Access to Metastable Gel States Using Seeded Self‐Assembly of Low‐Molecular‐Weight Gelators

• Published in: Angewandte Chemie International Edition Vol. 58; no. 12; pp. 3800 - 3803
• Main Authors: Wang, Yiming, de Kruijff, Robin M., Lovrak, Matija, Guo, Xuhong, Eelkema, Rienk, van Esch, Jan H.
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 18.03.2019
• Edition: International ed. in English
• Subjects: Assembly; Gels; Hydrazones; Low molecular weights; low-molecular-weight gelators; Metastatic seeding; Morphology; Oligomers; out-of-equilibrium systems; seeded self-assembly; Seeds; Stiffness; supramolecular chemistry; Supramolecular compounds; Thermodynamic equilibrium; seeded self-assembly; gels; out-of-equilibrium systems; supramolecular chemistry; low-molecular-weight gelators
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201812412

Here we report on how metastable supramolecular gels can be formed through seeded self‐assembly of multicomponent gelators. Hydrazone‐based gelators decorated with non‐ionic and anionic groups are formed in situ from hydrazide and aldehyde building blocks, and lead through multiple self‐sorting processes to the formation of heterogeneous gels approaching thermodynamic equilibrium. Interestingly, the addition of seeds composing of oligomers of gelators bypasses the self‐sorting processes and accelerates the self‐assembly along a kinetically favored pathway, resulting in homogeneous gels of which the network morphologies and gel stiffness are markedly different from the thermodynamically more stable gel products. Importantly, over time, these metastable homogeneous gel networks are capable of converting into the thermodynamically more stable state. This seeding‐driven formation of out‐of‐equilibrium supramolecular structures is expected to serve as a simple approach towards functional materials with pathway‐dependent properties. Out‐of‐equilibrium supramolecular gels were generated by a simple seeding‐driven self‐assembly strategy. The addition of seeds forces the self‐assembly of synthetic gelators along a kinetically favoured pathway, leading to metastable gels which are capable of converting into the thermodynamically more stable gel states over time.