Architecture of Supramolecular Soft Functional Materials: From Understanding to Micro‐/Nanoscale Engineering

Abstract

This article gives an overview of the current progress of a class of supramolecular soft materials consisting of fiber networks and the trapped liquid. After discussing the up‐to‐date knowledge on the types of fiber networks and the correlation to the rheological properties, the gelation mechanism turns out to be one of the key subjects for this review. In this concern, the following two aspects will be focused upon: the single fiber network formation and the multi‐domain fiber network formation of this type of material. Concerning the fiber network formation, taking place via nucleation, and the nucleation‐mediated growth and branching mechanism, the theoretical basis of crystallographic mismatch nucleation that governs fiber branching and formation of three‐dimensional fiber networks is presented. In connection to the multi‐domain fiber network formation, which is governed by the primary nucleation and the subsequent formation of single fiber networks from nucleation centers, the control of the primary nucleation rate will be considered. Based on the understanding on the the gelation mechanism, the engineering strategies of soft functional materials of this type will be systematically discussed. These include the control of the nucleation and branching‐controlled fiber network formation in terms of tuning the thermodynamic driving force of the gelling system and introducing suitable additives, as well as introducing ultrasound. Finally, a summary and the outlook of future research on the basis of the nucleation‐growth‐controlled fiber network formation are given.

A High‐Performance and Fully Recyclable Supramolecular Nanofibrous Membrane for Multifunctional Air Filtration

“…Given the critical role of microstructure in determining the performance attributes of GO@MA·TMA membranes, a comprehensive microstructural characterization was conducted using SEM to elucidate the morphological evolution of membranes (Figure 2a–e ). The pristine MA·TMA membrane consisted of randomly oriented, smooth‐surfaced nanocrystalline fibers (Figure 2a ), consistent with prior observations of self‐assembly branching phenomena [ 24 , 32 ]. In contrast, the GO nanosheets (Figure 2f ), possessing a characteristic 2D geometry and high specific surface area essential for PM capture [ 40 ], induced a significant microstructure transformation of the membrane.…”

Salicylato Titanocene Complexes as Cooperative Organometallic Lewis Acid and Brønsted Acid Catalysts for Three‐Component Mannich Reactions

“…As expected, the slow‐cooled gels possessed longer fibers than the fast‐cooled ones 8a. The degree of supersaturation (and, thus, the thermodynamic driving force for phase separation) during the nucleation and fiber growth processes is smaller during slow cooling, and the frequency of crystallization mismatches, leading to branching and shorter fibers, is reduced in the final SAFiN 2b. c Furthermore, both fast‐ and slow‐cooled gels of trans ‐13,14‐diol in nitrobenzene are more translucent and have the smallest objects among the three diols for which gels were found, while both fast‐ and slow‐cooled gels of trans ‐9,10‐diol in nitrobenzene are opaque and have the largest objects.…”

Direct Growth of Microspheres on Amorphous Precursor Domains in Polymer-Controlled Crystallization of Indomethacin

“…Microspheres, achieved by using ethanol (or dimethyl sulfoxide – DMSO) and water as the good and poor solvents, respectively, are composed of the radially aligned and interwoven nanofibers as structural subunits (Figure a). The spherulitic form, a representative form via a far-from-equilibrium process observable in a number of crystallization studies, was obtained due to the fast increase of the supersaturation in the antisolvent precipitation. − The precipitation follows the classical nucleation–growth process, as being detected in situ under the optical microscope (Figure s1; OM), in line with the existing viewpoint . Specifically, the dissolution–recrystallization occurred in the microspheres in the alcoholic–aqueous dispersion mixture to achieve the INN submicrofibers after 7 days (Figure b and Figure s2) in an Ostwald ripening process.…”