| Multifunctional textiles are fast-growing technologies and the achievement will improve human's living standard significantly.They have been employed in protecting humans from environmental hazards and threats such as for firefighter apparel,medical,and military garments.In most cases,functional textiles meet a wel-defined set of requirements such as chemicals,fire,water,oils,gases,and pollution.In general,there are very few original fabrics meeting these virous characteristics.Functionalization of the fabrics has been developed to fulfill the requirements.Traditional wet chemical functionalization methods of textiles meet great environmental chal enges due to their complex and long-term operations and the use of toxic compounds.Up to now,non-thermal or low-temperature plasmas are one of the most suitable and environmental methods to apply to surface functionalization of heatsensitive textile materials.It is also a flexible technology for improvement of the treatment durability,as the textile surface can be treated and introduced with a wide range of chemically active functions to improve wettability and adhesion etc.Plasma treatment performance and durability depends on the kinds of the substrate and the operational conditions of the treatment.After treated only by O2 or Ar or N2,the fabric usual y becomes hydrophilic immediately.However,after storage for some time,the performance becomes declined or disappeared because of the “aging effect” of the short functional groups.Furthermore,most textiles would be subject to repeated washing during their lives;therefore,the durable multifunctional of fabrics against laundry washing is significantly important.In this thesis,the above critical problems in plasma treatment and functionalization of textiles are typically examined and discussed,especially for improving their durability by graft polymerization and selective etching.Considering that the surfaces of the most-used Poly-Phenylene Terephthalamide(PPTA)and polyethylene terephthalate(PET)fibers are smooth and the adhesion of the fibers with their functional copolymers is low,these two fabrics are used in this functio na l durability study.Plasma treatment and surface physical and chemical changes of the fabric are investigated for the durable hydrophobicity with C6(6 carbon atoms short chain of perfluoralkyl methlacrylate copolymer emulsion)and flame-resistant PPTA aramid fabric.PET fabric with mixed Ti O2 nanoparticles into the fiber is used and the selective etching for organic/inorganic components of PET/Ti O2 is successfully achieved.Durable hydrophobicity and more efficient antibacterial of PET/Ti O2 are obtained and the mechanism is discussed.The fabrication method based on plasma graft polymerization and selective etching has proven to be appealing due to greatlyimproved durability and its applicability on functional polymeric fabrics.The main research results obtained are summarized as follows:?.Durable superomniphobic surfaces are desirable for their practical applicatio ns,including self-cleaning,non-fouling,protective clothing,and liquids' separation.Fluorine C6 is an ecological alternative to C8(eight CF2 groups)fluorinated compounds.The plasma-induced polymerization of environmentally friendly C6 from a perfluoralkyl methlacrylate copolymer emulsion,AG-E081,was performed,and a durable omniphobic aramid fabric was achieved.The fabric became water and oil repellent with an extremely high-water contact angle of 180°.As tested by the water spray “The American Association of Textile Chemists and Colorists(AATCC)” test and hydrocarbon resistance test,the plasma treated and coated aramid fabric gained 100°(ISO 5)and grade number 4,respectively.Furthermore,the fabrics also showed significantly improved washing durability after 10 washing cycles.By scanning electron microscopy(SEM),Fourier-transform infrared spectroscopy(FTIR),and x-ray photoelectron spectroscopy(XPS)tests,it is indicated that the durable superomniphobicity can be attributed to the roughness and activation of the aramid surface by the plasma pre-treatment,which induces more adsorption and chemical graft of the C6 copolymer.?.Furthermore,a durable flame-resistant and ultra-hydrophobic phosphorus-fluor ide coating on aramid fabrics was achieved by plasma-induced graft polymerizat io n.The aramid fabrics were activated and roughed through low-pressure plasma firstly,followed by a sequential coating of a phosphorus-fluoride emulsion copolymer mixture.When potentially exposed to flame or water,such a surface produces a dual effect in which it is intumescent and waterproof,successfully giving the coated fabrics flame-resistant ultra-hydrophobic bifunctional properties.After 10 repeatable washing cycles,the treated fabrics did not lose their flame resistance and superhydrophobicity,suggesting future applications as advanced multifunctional textiles.Its char length was less than 1 cm with no measurable after-flame or after-glow times,and its static water contact angle remained stable above 170°.However,the untreated control sample could not extinguish the fire with a damage length of 10.6 cm and a water contact angle of 100°.All the results indicate that plasma-reactive polar groups interact with phosphorus or fluorine copolymers,leading to an increased relative atom ratio P and F through Energy- Dispersive Spectrometer(EDS)spectra,and XPS analysis,which inhibits the flammability and wettability.?.Also,antibacterial functional PET/Ti O2 fabric has been prepared in an efficie nt,one-step plasma selective etching process that increased the surface roughness and exposed Ti O2 micro/nanoparticles inside the fiber matrix to the surface.The improved antibacterial activity was assessed under fluorescent light(< 830 nm)and UV lamp(< 365 nm)irradiation against Escherichia coli and Staphylococcus aureus.EDS spectra and XPS analysis showed the increased relative atom ratios of O and Ti element.Under different radiations,the enhanced antibacterial activit y resulted in inhabitation zones of(1 and 1.35 mm)untreated and(1.55 and 2.61 mm)treated,and bacteria reduction of 80% compared to 40% for the untreated.The plasma etching process offered a new controllable path to innovate synthetic polymer fabrics for medical apparel.?.Finally,commercial deluster polyethylene terephthalate(PET/Ti O2)fabric treated by radio frequency(13.56 MHz)plasma and further coated with perfluoroa lk yl methacrylate copolymer C6 displays much highly durable hydrophobicity and oleophobicity.After 10 washing cycles,the as-prepared PET/Ti O2 fabric had a water contact angle above 170°,a water spray rating of 80(ISO 3),and oil resistance ratings B(grade 4)that were two levels higher than the untreated and C6-coated PET/Ti O2 fabric.The organic component PET was more prone to etching than Ti O2,which created a waviness structure and exposed prominent Ti O2 nanoparticles on the PET fiber surface.The relative atom ratio O and Ti increased through EDS and XPS analysis.This result indicates that the exposure of Ti O2 and the introduction of reactive polar groups such as O=C-O on the fiber surface contributed to react with C6 and improved the washing durability.In general,such coating technology may provide a simple benign technique for constructing materials with physicochemical function properties.This study found that plasma graft polymerization and selective etching approaches on PPTA aramid,as well as delustered PET/Ti O2,enhanced coating adhesion and resulted in major improvements in durable water and oil repellency,as well as efficient flame resistance,and antibacterial applications.Nano/micro surface functionalization techniques at various scales each have their own set of advantages for various applications.As a result,the work done here will provide a strong foundatio n for future scientific research and business opportunities in the textile industry. |
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