Self-assembled organic nanomaterials can be generated by bottom-up assembly pathways where the structure is controlled by the organic sequence and altered using pH, temperature, and solvation. In contrast, self-assembled structures based on inorganic nanoparticles typically rely on physical packing and drying effects to achieve uniform superlattices. By combining these two chemistries to access inorganic-organic nanostructures, we aim to understand the key factors that govern the assembly pathway and structural outcomes in hybrid systems. In this work, we outline two assembly regimes between quantum dots (QDs) and reversibly binding peptoids. These regimes can be accessed by changing the solubility and size of the hybrid (peptoid-QD) monomer unit. The hybrid monomers are prepared via ligand exchange, assembled, and resulting assemblies are studied using ex-situ transmission electron microscopy as a function of assembly time. In aqueous conditions, QDs were found to stabilize certain morphologies of peptoid intermediates and generate a unique final product consisting of multilayers of small peptoid sheets linked by QDs. The QDs were also seen to facilitate or inhibit assembly in organic solvents based on the relative hydrophobicity of the surface ligands, which ultimately dictated the solubility of the hybrid monomer unit. Increasing the size of the QDs led to large hybrid sheets with regions of highly ordered square-packed QDs. A second, smaller QD species can also be integrated to create binary hybrid lattices. These results create a set of design principles for controlling the structure and structural evolution of hybrid peptoid-QD assemblies and contribute to the predictive synthesis of complex hybrid matter. TOC Graphic.
Introduction.Hierarchically organized nanomaterials are often generated by mimicking natural systems wherein functional properties emerge due to order and organization across multiple length scales 1-3 . To predictively generate such materials, we must understand and systematize the atomic-level interactions that lead to organization of the functional building blocks across length scales. Traditionally, hybrid organic-inorganic nanomaterials are synthesized via bottom-up assembly or through templated assembly on a scaffold [4][5][6][7] . In these approaches, organic molecules, which are typically DNA, peptides (or peptoids), polymers, or small multitopic organic molecules, are used as the structure-directing elements with covalent and non-covalent interactions dictating the possible assembly outcomes 1,5-13 . These interactions are dependent on the sequence used and can often be controlled using pH, temperature, electrolytes, solvent, and/or pendant groups [14][15][16][17][18] . When inorganic nanoparticles act as the driving force for assembly, the generated structures are often a result of particle packing and drying effects. In these systems, the structures can be tuned through size, surface chemistry, ligand packing or morphology of the nanoparticles but frequently lack precision and are ...