Razvoj nanovlaken z visokim deležem hitosana z uporabo elektrostatskega sukanja

Perša, Lara (author), Zupančič, Špela (mentor)

Polimerna nanovlakna predstavljajo enega izmed najsodobnejših nanomaterialov, ki so v zadnjih dveh desetletjih postala osrednji predmet mnogih znanstvenih raziskav. Nanovlakna lahko izdelamo iz številnih polimerov, med katere prištevamo tudi hitosan. Hitosan je naravni polimer, ki izkazuje biokompatibilnost, netoksičnost in biorazgradljivost, zaradi katerih je primeren za uporabo v biomedicinske namene. Namen diplomske naloge je bil optimizirati postopek elektrostatskega sukanja tako, da bi izdelali visokokakovostna nanovlakna brez vozlov in s čim višjim možnim deležem hitosana. Da bi olajšali nastanek nanovlaken, smo raztopini dodali kopolimer polietilenoksid. Zasnovali smo poskuse, s katerimi smo poglobili naše razumevanje vpliva različnih spremenljivk, kot so sestava raztopine, procesni parametri in dejavniki okolja, na morfologijo in premer izdelanih nanovlaken. Povprečni premer in morfologijo nanovlaken smo vrednotili z vrstično elektronsko mikroskopijo. Elektrostatsko smo sukali raztopine hitosana in polietilenoksida v masnih razmerjih 50/50, 60/40, 70/30, 80/20 in 90/10. Ugotovili smo, da se s povečevanjem deleža hitosana pojavlja čedalje več prekinitev postopka elektrostatskega sukanja, kar vodi v deformacijo nanovlaken. Nepravilnosti, kot so vozli, zlepljanje vlaken, prekinitve curka in polimerni madeži, so razvidni iz slik, posnetih z vrstičnim elektronskim mikroskopom. Stabilizacijo curka in neprekinjeno tvorbo vlaken smo dosegli s pripravo raztopine z dodatkom polietilenoksida z molekulsko maso 4 MDa, z dodatkom 0,1–2,0 % (m/m) površinsko aktivnih snovi v polimerno raztopino in s povečanjem napetosti na 25 kV. Ugotovili smo, da je za neprekinjen postopek nujno, da sta temperatura in relativna vlažnost v komori stalna. Uspešno smo izdelali nanovlakna s povprečnim premerom 59–179 nm. Ker pa na proces elektrostatskega sukanja vplivajo številni znani kot tudi neznani dejavniki, katerih medsebojna povezanost kljub številnim raziskavam še ni popolnoma razjasnjena, je ponovljivost procesa izdelave nanovlaken enakomernih oblik težavna.

• Language: Slovenian
• Keywords: elektrostatsko sukanje, hitosan, nanotehnologija, nanovlakna, polietilenoksid
• Work type: Bachelor thesis/paper
• Organization: FFA - Faculty of Pharmacy
• Year: 2021
• PID: 20.500.12556/RUL-129189
• Publication date in RUL: 28.08.2021

Secondary language

• Language: English
• Title: Development of nanofibers with high content of chitosan by electrospinning

Abstract

Polymer nanofibers present cutting-edge nanomaterials and have in the past two decades become the centre of ongoing scientific research in this field. Nanofibers can be made from many polymers, including chitosan. Chitosan is a natural polymer that exhibits favourable characteristics, such as biocompatibility, non-toxicity and biodegradability, making it suitable for biomedical use. However, the production of chitosan nanofibers can be challenging. The purpose of the thesis was to optimize the process of electrospinning to produce high-quality, beadless nanofibers with the highest possible chitosan content. To enhance the spinnability of the solution, polyethylene oxide was introduced. We designed experiments to deepen our understanding of the influence of different variables on the morphology and diameter of the nanofibers. The influence of solution properties, processing parameters and ambient conditions were investigated. The average diameter and morphology of the nanofibers were evaluated by scanning electron microscopy. Chitosan/polyethylene oxide blends with a mass ratio of 50/50, 60/40, 70/30, 80/20 and 90/10 were electrospun. We found that increasing chitosan content leads to more interruptions of the electrospinning process, resulting in deformation of the obtained nanofibers. Formation of undesirable beads, fiber–fiber bonding, jet breakage, and polymer stains could be observed in the SEM images. Jet stabilization and continuous fiber formation were achieved by using polyethylene oxide with a molecular weight of 4 MDa, addition of 0.1–2.0% (m/m) surfactants to the polymer solutions and increase of the voltage to 25 kV. We found that constant temperature and relative humidity inside the chamber were essential for the continuity of the process. We successfully prepared nanofibers with the average diameter of 59–179 nm. However, since the process of electrospinning is influenced by many known as well as unknown factors, the interconnections of which are yet to be fully clarified, the repeatability of producing uniform nanofibers remains challenging.

• Keywords: electrospinning, chitosan, nanotechnology, nanofibers, polyethylene oxide