Molecular Motions in Functional Self-Assembled Nanostructures

Abstract

The construction of “smart” materials able to perform specific functions at the molecular scale through the application of various stimuli is highly attractive but still challenging. The most recent applications indicate that the outstanding flexibility of self-assembled architectures can be employed as a powerful tool for the development of innovative molecular devices, functional surfaces and smart nanomaterials. Structural flexibility of these materials is known to be conferred by weak intermolecular forces involved in self-assembly strategies. However, some fundamental mechanisms responsible for conformational lability remain unexplored. Furthermore, the role played by stronger bonds, such as coordination, ionic and covalent bonding, is sometimes neglected while they can be employed readily to produce mechanically robust but also chemically reversible structures. In this review, recent applications of structural flexibility and molecular motions in self-assembled nanostructures are discussed. Special focus is given to advanced materials exhibiting significant performance changes after an external stimulus is applied, such as light exposure, pH variation, heat treatment or electromagnetic field. The crucial role played by strong intra- and weak intermolecular interactions on structural lability and responsiveness is highlighted.

Water structure and elastin-like peptide aggregation

“…More generally, the self-assembly molecules domain is of rising interest, involving the construction of smart materials able to perform specific functions at the molecular scale. If the self-assembly of organic nanostructures is mainly driven by weak intermolecular forces (van der Waals forces, hydrogen bonding and hydrophobic effect), strong intermolecular interaction such as ionic covalent and coordination bonds can also play a central role in the formation of self-assembled materials, enhancing the dynamic properties of the final supramolecule [30].…”

From monomers to self-assembled monolayers: the evolution of molecular mobility with structural confinements

“…[6][7][8][9][10][11] However, continuous shrinking of material structures and increasing number of interfaces may drastically reduce the ability of molecules to uctuate, or even vanish thermal glass transition phenomena due to molecule immobilization. 12,13 An exemplar representation of this tendency is reected by the incessant development of active and stimuli-responsive material systems, supramolecules, and self-assembled monolayers (SAMs).…”

Supramolecular self-assembly of linear oligosilsesquioxanes on mica – AFM surface imaging and hydrophilicity studies

“…PSAMs differ from typical SAMs because of conformational characteristics of macromolecular 45 chains that depend on the type and density of grafting as well as polymer-substrate affinity. Structure of SAMs and PSAMs strongly depends on chemical properties of the solid surface, its morphology, adsorption 60 mechanism and nature of forces operating at the boundary 22,23 . Both techniques have some disadvantages (steric factors can 50 influence both grafting density and monomer diffusion to active polymerization sites).…”