Tailored Design of Bicontinuous Gyroid Mesoporous Carbon and Nitrogen‐Doped Carbon from Poly(ethylene oxide‐b‐caprolactone) Diblock Copolymers

Abstract

Highly ordered mesoporous resol-type phenolic resin and the corresponding mesoporous carbon materials were synthesized by using poly(ethylene oxide-b-caprolactone) (PEO-b-PCL) diblock copolymer as a soft template. The self-assembled mesoporous phenolic resin was found to form only in a specific resol concentration range of 40-70 wt % due to an intriguing balance of hydrogen-bonding interactions in the resol/PEO-b-PCL mixtures. Furthermore, morphological transitions of the mesostructures from disordered to gyroid to cylindrical and finally to disordered micelle structure were observed with increasing resol concentration. By calcination under nitrogen atmosphere at 800 °C, the bicontinuous mesostructured gyroid phenolic resin could be converted to mesoporous carbon with large pore size without collapse of the original mesostructure. Furthermore, post-treatment of the mesoporous gyroid phenolic resin with melamine gave rise to N-doped mesoporous carbon with unique electronic properties for realizing high CO adsorption capacity (6.72 mmol g at 0 °C).

Synthesis Strategies of Porous Carbon for Supercapacitor Applications

“…In a soft template synthesis strategy, the templates are usually organic molecules or supermolecules with functional groups 84,121. In the particular solvent, the functional groups of soft templates can provide strong interaction force, such as hydrogen bonding,137,138 hydrophilic and hydrophobic interactions,139,140 or electrostatic interactions 141,142. Once the proper solvent is added, the soft templates turn into micelles.…”

Mesoporous Carbons Templated by PEO‐PCL Block Copolymers as Electrode Materials for Supercapacitors

“…To fabricate the mesoporous carbons, we first synthesized an amphiphilic PEO-PCL block copolymer with specific molecular weightf ractions( EO 114 -CL 92 )a st he template;i np revious studies, we found that such templates are suitable for the preparation of ordered mesoporousc arbonsw ith hexagonal cylinder and gyroid structures. [26][27][28][29] The resol-type phenolic resin and this PEO-PCL template were dissolved in EtOH at as pecific weightr atio;t he microphase transferredg radually to an ordered structurea fter evaporation-induced self-assembly and curing in the oven, with the electrode materials for EDLCs upercapacitors obtained after carbonization and activation processes (Scheme 1). The weightr atios of resol to PEO-PCLc ould be regulated during the fabrication of the mesoporousc ar-bons to induce differentt ypes of microphase separation, based on the corresponding volume fractionso ft he PCL and resol/PEOd omains.…”

“…[31] The resol was prepared through condensation of phenol, CH 2 Ow ith NaOH, producing ar esol resin with an average molecular weight (M n )o fapproximately 500. [26]…”

“…[22,23] Many amphiphilic block copolymers have been used recently as templates for the synthesis of mesoporous carbons, including PEO-PS (poly(ethylene oxide)-block-polystyrene), [24] PEO-PMMA (poly-(methyl methacrylate)), [25] andP EO-PCL (poly(ethylene oxideblock-caprolactone)). [26] In previous studies, [26][27][28][29][30] we employed the macroinitiatoro fM PEO and the CL monomer to synthesize as eries of amphiphilic PEO-PCL block copolymers;t hese labmade templates could be tailoredw ith various molecular weights, thereby leading to variousm icrophase-separated structures. For this reason,P EO-PCL could be aw onderful candidate based on the flexibility of tunable pore size and pore structures of mesoporousc arbons.…”

Controlled synthesis of mesoporous nitrogen-doped carbons with highly ordered two-dimensional hexagonal mesostructures and their chemical activation

“…In contrast, the soft-templating method is a straightforward approach which is dependent on the self-assembly of the organic compounds and block copolymers into ordered mesostructured composites in a oriented manner through a chemical interaction. [9][10][11][12][13] Interestingly, the morphology, porosity, and structure could be tuned by controlling the synthetic conditions, such as the concentration of the surfactant, pH, and carbonization temperature. The morphological control will endow the product with an excellent chemical activity, mechanical stability, good electrical conductivity, and high surface area, which have been considered as the essential requirements for electrode materials used in energy storage applications.…”