Relationship between crosslinking and ordering kinetics for the fabrication of soft templated (FDU-16) mesoporous carbon thin films

Abstract

Although the fabrication of mesoporous carbon films through the cooperative assembly of phenolic resin oligomers (resol) and block copolymers is well-established, these methods generally rely upon simply following protocols developed for analogous bulk powders despite growing evidence of significant differences between thin films and bulk powders. Here, we examine the chemical evolution of resol through spectroscopically tracking the methylol content for films with and without a common templating agent (Pluronic F127). At lower temperature (100 °C and 120 °C), the crosslinking rate is not impacted by the presence of the template, while the addition of the Pluronic template decreases the reaction rate at higher temperatures (140 °C and 160 °C). At all conditions examined, the crosslinking kinetics of resol can be fit using the Jander model. in situ grazing incidence small angle X-ray scattering illustrates that the mesostructural evolution is not highly correlated with the chemical changes during crosslinking. With this knowledge, a shortened processing schedule (3 h total) was devised in place of the standard 24 h thermopolymerization without adversely impacting the ordered structure of the mesoporous film and this protocol significantly increases (almost double) the porosity of the film.