Polyaniline soft templates

W. Zhong, J. Deng, Y. Yang, and W. Yang, Synthesis of large-area three-dimensional polyaniline nanowire networks using a soft template , Macromol. Rapid Commun., 26, 395-400 (2005). 

Using functional molecules as structural directors in the chemical polymerization bath can also produce polyaniline nanostructures. Such structural directors include surfactants [16-18], liquid crystals [19], polyelectrolytes (including DNA) [20,21], or complex bulky dopants [22-24]. It is believed that functional molecules can promote the formation of nanostructured soft condensed phase materials (e.g., micelles and emulsions) that can serve as soft templates for aniline polymerization (Figure 7.3). Polyelectrolytes such as polyacrylic acid, polystyrenesulfonic acid, and DNA can bind aniline monomer molecules, which can be polymerized in situ forming polyaniline nanowires along the polyelectrolyte molecules. Compared to templated syntheses, self-assembly routes are more scalable but they rely on the structural director molecules. It is also difficult to make nanostructures with small diameters (e.g., <50 nm). For example, in the dopant induced self-assembly route, very complex dopants with bulky side groups are needed to obtain nanotubes with diameters smaller than 100 nm, such as sulfonated naphthalene derivatives [23-25], fidlerenes [26], or dendrimers [27,28]. 

The conventional chemical polymerization of polyaniline only produces nonfibrous or irregular shaped morphologies [237,238], In the past several years, a variety of chemical methods were reported that yield polyaniline nanofibers, such as use of hard templates [239,240], soft templates [241], electrospinning [242], interfacial polymerization [237], and seeding polymerization [238]. Recently, Chiou and Epstein discovered that polyaniline nanofibers can be directly synthesized in dilute chemical polymerization... 

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