Preparation of finish on cellulose fibres with nanoparticles of titanium dioxide, silver and graphitic carbon nitride with antimicrobial and photocatalytic performance

V preteklih letih se je uporaba nanotehnologije pri načrtovanju tekstilij že dodobra uveljavila. Velik potencial med drugim kažejo fotokatalizatorji, kot sta titanov dioksid in grafitni ogljikov nitrid, ki prinašajo sodoben način odstranjevanja organskih onesnaževal, in kovinski nanodelci, kot so nanodelci srebra, ki omogočajo učinkovito zaščito pred mikrobi. Raziskovalci intenzivno preučujejo, kako še povečati učinkovitost tekstilnih apretur iz teh nanomaterialov, obenem pa poenostaviti njihovo pripravo in jih narediti okolju in človekovemu zdravju neškodljive. V magistrskem delu je bila uspešno pripravljena in analizirana trikomponentna nanokompozitna apretura na celuloznih vlaknih z dobro protimikrobno in fotokatalitično aktivnostjo, sestavljena iz srebra, titanovega dioksida in grafitnega ogljikovega nitrida. Lastnosti tako obdelanih bombažnih vzorcev so bile primerjane z neobdelanim bombažem in z vzorci, na katere so bile nanesene enokomponentne in dvokomponentne apreture. Rezultati analiz morfologije z rentgenskim praškovnim difraktometrom in vrstičnim elektronskim mikroskopom so pokazali, da je titanov dioksid oplaščil celulozna vlakna, na njih pa so se tvorile strukture srebra in grafitnega ogljikovega nitrida nanometrskih velikosti. Pri sprektrofotometričnem preučevanju optičnih lastnosti, se je izkazalo, da so posamezne komponente med seboj kompatibilne in učinkovito zmanjšajo energijo prepovedanega pasu v hetero-spoju. Za vzbujanje elektronov je bilo zato pri trikomponentni apreturi potrebne najmanj energije, kar se je pokazalo tudi pri fotokatalitskem samoočiščenju madežev kave. Takšna apretura je bombažni tkanini dodala še odlično funkcijo zaščite pred ultravijoličnim sevanjem. Testirane so bile še protimikrobne lastnosti obdelanih vzorcev. Izkazalo se je, da je najboljšo zaščito tako pred po Gramu negativnimi in po Gramu pozitivnimi bakterijami kot tudi pred virusi predstavljala ravno obdelava celuloznih vlaken s trikomponentno apreturo. Zelo dobro zaščito je predstavljala tudi dvokomponentna apretura, sestavljena iz srebra in titanovega dioksida. Apretiranje tkanine pa ni povečalo njene citotoksičnosti. Termične in mehanske lastnosti tkanine se zaradi obdelave z apreturami niso spremenile v meri, da bi vplivale na njeno uporabno vrednost. Hetero-spoj med titanovim dioksidom in grafitnim ogljikovim nitridom ter hkratna prisotnost nanodelcev srebra sta povzročila izboljšano fotokatalitično delovanje apretiranih celuloznih vlaken. Koncentracija komponent je bila dovolj velika za protimikrobno delovanje, a dovolj majhna, da ni prišlo do citotoksičnih vplivov. Takšna apretura na celuloznih vlaknih je bila prvič preučevana in izkazalo se je, da obeta učinkovito trajnostno rešitev za funkcionalizacijo tekstilij.Nanotechnology in textiles has already been well explored and nanomaterials show a great potential. Especially photocatalysts, such as titanium dioxide and graphitic carbon nitride, prospering in photodegradation of organic pollutants, and metal nanoparticles, such as silver nanoparticles with antimicrobial activity, look promising. There is a lot of research concerning enhancement of textile coatings made of these nanomaterials, coating preparation simplification. It is also a question how to fabricate nontoxic coatings, harmless for the environment. In the master’s thesis, ternary nanocomposite for coating cellulose fibres, made of silver, titanium dioxide and graphitic carbon nitride, was successfully prepared. It has been shown that it exhibited great antimicrobial and photocatalytic activity. Its properties were compared to pristine cotton, fabric, coated with binary nanocomposites, and fabric, coated with single components only. Morphology analysis was obtained with x-ray diffraction and scanning electron microscope. It showed that titanium dioxide created film on fibres. On the other hand, silver and graphitic carbon nitride formed nanostructures. Spectrophotometric analysis of optical properties showed compatibility between components of coating which consequence in narrower band gap energy. That’s why less energy is needed for electron excitation in case of ternary coating, which was shown in coffee stains photodegradation experiment. Same coating made cotton fabric also more protective against ultraviolet radiation. Furthermore, coated specimens were tested for antimicrobial properties. It was shown that ternary coating gives the best protection against Gram-negative and Gram-positive bacteria and against viruses. Very good protection showed also binary coating, made of silver and titanium dioxide. Coated specimens did not show to be cytotoxic. Experiments proved that thermic and mechanic properties of coated fabric haven’t changed to such a great extent that coating would affect usable value of fabric. The formation of the heterojunction between titanium dioxide and graphitic carbon nitride, combined with the load of silver nanoparticles, enhanced photocatalytic performance of coated cellulose fibres. Concentration of coating components was high enough for antimicrobial activity, but low enough that no cytotoxic effects occurred. Cotton fabric, coated with this ternary nanocomposite was studied for the first time and has proven to be an effective sustainable solution for the textile functionalization