Core/shell fiber structures

S Natarajan, S Michielsen. The use of confocal Raman microscopy for determining the structure and orientation of the PET interior of PET/PP core/shell fibers. Textile Res J 69 903-907, 1999. C Galiotis, IM Robinson, R.T Young, BJE Smith, DN Batchelder. Strain dependence of the Raman frequencies of a Kevlar 49 fibre. Polym Commun 26 354-355, 1985. 

Generally, it is important to know how to fabricate fibers with circular cross sections at will, and the aim of electrospinning for particular applications is in general to obtain just these particular types of fibers. On the other hand, other types of structure of fibers may be beneficial for specific functionality and applications. To date, by carefully controlling the preparing conditions, a variety of specific fiber structures originating from the complex self-assembly processes intrinsic in electrospinning have been fabricated, such as ribbon fiber, helix fiber, porous fiber, necklace-like fiber, core-shell fiber, and hollow fiber, as shown in Fig. 1.13. 

Chen HY, Wang N, Di JC, Zhao Y, Song YL, Jiang L (2010) anowire-in-microtube structured Core/Shell fibers via multifluidic coaxial electrospinning. Langmuir 26 11291-11296... 

PF nanofibers are a second example of a top-down nanostructure. These fibers are conveniently prepared by electrospinning [143,144], a technique applied to PFs in work by Chen et al. [145] and Jenekhe et al. [146]. An example of PF8 nanofibers is shown in Fig. 34. In this study various different PFs were blended with PMMA and depending on the molar ratio and mother solution used, either uniform or core-shell structures were obtained. PF ag-... 

By contrast, the immiscible lignin/PP blend fibers form unique core/shell structure due to the difference... 

Jiang HL et al (2006) Modulation of protein release from biodegradable core-shell structured fibers prepared by coaxial electrospinning. J Biomed Mater Res B Appl Biomater 79B(1) 50-57... 

A coaxial setup uses a multiple solution feed system that allows for the injection of one solution into another at the tip ofthe spinneret. The sheath fluid act as a carrier drawing in the inner fluid at the Taylor cone ofthe electrospinning jet. If the solutions are immiscible then a core-shell structure is usually observed. Miscible solutions, however, can result in porosity or a fiber with distinct phases due to phase separation during solidification ofthe fiber. 

The adhesion of aramid fiber composites can be improved by a core/shell structure of meta-aramid/epoxy nanofibers [29]. The polymer blends are prepared by electrospinning to enhance the interface adhesion. 

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