanistical details their origins belong most disputed challenges in interdisciplinary science. Therein, creation chemical gradients is technically challenging, because they quickly level out due diffusion. Inspired by pivotal stopped flow experiments kinetics, we show that microfluidics gradient generation combined with a pressure feedback loop for precisely controlling stop flows, can enable us study chemotaxis...