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This work reports a reversible braking system for micromotors that can be controlled by small temperature changes (≈5 °C). To achieve this, gated‐mesoporous organosilica microparticles are internally loaded with metal catalysts (to form the motor) and the exterior (partially) grafted with thermosensitive bottle‐brush polyphosphazenes to form Janus particles. When placed in an aqueous solution of H2O2 (the fuel), rapid forward propulsion of the motors ensues due to decomposition of the fuel. Conformational changes of the polymers at defined temperatures regulate the bubble formation rate and thus act as brakes with considerable deceleration/acceleration observed. As the components can be easily varied, this represents a versatile, modular platform for the exogenous velocity control of micromotors. [ABSTRACT FROM AUTHOR]

Manganese ions are embedded in microporous silica nanoparticles to catalyse the degradation of the H SB 2 sb O SB 2 sb "fuel" to water and gaseous oxygen. Keywords: bottle-brush polymers; mesoporous silica; micromotors; microparticles; polyphosphazenes EN bottle-brush polymers mesoporous silica micromotors microparticles polyphosphazenes 3187 3187 1 02/17/21 20210215 NES 210215 B Self-propelled micromotors b with a reversible braking system are shown. Manganese ions are embedded in microporous silica nanoparticles to catalyse the degradation of the H SB 2 sb O SB 2 sb "fuel" to water and gaseous oxygen. [Extracted from the article]