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Twisted nylon 6 nanofibre yarns containing microencapsulated phase change materials (MPCMs) were fabricated via electrospinning to prepare thermal regulating nanofibre yarns. Electrospun nanofibre yarns with different contents of MPCMs including 0.375, 0.75, 1.5 and 3 wt% were prepared. The surface morphology, crystallisation and thermal properties of the yarn samples were characterised by scanning electron microscopy (SEM) and differential scanning calorimetry, respectively. SEM results showed that electrospun composite fibres and yarns had good morphology with smooth surface and the MPCMs were randomly distributed on the composite yarn surface, inside the nanofibres and between the fibres in the yarn structure. Additionally, the SEM results suggested that the average diameters of nylon 6/MPCM nanofibres decreased from 0.23 § 0.03 mm for neat nylon 6 to a minimum of 0.10 § 0.02 mm for composite yarn containing 3 wt% MPCM. However, nylon 6/MPCM nanofibre yarn diameter displayed a complex behaviour; the average diameters of electrospun composite yarns increased upon addition of MPCM and reached a maximum value of 165.1 § 5.11 mm for composite yarn containing 0.75 wt% MPCM, then decreased markedly. These changes in nylon 6/MPCM nanofibres and yarn diameters have been discussed in terms of electrospinning solution properties and twist parameter. The melting enthalpy values of MPCM in the composite nanofibre yarns increased as the content of MPCMs increased up to the highest content and higher than 80% of the heat storage capacity of MPCMs was retained after electrospinning.

Poly(l-lactide) nano/micro fibres were produced using the electrospinning technique. The influence of solvent type and solution concentration on the morphology and structure of electrospun fibres were investigated. For this purpose, the electrospinning was performed using 2, 2, 2-trifluoroethanol (TFE) or dichloromethane (DCM) solvents at solution concentrations in a range of 5-9 wt-%. Morphological studies showed that versus DCMbased fibres with beaded structures and porous surface, when using TFE as a solvent, the uniform bead-free fibres with a smooth surface morphology were produced. Compared to DCM, the fibre diameter decreased using TFE as a solvent with lower vapour pressure while the crystallinity of the fibres increased. By increasing the solution concentration up to 9 wt-%, uniform fibres were produced with growing average diameters. Following these results, we conclude that varying the solution concentration and solvent type can modulate the final properties of electrospun fibres.

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