Templated synthesis, polymeric nanofibers

There are several techniques that allow to produce polymeric nanofibers, such as drawing, template synthesis, phase separation, self-assembly, solution blow spinning, and electrospinning. The drawing process requires a polymer with appropriate viscoelastic properties that is able to be deformed and kept connected by cohesive forces. Besides being simple and inexpensive, this technique is very limited for conjugate polymers, since most of them have lower solubility and form solutions with a small viscous modulus. 

There are various methods to synthesize polymer nanostructures, i.e., template synthesis, chiral reactions, self-assembly, interfacial polymerization and electrospinning. Recent developments in conducting polymer nanotubes and nanofibers were summarized by Long et al. Different preparation methods, physical properties, and potential applications of one-dimensional nanostructures of conjugated polyaniline (PANI), pol5 3nrole (PPy) and poly (3, 4-ethylenediox3d hiophene) (PEDOT) were discussed. 

Polymer nanofibers can be synthesized by several general methods. The most common techniques are template synthesis [13], chiral reaction [14], self-assembly [15], interfacial polymerization [16,17], and electrospinning technique [18]. 

A bulk synthesis of PPy nanofiber (diameter 60-90 nm) was performed using nanofiber seeds as a template [232]. V2O5 nanofiber (diameter 15 nm), which was chemically treated with pyrrole monomer, was used as a reactive seed template, and pre-polymerization reaction on the surface of fibrillar template provided the evolution of bulk fibrillar morphology with subsequent addition of the oxidizing agent. 

There are a number of processing techniques to fabricate nanofibers, which include electrospinning, drawing, template synthesis, phase separation, interfacial polymerization, self-assembly, and so on [39,40]. Among these, electrospinning process is a very effective method to make porous hydrophobic membranes. 

Other studies in 2000 by Drew et al. reported that it is very difficult to spin fibers of PANI complexed to sulfonated polystyrene (PANFSPS), even when solutions containing sodium chloride and dodecyl benzene sulfonic acid sodium salt were used to lower the surface tension and thereby enhance electrospinning [16,17]. However, PANFSPS nanofibers can be produced by adding a carrier polymer such as PEO, polyacrylonitrile, or polyurethane. Also reported was the use of electrostatically layered sulfonated polystyrene as a template for the surface polymerization of conjugated polymers in their conducting form. Enzymatic synthesis of PANI and a copolymer of pyrrole and PEDOT was done on electrospun nanofiber... 

Template-free techniques have been extensively studied for the fabrication of conducting polymer nanomaterials fabrication. Compared with hard and soft template methods, these methodologies provide a facile and practical route to produce pure, uniform, and high quality nanofibers. Template-free methods encompass various methods such as electrochemical synthesis, chemical polymerization, aqueous/organic interfacial polymerization, radi-olytic synthesis, and dispersion polymerization. 

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