Self-templated methods

The noncovalent self-assembly method relies on less specific types of interactions, including electrostatic, hydrogen bonding, metal ion coordination, Van der Waals forces, and/or hydrophobic attractions.8 In this approach, the template and the polymerizable monomer (i.e., an organoalkoxysilane) are judiciously chosen so that they will have complementary interactions. Removal of the template is easier than in the covalent assembly approach and often involves simply washing the materials in a suitable solvent.8... 

Relatively few studies on the synthesis of mesoporous alumina have been reported to date [8]. One of the limitations of the reported synthetic strategies is that the rate of hydrolysis (and condensation) reaction of aluminum alkoxide are much faster than that of silicon alkoxide. In this study, we proposed a novel method to prepare bimodal porous aluminas with meso- and macropores with narrow pore size distribution and well-defined pore channels. The fiamewoik of the porous alumina is prepared via a chemical templating method using alkyl caiboxylates. Here, self-assemblied micelles of carboxylic acid were used as a chemical template. Mesoporous aluminas were prepared through carefiil control of the reactants pH, while the procedures are reported elsewhere [9]. 

Fig. 12.7 Schematic diagram describing hollow capsule production by exploiting colloidal templating and self-assembly methods [12.8). Explanation see text.

Several reviews covering the synthesis, properties and applications of porous carbons, especially mesoporous carbon materials, can be found in the literature. In this chapter, we summarise the recent developments in the synthesis and characterisation of templated porous carbon materials. Particular attention is paid to the synthesis of structurally ordered porous carbon materials with narrow pore size distribution via both hard and soft template methods. We especially emphasise those so-called breakthroughs in the preparation of porous carbon materials. The chapter is divided into three sections according to the pore size of carbon materials we first consider the synthesis of microporous carbon materials using zeolites and clays as hard template, then summarise the preparation of mesoporous carbon materials via both hard template and self-assembly... 

The pore size of mesoporous carbon is of importance with respect to practical applications. When mesoporous carbon is synthesised via soft-template methods, the self-assembly of organic-organic species and pore size can be influenced by synthesis conditions, including surfactant type and concentration, and synthesis temperature. For example, Meng et al. observed that the pore size of mesoporous carbon derived from soft-templated mesoporous polymer composites decreased from 7.4 to 5.9 nm when the pyrolysis temperature increased from 400 to 800 How-... 

Miscellaneous Soft-Template Methods Novel Y-junction PANI-NTs, accompanied with nanorods, have been selectively prepared using in situ self-assembly of water-soluble Fe304 nanoparticles coated with PEG(5)-nonylphenylether and cyclodextrin as templates and pH control in an aqueous medium [373]. A chemical oxidative route to synthesize oriented arrays of conducting PANI-NTs in HCl solution by hydrogen-bonding directionality in the presence of a crown ether derivative (CE-SO3K) has also been reported [374]. 

However, each currently developed method has its own disadvantages. Hard-template methods, for instance, are a universal and controlled approach to obtaining conducting-polymer nanostructures, but the requirement of a template and the post-treatment for template removal not only results in a complex preparation process, but can also destroy the formed structures. Moreover, the size and morphology of available templates is limited. The soft-template method is another relatively simple, cheap, and powerfid approach to obtain CPCs via a self-assembly process. However, the morphology and size control of the self-assembled nanostructures obtained is poor. Therefore, finding a facile, efficient, and controlled route to prepare CPs nanostructures is desirable. 

Tavakkoli, K.G., Nicaise, S.M., Hannon, AE., Gotrik, K.W., Alexander-Kate, A., Ross, C.A., et al., 2014. Self-assembly sacrificial-post templating method for block copolymer self-assembly. Small 10 (3), 418-418. 

Template-Free Self-Assembly Methods Template methods for the preparation of ID NP assemblies have several intrinsic disadvantages. For instance, linear templates may have a considerable effect on both the photonic and electronic properties of the resulting ID NP assemblies. Although post-synthetic physical or chemical treatment can help remove the templates, it is possible that they also cause morphological and structural alterations to the NP chains, which are detrimental to their application. There has been a growing realization in the research... 

---