Switchable Self‐Assembly of a Bioinspired Alkyl Catechol at a Solid/Liquid Interface: Competitive Interfacial, Noncovalent, and Solvent Interactions

Abstract

The large tendency of catechol rings to adsorb on surfaces has been studied by STM experiments with molecular resolution combined with molecular-dynamics simulations. The strong adhesion is due to interactions with the surface and solvent effects. Moreover, the thermodynamic control over the differential adsorption of 1 and the nonanoic solvent molecules has been used to induce a new temperature-induced switchable interconversion. Two different phases that differ in their crystal packing and the presence of solvent molecules coexist upon an increase or decrease in the temperature. These results open new insight into the behavior of catechol molecules on surfaces and 2D molecular suprastructures.

Reversible Phase Transformation at the Solid–Liquid Interface: STM Reveals

“…Host-guest experiments showed that these two networks can selectively adsorb fullerene molecules, such as C 60 , C 70 , and C 80 , as guests. [77]. This transformation should contribute to the isomerization of the azobenzene unit in NN4A.…”

“…[72] Catechols and their derivatives are found in nature, taking part in a remarkably broad scope of biochemical processes and functions that range from the adhesive properties of marine organisms to the storage of some transition metal ions. [77] At room temperature (20 8C), the catechols form a molecular array with domains (i.e., the a phase) that extend from 10 nm up to a few hundred nanometers. [73][74][75][76] In a recent study, Saiz-Poseu and colleagues demonstrated that temperature control could be used to switch between two different lamellae of the alkylated catechols at the nonanoic acid/HOPG interface.…”

“…[73][74][75][76] In a recent study, Saiz-Poseu and colleagues demonstrated that temperature control could be used to switch between two different lamellae of the alkylated catechols at the nonanoic acid/HOPG interface. [77] At room temperature (20 8C), the catechols form a molecular array with domains (i.e., the a phase) that extend from 10 nm up to a few hundred nanometers. Furthermore, the submolecular STM image (Figure 2 b, left) revealed that the high-contrast aromatic cores form bright rows, while the long alkyl chains interdigitate with each other, as characterized by the shaded lines in this molecular packing.…”

Solvent‐Tuned Supramolecular Assembly of Fluorescent Catechol/Pyrene Amphiphilic Molecules

“…For instance, self‐assembled monolayers (SAM) with enhanced adhesion properties that mimic mussels have been reported for the use of 4‐(6′‐mercaptohexyl)catechol on different gold surfaces . Relevant information on the basic principles that govern the adhesion of catechols at the solid–liquid interface has also been obtained upon studying the self‐assembly of these molecules on different surfaces with STM . The precise development and immobilization of functionalized self‐assembled structures has also provided new (bio)active coatings with promising clinical or technological applications .…”

“…[8] Relevant information on the basic principles that govern the adhesion of catechols at the solid-liquid interface has also been obtainedu pon studying the self-assembly of thesem olecules on different surfaces with STM. [9] The precise development and immobilization of functionalized self-assembled structures has also provided new (bio)activec oatings with promising clinical or technological applications. [10] Moreover,s upramolecular selfassemblyd riven by catechol/metal ion coordination has afforded the fabrication of novel functional materials, including adhesives,capsules, coatings, andhydrogels, [11] and the formation of coordination polymer nanoparticles of technological relevance in different areas, such as molecular electronicso rn anomedicine.…”