Polymer Templating Routes

Mullner M, Lunkenbein T, Miyajima N, Breu J, Muller AHE (2012) A facile polymer templating route toward high-aspect-ratio crystalline titania nanostructures. Small 8(17) 2636-2640... 

Sinha NN, Munichandriaah N (2010) High rate capability of porous LiNii/3Mni Coi 02 synthesized by polymer template route. J Electrochem Soc 157 A647-A653... 

Zeolites have been incorporated into and attached to fibers of various compositions for a number of applications. The types of fibers that have been used include glass [105], polymers by addition to the monomer prior to polymerization [106], optical fibers [107], cellulose pulp [108] and self-supported hoUow zeoHte fibers by a templating route [109]. 

Chitosan-coated CdSe quantum dots (CdSe/CS QDs) were synthesized through a polymer-template-assisted y-radiation route in aqueous system at room temperature under ambient pressure (Kang et al. 2008). No surfactants were used in any reaction process. The synthesized QDs were cubic zinc blende. The QDs exhibited an absorption peak at 460 nm and an emission peak at 535 nm. Under UV illumination, the QDs exhibit light green fluorescence in aqueous solution (Figure 23.4). These QDs might be useful for biological application. This method can be considered as an improvement to the conventional radiation route. 

K. Jackowska, A. T. Biegunski, and M. Tagowska, Hard template synthesis of conducting polymers a route to achieve nanostructures, J. Solid State Electrochem., 12, 437-443 (2008). 

A soft template route involves an organic compound, such as polymers or surfactants, which is used as a direct mold in order to obtain a structured carbon precursor. Then, the soft template is eliminated during the carbonization stage. Nowadays, there are a large number of preparation methods reporting materials with a wide variety of structures and pore size distributions. In general, these methods are more versatile and cheaper than nanocasting ones. Moreover, the... 

New route to three-dimensional photonic bandgap materials silicon double inversion of polymer templates. Adv. Mat., 18 (4), 457-460. 

A mathematical model for template polymerization similar to the biological process was elaborated by Simha and co-workers. The purpose of their paper was to explore mathematical consequences of alternative kinetic routes to the formation of polymer chains on polymer templates. However, since then, nobody has tried to use this theory for the description of template processes. 

Sol-gel processing forms the basis for various routes employed for the fabrication of a wide diversity of functional materials. To impart a structural organization at various length scales, the syntheses are performed using templates. Most consist of a self-organized ensemble of surfactants and co-polymers [1-10]. They have been successfully applied to control the geometry and dimensions of pores that are periodically arranged as in the initial structures. Mesoporous silica materials of the MCM family, which were first synthesized by a team from the Mobil oil company [11,12], are a well-known example. 

Transition-metal nanopartides are of fundamental interest and technological importance because of their applications to catalysis [22,104-107]. Synthetic routes to metal nanopartides include evaporation and condensation, and chemical or electrochemical reduction of metal salts in the presence of stabilizers [104,105,108-110]. The purpose of the stabilizers, which include polymers, ligands, and surfactants, is to control particle size and prevent agglomeration. However, stabilizers also passivate cluster surfaces. For some applications, such as catalysis, it is desirable to prepare small, stable, but not-fully-passivated, particles so that substrates can access the encapsulated clusters. Another promising method for preparing clusters and colloids involves the use of templates, such as reverse micelles [111,112] and porous membranes [106,113,114]. However, even this approach results in at least partial passivation and mass transfer limitations unless the template is removed. Unfortunately, removal of the template may re-... 

Various metal and metal oxide nanoparticles have been prepared on polymer (sacrificial) templates, with the polymers subsequently removed. Synthesis of nanoparticles inside mesoporus materials such as MCM-41 is an illustrative template synthesis route. In this method, ions adsorbed into the pores can subsequently be oxidized or reduced to nanoparticulate materials (oxides or metals). Such composite materials are particularly attractive as supported catalysts. A classical example of the technique is deposition of 10 nm particles of NiO inside the pore structure of MCM-41 by impregnating the mesoporus material with an aqueous solution of nickel citrate followed by calicination of the composite at 450°C in air [68]. Successful synthesis of nanosized perovskites (ABO3) and spinels (AB2O4), such as LaMnOs and CuMn204, of high surface area have been demonstrated using a porous silica template [69]. 

Based on the original Stoeber synthesis which leads to nonporous silica particles we developed a novel route to synthesize mesoporous silica particles. All syntheses were carried out in an homogeneous solution of alcohol/water/ammonia. To control the porosity of the obtained particles, polymers were used as templates. 

It should be mentioned that the defined interaction of dextran sulfate with amino functions is not only applied for the design of structures on the su-permolecular level but also on the molecular level. Thus, a preferred handed helical structure was induced into the polyaniline main chains by chemical polymerisation of achiral aniline in the presence of dextran sulfate as a molecular template. This affords a novel chemical route for the synthesis of chiral conducting polymers [158]. 

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