Control of Ordering and Structure in Soft Templated Mesoporous Carbon Films by Use of Selective Solvent Additives

Abstract

The structure of ordered mesoporous carbons fabricated using poly(styrene-block-N,N,-dimethyl-n-octadecylamine p-styrenesulfonate) (PS-b-PSS-DMODA) as the template and phenolic resin (resol) as the carbon source can be easily manipulated by inclusion of low concentrations of low volatility selective solvents in the casting solution. Casting from neat methyl ethyl ketone yields a disordered structure even upon thermal annealing. However, addition of both dioctyl phthalate (DOP, PS selective) and dimethyl sulfoxide (DMSO, resol and PSS-DMODA selective) at modest concentrations to this casting solution provides sufficient mobility to produce highly ordered films with cylindrical mesopores. The DOP acts to swell the hydrophobic domain and can more than double the mesopore size, while the DMSO acts to swell the resol phase. Moreover, the surface area of the mesoporous carbons increases significantly as the meosopore size increases. This is a result of the decrease in wall thickness, which can be ascertained by the constant d-spacing of the mesostructure as the pore size increases. This behavior is counter to the typical effect of pore swelling agents that increase the pore size and decrease the surface area. Moreover, with only 4 wt % DOP/DMSO in the solution (20 wt % relative to solids), the scattering profiles exhibit many orders of diffraction, even upon carbonization, which is not typically observed for soft templated films. Variation in the concentration of DOP and DMSO during casting enables facile tuning of the structure of mesoporous carbon films.

Controlling the Pore Size of Mesoporous Carbon Thin Films through Thermal and Solvent Annealing

“…Among these properties, the tunable pore size is one of the most important criteria that determine the performance of mesoporous carbon . Previously, the pore size of mesoporous carbon thin films was controlled by tuning the pore wall thickness of nanostructured silica in a “hard template” method, or adjusting the molecular weight of block copolymers in a “soft template” method . However, the “hard and soft template” methods require sophisticated synthesis of mesoporous silica and series of block copolymers, respectively, and both of them are costly and time‐consuming.…”

Cooperatively assembled, nitrogen-doped, ordered mesoporous carbon/iron oxide nanocomposites for low-cost, long cycle life sodium-ion batteries

“…The influence of the dicyandiamide (Ndoping agent) on the assembly must be considered in order to explain this decreased pore size and d-spacing. The addition of the dicyandiamide may act to partially compatibilize the hydrophilic and hydrophobic segments of the Pluronic template, which will have a similar effect as a plasticizer on the assembly of a block copolymer to decrease chain stretching and thus tend to decrease the d-spacing and the pore size [47].…”

Colloidal bimetallic platinum–ruthenium nanoparticles in ordered mesoporous carbon films as highly active electrocatalysts for the hydrogen evolution reaction

“…7,8 Ordered mesoporous carbon (OMC) coatings are well known for their high surface area and good electrical conductivity. [9][10][11] Size and spacing of their mesopores are well-defined and controllable, making them ideal supports for catalyst nanoparticles. 12,13 Metallic nanoparticles feature a high surface area to volume ratio.…”