Growth of Extra-Large Chromophore Supramolecular Polymers for Enhanced Hydrogen Production

Abstract

The control of morphology in bioinspired chromophore assemblies is key to the rational design of functional materials for light harvesting. We investigate here morphological changes in perylene monoimide chromophore assemblies during thermal annealing in aqueous environments of high ionic strength to screen electrostatic repulsion. We found that annealing under these conditions leads to the growth of extra-large ribbon-shaped crystalline supramolecular polymers of widths from about 100 nm to several micrometers and lengths from 1 to 10 μm while still maintaining a unimolecular thickness. This growth process was monitored by variable-temperature absorbance spectroscopy, synchrotron X-ray scattering, and confocal microscopy. The extra-large single-crystal-like supramolecular polymers are highly porogenic, thus creating loosely packed hydrogel scaffolds that showed greatly enhanced photocatalytic hydrogen production with turnover numbers as high as 13 500 over ∼110 h compared to 7500 when smaller polymers are used. Our results indicate great functional opportunities in thermally and pathway-controlled supramolecular polymerization.

Hybrid Nanocrystals of Small Molecules and Chemically Disordered Polymers

“…Under these conditions, the supramolecular monomer CA 1 assembled into interdigitated bilayers (Figure 1a) that form micron-sized nanoribbons (Figure 1c,d) as reported previously. 40 Surprisingly, we observed that the chemically disordered covalent polymer 2 formed predominantly highaspect-ratio nanostructures with widths 2 orders of magnitude narrower than the nanoribbons formed by CA 1, consistent with a change in slope from −1 to −2 in the small-angle region of the X-ray scattering patterns (Figure 1e,f). Under the conditions investigated, this morphology did not change with the degree of chromophore functionalization of the covalent polymer (Supporting Information Figures S7−S16).…”

A Self‐Assembling Flavin for Visible Photooxidation

“…For example, the self‐assembly of a single amino acid‐functionalized perylene bisimide results in different structures depending on the pH of the system and the efficiency of this perylene bisimide as part of a photocatalytic system depends on the structures formed [8] . Similar observations have been made for other systems [9] …”

“…[8] Similar observations have been made for other systems. [9] To the best of our knowledge, only two single flavin-based low molecular weight gelators have been reported. [10] One was used for the aerobic reduction of olefins.…”

Directional Supramolecular Polymerization in a Dynamic Microsolution: A Linearly Moving Polymer’s End Striking Monomers

“…For this study, we selected perylene bisimide (PBI) derivatives as the monomers because their self-assembly is well documented (Figure a). We designed PBIs having peripheral C12 alkyl moieties connected to the PBI scaffold through spacers of different lengths (C n , with n equal to 3 and 4 in PBI-C3 and PBI-C4, respectively). We have previously described how the nucleation processes of these PBI derivatives can be accelerated under microflow conditions .…”