Programmable Surface Catalyzed Heterogeneous Nucleation Enables “Double-Cable” Light-Harvesting Supramolecular Polymers

Supramolecular polymerization has entered a vibrant new stage in which precise control over self-assembly pathways enables hierarchical topologies that emulate covalent polymer systems in structure and function, while also providing access to complex organic heterostructures previously inaccessible through bottom-up self-assembly strategies. In this context, the present work delivers the first precision-designed light-harvesting supramolecular donor-acceptor double-cable polymers with orthogonal heterojunctions, constructed through a surface-catalyzed heterogeneous nucleation pathway that mirrors well-defined covalent analogues. As a proof of concept, core substituted naphthalene diimide (cNDI) chromophores bearing tripeptide side chains and diverse optoelectronic characteristics are used as modular monomers, where the peptide units simultaneously (i) exploit their chirality to regulate the balance between elongation and surface catalyzed nucleation during seeding and (ii) provide a templated interface that stabilizes a secondary cable growing in parallel on top of a primary stack. Detailed kinetic analysis, guided by spectroscopic studies and concepts adapted from surface-catalyzed protein aggregation, reveals that chirality and seeding conditions selectively channel growth through heterogeneous surface nucleation while suppressing competing pathways. This level of control further enables programmable modulation of heterojunction length through sequential seeding. Furthermore, spectral and time-resolved fluorescence microscopy of individual supramolecular double-cable heterostructures demonstrate efficient resonance energy transfer between the parallel donor and acceptor cables, establishing light-harvesting functionality at the single-chain level. Overall, this study presents a unique manifestation of hierarchical supramolecular polymerization that pushes the limits of precision and complexity in supramolecular polymers, an advance that is crucial for the continued expansion of this exciting field.