Study On The Mechanism Of Directional Liquid Transport Driven By Dual-angle Structure In Goose Feather Fiber And Its Bioinspired Design

The directional transport of liquids is widely existing in the natural world,which is widely used in oilwater separation,drug delivery,fog collection and micro fluidic chip.The researchers have found that the gradient play an extremely important role in directional transport process,and developed the way based on the thermal gradient,light gradient,chemical gradient and structure gradient realized the directional transport of liquids has been applied in many areas.However,the directional transport process based on a thermal gradient and light gradient requires external energy input,and the directional transport process based on chemical gradient can’t be used for a long time.The structure gradient is mainly relying on its inherent structural asymmetry to realize liquid directional transport,on the one hand,does not need external energy input,on the other hand to be able to keep for a long time directed transport capacity.It’s kind of superior unpowered directional transport strategy.The common structure gradient design inspiration comes from the cacti conical acupuncture structure and the spider silk periodic spindle structure.However,with the elongation of the cone,the Laplace pressure will be lost due to the liquid is difficult to cover the cone for the gradual increase of the diameter in the cone,so the directional transport will not be sustained.In the bionic spider silk structure,the droplets cannot be transported across the spindle structure itself,and it is hard to realize the long distance directional transport.The key to overcoming the shortage of bionic conical structure and periodic spindle structure model in transport distance is developing the new structure model driven system to realize the liquid directional transport in long distance without external energy input.There is an obvious asymmetry structure in feather fiber,if the asymmetry structure is introduced into the liquid directional transport system,which is expected to be a new type of liquid directional transport driving structure.Based on the above ideas,in this dissertation,we carefully characterize the goose feather fibers and more than 10 kinds of feather fiber structure,found the goose feather fiber’s dual structure angle,and liquids directional transport phenomena.Explore the mechanism of dual angle structure in the process of liquids directional transport,and expounds that the asymmetric capillary force caused by anisotropy of goose feather fiber structure is the root of directional transport.Then through mechanical extrusion method and 3D printing technology to create the structure of the bionic the dual angle,reveals the control action by the structure of coincidence degree on the directional transport process.It will be providing a new technical solution and research methods for the development of liquid directional transport based on this new anisotropic structure,and play an active role in promoting the research and application of unpowered liquid transport.The main contents of this dissertation are as follows:(1)Study on directional liquid transport driven by feather fiber structure.Kaifeng local poultry white goose feather fibers as experimental material and the directional transport of various liquids was found.The structure of feather fiber were carefully characterized,and the dual angle structure of anisotropy on feather fiber were found.After in situ observation,directional transport phenomena observed liquid ’capillary relay’ behavior,constructed the model of liquid transport on the structure,put forward the dual angle ’capillary relay’ produced the synergy to realize the liquid directional transport,and on the theoretical calculation is verified.The polydimethylsiloxane(PDMS)surface with a feather fiber structure was obtained by two complex methods,successful realization the liquid directional transport.(2)Bionic design based on dual angle ’capillary relay’ directional transport liquid.On the basis of ’capillary relay’,in the third chapter we designed a continuous three-pyramid ’groove’ structure,used the capillary force between the inner corners of the ’groove’ to complete the directional transport of the liquid.Through the way of mechanical extrusion,the ’groove’ structure is constructed on the surface of polyethylene(PE)and the directional transport of liquid is successfully realized.Although there are excellent directional transport effects,but the samples prepared by this method are crude and difficult to quantify the structural parameters.In order to more accurate control of the structural characteristics,we use the 3D printing technology prepare the directional transport structure,and regulation the degree of structural coincidence λ to investigate the influence in the directional transport process.The results show that,for a certain liquid,when the structure has a small degree of structural coincidence λ is easier to achieve directional transport,after λ increasing to a certain extent,the directional transport capacity is lost.