The influence of substituents on gelation and stacking order of oligoaramid – based supramolecular networks

Abstract

Self-assembly has proven to be a powerful tool for functional, smart materials such as hydrogels derived from low molecular weight compounds.

Advanced Methods for the Characterization of Supramolecular Hydrogels

“…SAXS is a multi-purpose, universal research tool which aids in the real-time investigation of complex structures while being able to extract structural changes [17,61,62]. The proper visualization of the macromolecular size and shapes of various biological compounds is essential as these directly affect their function.…”

“…SAXS offers a simple way to do this, increasing in use with the advancements of synchrotron X-ray detectors and sources; SAXS is commonly used to investigate supramolecular hydrogels. A few assumptions made in scattering techniques are that the particles used are identical, randomly oriented, and of sufficiently low concentration to prevent scattered wave interference and that a macromolecular solute and homogeneous solvent are used in the analyzed solution [17,61,62]. SAXS is compatible with various biophysical methods and can be used to define 3D structures to more than 15 Å resolution [61,62].…”

“…The length scales associated with the gels' self-assembly processes were analyzed using SAXS, and for three of the four compounds, the SAXS data fit with a cylindrical model. Using SAXS was essential in their experiment as it exposed shortcomings in their molecular dynamics simulations, which aimed at creating a model for molecular level aggregation, by showing an entirely different stacking mechanism forming the aggregates [17]. Thus, SAXS has proven to act as an effective tool to note shapes and structural changes during experimentation, and computational methods such as molecular dynamics provide a useful complement to this experimental technique.…”

“…While we sometimes rely on studies with a broader focus to be able to explain the techniques, in each section we include examples of how these methods have been used with supramolecular hydrogels to specifically illustrate the relevant information that can be obtained from this characterization. [14] with permission, ©2019-Royal Society of Chemistry; (b) from [15] under the terms of a CC-BY license, ©2014-American Chemical Society; (c) from [16] under the terms of the Creative Commons Attribution License, ©2014-the authors and published by Beilstein-Institut; (d) from [17] with permission, ©2019-Royal Society of Chemistry; (e) from [18] with permission, ©2017-Elsevier; and (f) from (i) [19] under the terms of a CC-BY license, ©2020-American Chemical Society and (ii) [20] under the terms of the Creative Commons Attribution License, ©2007-the authors and published by PLoS ONE.…”

Computational Tools to Rationalize and Predict the Self-Assembly Behavior of Supramolecular Gels

“…On the other hand, if the proposed structure is stable, the relative position of the atoms in the structure will have little displacement along the trajectory and an equilibrated structure will be reached. Only supramolecular structures with a certain degree of stability are then considered to analyze plausible stacking modes that might be important during gelation [ 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 ]. The topology of the initial proposed structure is crucial to the value of this method.…”