Porous electrospinning

Kwon and coworkers prepared a series of nano- to microstmctured biodegradable PCLA porous fabrics by electrospinning. The nanoscale-fiber porous fabrics were electrospun with PCLA (1 1 mole ratio, approximately 0.3-1.2 mm in diameter) using l,l,l,3,3,3-hexafluoro-2-propanol as a solvent. 

Yu Y, Gu L, Zhu C, Van Aken PA, Maier J. Tin nanoparticles encapsulated in porous multichannel carbon microtubes preparation by single-nozzle electrospinning and application as anode material for high-performance Li-based batteries. J Am Chem Soc. 2009 131 15984-5. 

In another application electrospinning [189] of PS-fo-P4VP(PDP)i.o supra-molecules was used to produce internally structured fibers with diameters in the range of 200-400 nm. Due to the block copolymer sample selected, self-assembly resulted in spherical P4VP(PDP) domains with the well-known internal lamellar structure. After the PDP was extracted from the fibers using methanol, porous fibers were obtained [190]. With this method, the thickness of the fibers can be tuned by adjusting the spinning conditions, and the size and nature of the pores can be controlled by the choice of block copolymer and amount of amphiphile. 

Fig. 1 Nanofibrous architectures created by electrospinning (a) random nanofibers, (b) porous nanofibers, (c) core-shell nanofibers, (d) aligned nanofibers (e) nano-yam, (f) hollow nanotubes...

Teo WE et al (2005) Porous tubular stmctures with controlled fibre orientation using a modified electrospinning method. Nanotechnology 16(6) 918—924... 

Polymer-supported Ag nanoparticles have been widely investigated and provide potential applications as catalysts, photonic and electronic sensors, wound dressings, body wall repairs, augmentation devices, tissue scaffolds, and antimicrobial filters [15-22]. For these applications, Ag nanoparticles have to be supported in a biocompatible polymer system [23-26]. The electrospinning technique has often been adopted for the incorporation of Ag nanoparticles into polymer porous media. In this chapter, we review the preparation methods and properties of Ag nanoparticles incorporated into polymeric nanofibers and their applications in the fields of filtration, catalysis, tissue engineering and wound dressing. 

Highly porous chitosan-gelatin scaffolds by combining three different fabrication techniques, i.e., rapid prototyping, microreplication, and freeze-drying Natural nanofibrous scaffolds by electrospinning of GC into nanofibers... 

S. Nair, E. Hsiao, and S. H. Kim Fabrication of electrically-conducting nonwoven porous mats of polystyrene-polypyrrole core-shell nanofibers via electrospinning and vapor phase polymerization, J. Mater. Chem., 18, 5155-5161 (2008). 

FIGURE 5.4 Different types of porous chitosan scaffolds fabricated by (a) thermally induced phase separation [129], (b) dense CO gas foaming [132], (c) sintering chitosan microspheres, and (d) electrospinning [157]. Reprinted with permission. Copyright 1999, 2005, 2011 Elsevier. 

The CNY obtained by electrospinning technology is a porous nonwoven mat with a high absorption capacity. Due to its features this nanomaterial can be used for wound dressing, tissue scaffolds, drug delivery systems, etc. (Vargas, 2010). 

Other examples of nonplanar hierarchically structured porous films are for instance the preparation of membranes for advanced filtration (also known as microsieves) composed by a hierarchical pore structure [208] or the construction of hierarchical structures by combination of electrospinning or electrospraying and breath figures [209-211]. 

A shish-kebab model for tbe filament morphology was proposed. The electrospinning process was shown to be a means of creating porous thin films with structural gradients and controlled morphology that could enhance biocompatibility. 

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