Designing,Fabrication And Research About Propulsion Mechanism Of Several Novel Chemically Powered Micro/Nano-Motors

Micro/nano-motors are micro/nanoscale energy-converting devices,which are capable of transforming the biological,physical or chemical energy from themselves or environment into mechanical energy and performing specific movement.In this thesis,several self-propelled micro/nano-motors were designed and fabricated based on template directed electrodepositing,physical vapor deposition.The fabricating method,characteristic,concentrating analysis and mechanism of catalytic reaction occurred on the micro/nano-motors were studied preliminarily.In addition,the speeds,motion manners and propulsion mechanism were also discussed.There are nine chapters in this thesis:In chapter 1,the review of micro/nanomotors were introduced in detail.Finally,the basis,contents and significances of this research were introduced.In chapter 2,the new Au-Fe/Ni nanomotors have been fabricated through TDEP,the Cu,pre-plated Au,Au and Fe/Ni layer were deposited into the AAO template,then the AAO template and Cu layer were dissolved and Au-Fe/Ni nanomotor were released.The average length of these nanomotors was about 6 ?m,and the average diameter about 300 nm.The composition of Fe/Ni alloy was in the range of Fe53Ni47 to Fe60Ni40.In chapter 3,three motion manners of Au-Fe/Ni nanomotors-rotation,linear motion along the axis,rotation and axial motion alternately were observed in the mixed fuel composed of H2O2 and N2H4,and the cause of different manners was dissussed.The dramatic acceleration of Au-Fe/Ni nanomotors was 150 body-lengths per second.The speed of Au-Fe/Ni nanomotors was strongly depended on the composition of Fe/Ni alloy segment and the mixed fuel.As born with magnetism,the Au-Fe/Ni alloy nanomotors also can be guided by the magnetic force.In chapter 4,the mechanism of catalytic reaction occurred on the nanomotors was studied.It was found that the oxidation of H2O2 can also be facilitated by hydrazine in mixed fuels,resulting in oxygen bubbles propelling Au-Fe/Ni nanomotors forward.Moreover,the speed of Au-Fe/Ni nanomotors was not positively correlated with the mixed potential difference between the composite metal pair,which had not been found in similar self-electrophoresis propelled nanomotors.In chapter 5,the Au-Fe/Ni/(Mo/Co)alloy microsphere motors(AMSM),having an average diameter of 7?9 ?m,were fabricated though physical vapor deposition(PVD).Via co-catalytic decomposing reaction in the mixed fuel of hydrogen peroxide and hydrazine,the ejection of oxygen bubbles generated from the Fe/Ni/(Mo/Co)alloy hemisphere,and provides a powerful directional propulsion.The AMSM's moving ability closely depends upon the thickness of Au sputtered layer,the content of mixed fuel,the composition of alloy.The AMSM can move as fast as 548.63 ?m/s(ca.64 body-lengths/s),which also can be guided by the magnetic force.In chapter 6,the Cu-Zn microsphere motors were fabricated though PVD method.While the pH? 1,the fabricated Cu-Zn micromotors can be driven by the H2 bubble produced though the reaction of Zn and H+ in the surface of Zn hemisphere,the average speed is 12.2 ?m/s.The motion can last for more than 15min.In chapter 7,the hollow Au-g-C3N4 sphere(Au-HCNS)nanomotors were fabricated through PVD method.The Au-HCNS nanomotors,with a diameter of about 300 nm,can photocatalyze the 5%H2O2 to produce O2 bubbles in visible light and move in the mixed solution of H2O2 and N2H4,the average speed is 12.2 ?m/s(as 40.6 body-lengths/s).In chapter 8,Pt-Carbon fiber(Pt-CF)rod-shaped micromotors were fabricated based on the principle of bipolar electrodeposition.A cutting method was employed to prepare carbon fiber segments with similar length.The micromotors' diameter is 6.4±0.2 ?m,the length is 102 ±5 ?m.The velocity of Pt-CF in 20%H2O2 solution isabout 1800 ?m/s.In chapter 9,a rapid catalase/Au-Carbon fiber(CAT/Au-CF)enzyme-catalyzed micromotors were synthesized by Au bipolar electrodeposition and CAT modification.The micromotor could move predominantly in 0.1%H2O2,the speed is up to 40 ?m/s,i.e.400 ?m/s per 1%fuel concentration.Such a low fuel concentration represents a tens-fold decrease in the level required for movement of common catalytic micro/nano-motors,and the ratio of velocity to fuel concentration is largely compared with most of other micro/nano-motors powered by H2O2.