Preparation And Characterization Of Engineered Water Nanostructure And Its Applications In Fashion Material Functional Finishing

Nowadays,the increasing economic and environmental requirements,as well as people’s pursuit of health,safety and comfortable life,promote the continuous development of green and efficient multi-functional finishing methods of textile materials.Some of the traditional functional finishing technologies have unavoidable shortcomings,such as large consumption of water and electricity,expensive equipment,complex manufacturing process,and pollution caused by waste water discharge,all of which undoubtedly cause great difficulties in the real production and application.Optimizing the production process,reducing energy and material consumption,avoiding pollution emissions and achieve low cost will be the ultimate goal in this research field.In addition,due to the impact of global infectious diseases,the emergency protection and arrangement of materials has gradually attracted social attention.How to reduce the risk of medical staff infecting bacteria and microorganisms at work,and how to prevent ordinary consumers from being harmed by various risk factors in outdoor activities are also important development directions in the futureEngineered Water Nanostructure technology(EWNS)is a novel and environmental-friendly technology.This technology is based on the theory of electrostatic atomization.By applying high voltage to the liquid water supplied by the metal capillary,nanoscale water droplets containing electrons and a large number of Reactive Oxygen Species(ROS)can be generated.Some studies have shown that each EWNS structure is tens of nanometers in size and contains a large number of hydroxyl radicals(OH·)and superoxide radicals(O2·-),which are reactive in the chemical oxidation of cellulose and phenolic compounds.At present,this technology has been used in the field of bacteria inactivation and food safety control,but has never been applied in the field of material functional finishing.Relevant studies have shown that the ROS component contained in EWNS have strong chemical activity,and can react with a variety of organic and inorganic substances through hydrogen extraction,addition,substitution,oxidation,etc.,especially for cellulose and phenolic compounds.It has been found that EWNS can change the surface properties of materials,and has different effects on different components of materials.In this study the EWNS technology and its application in functional finishing of textile materials have been mainly studied(1)The EWNS generator with adjustable parameters has been successfully constructed.The current EWNS equipment has some unavoided problems,such as unstable fluid supply,non-controllable parameters and low generation efficiency of electrode.Regarding to the above problems,this study designed and built a novel EWNS generation system with continuous and stable fluid supply,infinitely adjustable parameters,and optimized electrode shape.The continuous liquid supply is achieved by using a micro syringe pump.The controllable parameters are realized by adjusting the liquid supply flow rate,DC voltage value,needle plate spacing,needle tip distance to meet the experimental needs.A new type of four-needle induction electrode plate is proposed in the research of mechanics related theory.Through simulation and experimental research,it is found that the electrode plate has a higher maximum electric field strength value than the ordinary circular induction electrode plate,thus it has a higher EWNS Preparation efficiency.Considering the actual production demand,based on the single needle EWNS generator,the optimal needle tip distance of the double needle EWNS generator is studied.Through the combination of software simulation and experimental verification,the optimal needle tip distance of the double needle EWNS generator is finally determined(2)The optimum parameters for the preparation of EWNS were determined.The characterization of EWNS were conducted.The normal working state of EWNS was preliminarily judged according to the stable current loop,stable Taylor cone,stable corona discharge and no visible droplets on PET film.By means of experimental study,two groups of parameters which can stably generate EWNS are determined,which are[1.2μL/min,-5 kV,0.5 cm]and[1.2μL/min,-6.8 kV,1 cm].Based on the contructed equipment,the micro-scale characterization of EWNS was firstly conducted.The main parameters for micro-scale characterization were the particle size of EWNS and the content of free radicals.The average particle size of EWNS can be obtained by spraying EWNS on the fresh mica and extracting the image parameters by using AFM.The characterization of free radicals is mainly carried out by electron spin resonance(ESR).The EWNS generator is applied to the DMPO agent to make the free radicals react with DMPO,and the signal of the intermediate products can be captured by the instrument.The results showed that the particle sizes of EWNS produced by the two groups of parameters were very close,which were(36.34±7.11)nm and(37.11±3.44)nm,respectively,but the concentration of two free radicals produced by[1.2μL/min,-5 kV,0.5 cm]was higher than[1.2μL/min,-6.8 kV,1 cm].Therefore,the following parameters[1.2μL/min,-5 kV,0.5 cm]are selected to explore the application of EWNS in textile materials.In addition,considering the test environment of ordinary laboratory,a macro characterization method characterized by white spots on PET film was established.The results show that only in the normal working state of the EWNS device,the complete round spot pattern can be produced on the surface of PET film,so it can be used as the method to characterize the existence of EWNS.