One-Pot Synthesis of Sequence-Controlled Mesoporous Heterostructures

Abstract Multi-material heterostructures have led to novel characteristics beyond the individual components. Nature controls the architecture and placement of multiple materials through biomineralization of nanoparticles (NP), however, synthetic heterostructure formation remains limited and departs from the elegance of self-assembly. Structure directing agents (SDA) enable nanocomposite self-assembly, however, these are limited to random mixtures due to dynamic (non-covalent) SDA-NP interactions.Here persistent (covalent) SDA-NP interactions enable sequence-controlled heterostructures where the composition profile and interfaces correspond to the synthetic addition order. This approach is generalized with 5 material sequences using a diblock polymer with persistent SDA-NP interactions (P-NP1-NP2; NPi=TiO2, Nb2O5, ZrO2). The addition of a dynamically interacting block with a bis- hydrophilic triblock terpolymer (PD-NP1-NP2) improves long-range ordering. The resulting competitive binding (P- vs D-blocks) required time for the first NP-type (NP1) to permeate the outermost D-block prior to covalent linkage with the central P-block. Thus, the bis-interacting triblock enabled mesoporous heterostructure synthesis via self-assembly for the first time.