Morphology Control And Self-Driving Behavior Of Flask-Like Janus Colloidal Particle

Janus nanoparticles,as a strictly partitioned composite,can achieve multifunctional coupling and intelligent response.In this paper,flask-like silica-based anisotropic Janus micro-nanoparticles were designed and prepared by applying microemulsion templates and silane precursors to initiate interfacial sol-gel reactions,and their morphology modulation and self-driven behavior were investigated,mainly as follows:（1）A hydroalcoholic reverse microemulsion system was constructed,and flask-shaped Janus particles with different compositions on the inner and outer surfaces were successfully prepared by inducing the aggregation of two silane precursors with different hydrophilicity,1,2-di（triethoxysilyl）ethane（BTEE）and 3-mercaptopropyltriethoxysilane（MPTES）,at the water-oil interface,and further replicating the droplet shape and Brownian motion trajectory using the sol-gel process.The neck length and chemical structure of the Janus particles could be flexibly adjusted by using two silane precursor feeding ratios and feeding intervals.12 h of BTEE reaction followed by 24 h of MPTES reaction resulted in serpentine Janus particles with an elemental gradient distribution.The type of silane precursor had an important influence on the morphological changes of the Janus particles,and morphologically rich Janus colloidal particles were synthesized using different silane precursors.（2）Noble metal-loaded flask Janus colloidal composite particles（FJPs@Pt and FJPs@Au）were obtained by functionalizing flask Janus particles using a selective in situ growth strategy.FJPs@Pt can be used as colloidal self-driven motors.The visualization and quantification of the motion trajectory of the colloidal motor by optical microscopy and mathematical statistics showed that the neck length is an important influence on the movement speed of the colloidal motor.Its neck provides the Janus colloidal motor with well-defined directionality and tunable velocity,the maximum diffusion coefficient of FJPs@Pt colloidal motors up to 18.2μm² s^-1,enabling self-driven behavior beyond Brownian motion.