Reserch On Synthesis And Chemically Self-propelled Behavior Of Heterodimer Nanoparticles

The active particles with self-propelled motion,which are also called colloidal motors,are expected to provide innovative applications in environmental,biomedical and other fields.The related research has attracted much attention in recent years.However,the present chemically self-powered colloidal motors have the problems of large size(the research on submicron colloidal motors is still in its infancy),limited structure types(such as spherical,rod-shaped,conical and other common structure),poor driving controllability,low efficiency of preparation,etc.Aiming at these,the research on synthesis and chemically self-propelled behavior of heterodimer nanoparticles(NPs)was carried out in this dissertation based on material systems of noble metals,MoS2,etc.The main content concludes designing new structure,mass-producing colloidal motors,revealing the growth process and mechanism of heterodimer NPs,and exploring the phenomena and laws of self-propelled motion of dimer motors.The main innovative achievements are presented as follows.(1)Proposed the idea of preparing spherical MoS2 particles based on laser ablation in liquid.Spherical MoS2NPs with smooth surface and onion-like crystal structure were prepared by laser ablating MoS2 target in water.A mechanism based on laser-induced molten MoS2 droplet formation and droplet radial solidification/oriented growth was proposed to reveal the onion-structured formation process of such spherical particles.Spherical MoS2 NPs obtained aim to provide a component unit for preparation of dimer NPs.(2)Developed a route to mass-producing dimer NPs in solution phase.The dimer NPs(Au-MoS2)composed of hemispherical Au particles and MoS2 nanospheres,and dimer NPs(Ag-MoS2)composed of polyhedral Ag nanocrystals and MoS2 nanospheres were mass-produced successfully by dropping appropriate amount of HAuCl4,and AgNO3 solutions into MoS2 nanospheres-contained colloidal solution,respectively.The mechanisms based on Au NPs' aggregation and Ag NPs'aggregation/oriented-connection growth were proposed to reveal the formation of Au-MoS2 and Ag-MoS2 dimer particles.These lay the material foundation of motor research of self-propelled behavior.(3)Confirmed that the Ag-MoS2 dimer NPs showed motor behavior.It is found that Ag-MoS2 dimer NPs have typical characteristics of self-propelled motor motion in H2O2 fuel-contained solution,such as obvious directional motion,the dependence of their motion speed on H2O2 concentration,and so on.It is confirmed that Ag-MoS2 dimer NPs are a new type of colloidal motors.(4)Found 'abnormal' motion behavior of Pt-SiO2 dimer motors.The quasi-circular motion and the motion orientation towards Pt end of Pt-SiO2 dimer motors were observed.These are both obviously different from those of the traditional Pt-SiO2 Janus spherical motors.The correlation between the motion behavior and the dimer structure was further revealed.This work deepens the understanding of the self-diffusiophoresis driven motor motion.This dissertation provides a simple mass-producing method to construction of heterodimer structural nanomotors,reveals their formation mechanism at the same time,and preliminarily shows their motion characteristics,which lays a foundation for further study on individual motor motion and group behavior of dimer colloidal nanomotors.This dissertation provides a reference for developing new structural motors and motor applications of required corresponding motion behavior.