Wet and Functional Adhesives from One‐Step Aqueous Self‐Assembly of Natural Amino Acids and Polyoxometalates

Abstract

Sessile organisms have undergone long-term evolution to develop the unique ability by positioning themselves on wet solid surface through secreting adhesive proteins. The present study reveals that natural amino acid monomers can also exhibit similar adhesion capacity. This kind of biomimetic adhesives were created by the one-step aqueous assembly of basic amino acids with assistance of anionic polyoxometalates. The polyoxometalates not only serve as multivalent scaffold to initiate the supramolecular cross-linking of amino acid molecules, but also function as a redox component, bestowing the wet adhesives with electrochromic features.

Beyond Charge Balance: Counter‐Cations in Polyoxometalate Chemistry

“… a) Nanofiber formation by electrostatic aggregation between [SiW 12 O 40 ] 4− and cationic oligopeptides capable of π stacking . b) Adhesive formation by electrostatic and hydrogen‐bonding aggregation between [SiW 12 O 40 ] 4− and hydrogen‐bonded cationic histidine dimers …”

Jenseits von Ladungsausgleich: Gegenkationen in der Polyoxometallat‐Chemie

“… a) Bildung von Nanofasern durch elektrostatische Aggregation von [SiW 12 O 40 ] 4− und kationischen Oligopeptiden mit π‐Stapelaktivität . b) Klebstoffbildung durch elektrostatische Wechselwirkungen und Wasserstoffbrücken zwischen [SiW 12 O 40 ] 4− und wasserstoffverbrückten kationischen Histidindimeren …”

“…Auf Basis ähnlicher Aufbauprinzipien zwischen POMs und Biomolekülen haben Li und Mitarbeiter die Nassklebstoffe verschiedener Mollusken (z. B. Muscheln) nachgeahmt, indem sie das Keggin‐POM [SiW 12 O 40 ] 4− mit der kationischen Aminosäure Histidin als Gegenion kombinierten. Die Aggregation der Komponenten fand in wässriger Lösung bei einem pH‐Wert von 3 statt, bei dem die Imidazolseitengruppe des Histidins protoniert ist und die α‐Aminosäure in ihrem zwitterionischen Zustand vorliegt, sodass eine einfach positive Ladung und entsprechend ein POM/Histidin‐Verhältnis von 1:4 resultieren.…”

Coassembly of a Polyoxometalate and a Zwitterionic Amphiphile into a Luminescent Hydrogel with Excellent Stimuli Responsiveness

“…[5c, 14] However,f or the EuW 10 /C 12 IPS aqueouss ystem, no significant enthalpy change was observed ( Figure 1b)a nd ac larified aqueous solution was obtained. Compared with cation amphiphiles, zwitterionic amphiphiles possess tethered ac ation and anion.T herefore, the electrostatic repulsion betweens ulfonica nionsa nd [EuW 10 O 36 ] 9À anions will significantly weaken the electrostatic attraction between imidazolium cations and [EuW 10 O 36 ] 9À anions. The moderate electrostatic interactions enable the coassembly of zwitterionic amphiphiles and POMc lusters to be achieved in aqueous system.…”

“…Wu et al constructed functional adhesives in an aqueous system by coassembly of POM and naturala mino acids. [10] Thez witterionic groups (NH 3 + and COO À )o btainedb ya djusting pH were more conducive to prepareh ighly concentrated superstructures and enhancet he interfacial binding affinity between adhesives and solid surfaces. Applying this attractive coassembly method to other POMs was expected to allow the construction of soft materials with more applications.…”