(3)The application and mechanism of EWNS in antibacterial finishing of clothing materials were investigated.In this study,cotton fabric was selected for the research,and the antibacterial activity of EWNS treated cotton fabric against Gram-negative bacteria(Escherichia coli)and Gram-positive bacteria(Staphylococcus aureus)was explored.The results showed that the antibacterial rates of EWNS treated fabric for 1 h against Escherichia coli and Staphylococcus aureus were 99.9%and 99.0%,respectively,while that of untreated cotton fabric against both bacteria was 0%.After 5 h of EWNS treatment,the antibacterial activity of the fabric against two kinds of bacteria can still maintain above 99.0%after 12 h,24 h,36 h,48 h and 72h.The results show that the cotton fabric treated by EWNS has good antibacterial property and can be maintained for a long time.After EWNS treatment,the cotton fabric can keep antibacterial properties for a long time.The analysis shows that this may be due to the deaffinity reaction between OH· in EWNS and fiber molecules,and the water molecules produced attach to the surface of cotton fibers to form a hydrated layer,which can effectively block the adhesion of bacteria.At the same time,ROS may interact with cellulose.The reaction of the phenolic substance causes the position or number of the hydroxyl group in the phenolic substance to change and the chemical reactions of these phenols can be activated,thereby improving the antibacterial property of the fabric(4)The application and mechanism of EWNS in hydrophilic finishing of clothing materials were investigated.Polyester fabric is selected for the research.The results show that the original polyester fabric without EWNS treatment has high hydrophobicity,and its contact angle can reach 113°,while the hydrophilicity of the treated polyester fabric is significantly improved,so it is difficult to measure the stable contact angle(instantaneous contact angle is 43°).The wetting time of treated polyester fabric was studied.It was found that the wetting time of EWN S treated polyester fabric was significantly lower than that of untreated polyester fabric,and the wetting speed increased with the increase of EWNS treatment time.After standing for 72 h,the polyester fabric treated for 7 h still has good hydrophilicity,which indicates that EWNS can effectively improve the hydrophilicity of polyester fabric and has good durability.Through FTIR testing,it is found that the main reason why EWNS can improve the hydrophilic property of polyester fabric is that the ROS in EWNS can react with polyester,resulting in polar functional groups on the surface of treated polyester material,thus increasing the surface hydrophilicity(5)The application and mechanism of EWNS in anti-pilling finishing of clothing materials were investigated.Wool fabric is selected for the research.The results show that the anti-pilling performance of wool fabrics treated with EWNS at different times were improved in varying degrees,and the evaluation grade increased with the increase of treatment time.The wool fabric treated with EWNS for 7 h has nearly two grades of fuzzing and pilling evaluation,and the wool fabric treated for 1 h has more than 0.5 grades.However,the anti-pilling durability of wool fabric treated with EWNS is not good.The anti-pilling performance of wool fabric treated with EWNS for 7 h and placed for 6 h has not been improved.This indicates that the main reason for the improvement of anti-pilling performance of EWNS is that the friction coefficient of wool fiber is reduced by the nanoscale droplets attached to the fiber surface.In this case,these nano droplets play a role equivalent to the lubricant,making the slippage between the wool fibers easier and not prone to entanglement,which reduces the tendency of the fabric to fluff and pilling.When placed for a period of time,the droplets on the fiber disappear,so it cannot work anymore(6)The influence of EWNS on the wearabilities of textile materials was analyzed,and the environmental protection of EWNS was also evaluated.It was found that the breaking strength,elongation at break and chromatic aberration of cotton,polyester and wool fibers have not been influenced significantly even after long-time treatment,which indicated that EWNS would not affect the mechanical strength and appearance properties of textile materials.Through the analysis of chemical use,calculation of power consumption and water consumption,it is found that EWNS technology only uses high-purity water in textile finishing,does not involve the use of other chemicals,and will not produce other by-products and cause environmental pollution.This technology is a dry treatment technology.After treatment,there is no need for secondary treatment,It has better technical advantages compared with the traditional wet treatment method.In addition,the theoretical calculation shows that 1.26 L of water and 1.75 kW·h of electricity is needed for every 1 m2 of fabric treated with EWNs for a long time(7 h).Although this value can not be compared with the existing related technologies,the results can provide theoretical support for the future study.In conclusion,this technology has good environmental protection potentialIn general,the optimized electrode proposed in this project can provide a new way for the development of instruments and equipment in the field of electrostatic atomization.At the same time,the method to determine the tip distance of multi needle EWNS device also provides a theoretical basis for its practical applicatio.It is the first time that the EWNS technology is applied to the textile field,which creates the possibility of realizing a new and environmental friendly multi-functional finishing method of textile materials,and opens up a new research direction for the follow-up research and development of green and sustainable techniques.