Micro/nano Fluidic Generator Based On Electrokinetic Phenomena

With the development of nanotechnology,the power consumption of micro/nano electronic devices has dropped to microwatt magnitude,which makes it possible that we can realize the self-powered system by harvesting various environmental energies and converting them into electrical energy.Such self-powered system makes the numerous distributed electronic devices capable of independent,continuous and maintenance-free operation,which has great significance and broad market.The micro/nano fluidic generator based on electrokinetic phenomena,which can convert other forms of energies into electricity through the interaction between fluid and micro/nano materials,has great potential in building self-powered system.In this thesis,we firstly review the developments of electrokinetic phenomena and electrical double layer theory,and introduce various applications based on the screening effect on ions of micro/nano channels.Then,we focus on the theory and development of the micro/nano fluidic generators based on electrokinetic phenomena.Finally,we fabricate several new types of micro/nano fluidic generator that are suitable for harvesting environmental energies and building self-powered system The main results are shown as follows:1.A PDMS-based microfluidic generator is fabricated through soft lithography and the working mechanism of the generator is studied.We have experimentally and theoretically explored the various influence factors of the performance of the generator,which is instructive for optimizing device design and improving the generation performance.Finally,we have demonstrated the great potential of the PDMS-based microfluidic generator for mechanical energy harvesting through practical applications.2.A porous ethanol carbon black film composed of carbon nano particles was synthesized through a simple flame method.After further treatment and packaging,the evaporation-induced nanofluidic generator with an open-circuit voltage of?1 V was obtained,which is of great practical significance.After systematical studies,we have discovered that the evaporation rate is the main influence factor of the generating performance and such electricity generating phenomenon is a kind of electrokinetic phenomenon-based energy conversion,which is caused by the evaporation-induced liquid flow in porous nano carbon materials.Furthermore,we have found that such electricity generating phenomenon is common in various kinds of nano carbon materials.In order to overcome the structural instability of the flame-synthesized device,we developed an all-printed enhanced nanofluidic generator based on nano carbon materials.The all-printed device possesses much better mechanical property,simple operation,improved performance and is easy to scale up.Finally,we successfully lighted an LED directly and electroplated a silver structure using the nano carbon materials based evaporation-induced nanofluidic generators as power source.3.A free-standing carbon film with concrete structure was synthesized,where the interlaced glass micro fibers(GMFs)were tightly surrounded by carbon nano particles,which has significantly enhanced the mechanical property of the porous carbon film and endowed it with good flexibility and tensile properties.Thus evaporation-induced nanofluidic generator based on the free-standing carbon film owns much higher generating performance and could be rolled up to reduce its workspace.The open-circuit voltage and short-circuit current of a generator with the size of 45×400×0.13 mm3 can reach as high as?1 V and?28?A,respectively.Through the degradation of methylene blue(MB),we have promoted the application of nanofluidic generator to degradation of organic waste.