Doctoral thesis defence
Electrospinning Core-Sheath Functional Fibers
Wearable technology in general has increasingly gained interest in the last few decades and textile incorporated with functional component is one form of it. There are multiple ways to produce polymer fibers on both laboratory and industrial scales, and one of them is core–sheath electrospinning, which is a powerful method for producing advanced composite fibers. Liquid crystals (LCs), are materials that readily exhibit optical response to fluctuations and change in their immediate environment. By incorporating LC within polymer fibers through the electrospinning, it is possible to create responsive LC-polymer fiber mats. However, incorporating a functional core has proven challenging for certain combinations of materials. This thesis explores and addresses some of the concerns involved in the coaxial electrospinning of fibers incorporating LCs from several standpoints.
Firstly, the effect of solvents on the electrospinning process was systematically studied. Following this, an optimum viscosity with pure and mixed solvents for successful electrospinning was identified and uniform fibers with different solvent combinations was produced. Using the knowledge gained, core-sheath electrospinning with LC as the core was carried out. One of the key findings of this work was, the identification of a suitable means to reduce the interfacial tension between the core and sheath fluid to prevent breakup of the jet and produce uniformly filled fibers, while at the same time avoiding complete mixing between core and sheath.
These findings can be applied to any combination of core and sheath materials and should appeal to large community of researchers. Eventually, to achieve the durability of the LC-functionalized electrospun fiber mats for use in wearable technology, the sheath polymer of the fibers was crosslinked after spinning. The resultant crosslinked fibers were easily manipulated by hand and even fully immersed in water without dissolving and without losing their functional LC core.
Docotral defence committee
- Chairman: Dr. Anupam Sengupta, Assistant Professor, Université du Luxembourg
- Dr Giusy Scalia, ADR, Université du Luxembourg
- Dr Maria-Helena Godinho, Associate Professor, Universidade Nova de Lisboa
- Dr Margaret Frey, Professor, Cornell University
- Dr Jan Lagerwall, Professor, dissertation supervisor, Université du Luxembourg