Molecular insight into self-assembly mechanism of mesoporous polydopamine in emulsion system: morphology regulation and surface modification of graphene oxide

This study combines coarse-grained molecular dynamics and experimental methods to investigate the self-assembly mechanisms of mesoporous polydopamine (MPDA) and its graphene oxide (GO) derivatives. MPDA morphology was regulated by adjusting the PEO/PPO ratio in Pluronic copolymers and ethanol content in aqueous solutions. Simulations revealed that PPO-rich systems enhance Pluronic-trimethylbenzene (TMB) adsorption affinity, forming tighter MPDA-templating micelles, while PEO-rich systems are less conducive to stabilizing the micelles with weaker interfacial contact. However, achieving available MPDA structures cannot solely depend on the Pluronic-TMB affinity but requires balancing micelle-solvent hydrophilicity-lipophilicity, which is also precisely modulated by ethanol content. Research shows that an optimal TMB-solvent miscibility and interfacial tension can be determined with an ethanol fraction of 40–50 % required for PEO-rich systems but 20–40 % for PPO-rich systems. These findings further extend to the morphology-controlled MPDA@GO synthesis, demonstrating that higher PPO content correlates with larger mesopores but reduces their uniformity on GO, whereas lower ethanol fractions diminish morphological sensitivity to the PEO/PPO ratio variation. Additionally, the redox-induced consumption of dopamine (DA) by GO necessitated precise optimization of the DA/GO stoichiometric ratio and the oxidation degree GO to preserve mesoporous structure integrity. This work provides molecular-level insights into the interfacial interactions governing the synthesis of soft-templated mesoporous materials to guide the versatile hybridization of functional nanomaterials.