Synthesis of ultrafine carbon cryogel microspheres using a homogenizer

Abstract

in Wiley InterScience (www.interscience.wiley.com).Ultrafine carbon cryogel (UCC) microspheres of diameter <5 mm with desirable mesopores were successfully synthesized using a homogenizer during the inverse emulsion polymerization of a resorcinol-formaldehyde (RF) aqueous solution in an organic solvent as a continuous phase (CP) containing nonionic surfactant, SPAN80 as an emulsifier, followed by solvent exchange, freeze-drying, and pyrolysis in an Ar atmosphere. The curing time of RF solution before emulsification is a significant factor in controlling the size of the microspheres without changing their porosity. Both the mesoporosity and the size of the microspheres decreased on increasing SPAN80 and RF solution concentration in an inverse emulsion, which showed the possibility of controlling the mesoporosity and the size of the UCC microspheres. Furthermore, hexane could also be used as the continuous phase in the emulsion polymerization. The mean diameter of the UCC microspheres increased and their mesopore volume decreased with increasing pyrolysis temperature.

Preparation and characterization of nickel-modified carbon cryogel beads with uniform particle size

“…This can be explained by the significant difference in the viscosity of the RF solution, shown in Fig. 2, which was also mentioned in previous reports [25,40]. In this study, the CV values of the Ni/CCB were below 10%, irrespective of the Ni content.…”

“…Yamamoto et al [2] reported the synthesis of spherical carbon cryogels by the inverse emulsion polymerization of resorcinol-formaldehyde (RF) solution. Soottitantawat et al [25] succeeded in preparing ultrafine carbon cryogel microspheres by using a homogenizer during the inverse emulsion polymerization. The curing time of RF solution before emulsification significantly influenced the size of the microspheres without changing their porosity.…”

Synthesis of carbon xerogel nanoparticles by inverse emulsion polymerization of resorcinol–formaldehyde and their use as anode materials for lithium-ion battery

“…[1][2][3][4][5][6][7][8][9][10][11] As carbon cryogel and aerogel microspheres possess large surface area, they have been well studied for their use as electrochemical double layer capacitors due to their enhanced double layer capacitance. [1][2][3][4][5][6][7][8][9][10][11] As carbon cryogel and aerogel microspheres possess large surface area, they have been well studied for their use as electrochemical double layer capacitors due to their enhanced double layer capacitance.…”

Cryogels: Morphological, structural and adsorption characterisation

“…There are, at least, four different types of materials named "cryogels": (i) gelatinous precipitate forming during cryoprecipitationblood plasma treatment upon cooling to ca. 4°C [57]; (ii) frozen polymeric or other hydrogels used 14 as antipyretic materials or materials for thermal energy storage [58]; (iii) polymeric and inorganic cryogels produced using sol-gel technology with subsequent freeze-drying including individual and mixed inorganic oxides, polymers, hybrids, composites, and carbon cryogels (the latter is prepared by carbonisation of polymeric cryogels) [59][60][61][62][63][64][65][66][67] There are many cryogels prepared from synthetic polymers such as poly(vinyl alcohol), PVA, which was one of the first polymers used in cryogel preparation [2][3][4]36,38,74,78,82]. PVA alone or in combination with other polymers or proteins is very popular material for the cryogel preparation because its structure containing the (-CH 2 -C(OH)H-) n chain allows various degrees of cross-linking with the participation of the active COH groups, different cross-linkers and co-polymers.…”