Porous silica spheres in macroporous structures and on nanofibres

Abstract

Porous nanospheres have a wide range of applications such as in catalysis, separation and controlled delivery. Among these nanospheres, syntheses and applications of porous silica nanospheres have been investigated extensively. Uniform porous silica nanospheres can be synthesized using a modified Stöber method. In the present study, porous silica spheres were prepared in the pre-formed emulsion-templated porous polyacrylamide (PAM). A hierarchical hybrid structure of mesoporous silica spheres was formed in the highly interconnected macroporous polymer. The polymer scaffold could be removed by calcination with porous silica spheres and the macroporous structures retained. This resulted from the close packing or aggregation of small silica nanospheres in the pores and on the surface of pores of PAM. The modified Stöber synthesis was further carried out in pre-formed polymer nanofibres (chitosan and sodium carboxymethyl cellulose). The structure of porous silica spheres on nanofibres was produced in the presence of the polymer or composite fibres. The corresponding inorganic structures were successfully obtained after calcination. The hierarchical structures of porous nanospheres within macroporous structures or on nanofibres are of potential interest to researchers in nanomaterials, porous polymers, supported catalysis and controlled delivery.

Synthesis of Hierarchical Porous Silica by Sol‐Gel of Sodium Silicate and Nanoemulsion Templating: Effective Combination Conditions

“…Combining sol‐gel of sodium silicate with nanoemulsion templating is used to prepare hierarchical porous silica with comparative good surface area, pore size, and pore volume when compared to relative samples from literature as shown in Table 1 [27–30] . It shows very high pore volume which may be attributed to the.…”

“…The surface area is higher than samples prepared from sodium silicate and very close to the sample prepared from TEOS with 4 fold pore volume. It worth mentioning that sample from Ref., [29] Pluronic P84 is used to form micelles. The surface area increases with increasing Pluronic P84 concentration.…”

Resonance structure of quantum-dot-coated microspheres for microfluidic sensing

“…While a variety of chemical methods exist for synthesizing silica or polymer beads in solution 1,2,3,4,5 , the formation of a single high-quality microsphere for refractometric sensing uses predominantly physical methods. These methods involve heating and melting optical fiber such that a microscale "melt sphere" is formed on the end of the taper, by surface tension.…”

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“…In recent years, the studies of nanoparticles and nanostructures have attracted increasing interests worldwide. Porous nanospheres can potentially provide the advantages of both nanoparticles and high surface areas from micro-and mesopores in the nanoparticles (Ahmad et al 2010).…”