Structured Ultra‐Flyweight Aerogels by Interfacial Complexation: Self‐Assembly Enabling Multiscale Designs

Abstract

The rapid co‐assembly of graphene oxide (GO) nanosheets and a surfactant at the oil/water (O/W) interface is harnessed to develop a new class of soft materials comprising continuous, multilayer, interpenetrated, and tubular structures. The process uses a microfluidic approach that enables interfacial complexation of two‐phase systems, herein, termed as “liquid streaming” (LS). LS is demonstrated as a general method to design multifunctional soft materials of specific hierarchical order and morphology, conveniently controlled by the nature of the oil phase and extrusion's injection pressure, print‐head speed, and nozzle diameter. The as‐obtained LS systems can be readily converted into ultra‐flyweight aerogels displaying worm‐like morphologies with multiscale porosities (micro‐ and macro‐scaled). The presence of reduced GO nanosheets in such large surface area systems renders materials with outstanding mechanical compressibility and tailorable electrical activity. This platform for engineering soft materials and solid constructs opens up new horizons toward advanced functionality and tunability, as demonstrated here for ultralight printed conductive circuits and electromagnetic interference shields.

Functional Janus liquids

“…Liquid streaming is a new process where a jetted stream of one liquid in an external immiscible liquid can be stabilized by interfacial jamming, forming tubular liquid threads 1,5,13 . For the e cient generation of these tubular all-liquid structures, the rate of NPSs formation, assembly, and jamming must be faster than the relaxation of uids, while their binding energy must be high enough to impart mechanical stability 14,15,16 .…”

“…For the e cient generation of these tubular all-liquid structures, the rate of NPSs formation, assembly, and jamming must be faster than the relaxation of uids, while their binding energy must be high enough to impart mechanical stability 14,15,16 . This process generates a tubular skin around the jetted liquid threads that maintains the integrity of this class of structured liquids 1,5,15 . Taking advantage of liquid jetting, several new concepts of structured liquids, e.g., all-liquid 3D printing 15,16,17 and 3D water in oil tubular emulsions with tunable morphology and domain size 5 , were put forward.…”

“…This process generates a tubular skin around the jetted liquid threads that maintains the integrity of this class of structured liquids 1,5,15 . Taking advantage of liquid jetting, several new concepts of structured liquids, e.g., all-liquid 3D printing 15,16,17 and 3D water in oil tubular emulsions with tunable morphology and domain size 5 , were put forward. But, so far, little advantage has been taken from the combination of functional NPs and liquid streaming to generate constructs with a speci c function in soft robotics 18 , micro uidics 15,19,20 , or sensing 17,21 .…”

“…1a, S6a-b, and Video S1). Here, the rapid co-assembly of GO and POSS at the interface forms an interfacial skin that wraps the jetted liquid thread 5,16 . This interfacial skin prevents the jet from breaking up into droplets, suppressing Plateau-Rayleigh instabilities 1,4 .…”

Hollow Gradient-Structured Iron-Anchored Carbon Nanospheres for Enhanced Electromagnetic Wave Absorption

“…Recent years have been seen enormous efforts to designing a structure in multi-scales to acquire the ideal physical properties simultaneously [19][20][21][22]. Especially, combining gradient structures with others is considered to be an ideal method to solve the problems of multi-target, for the excellent "absorption-reflection-reabsorption" effect and eminent intensifying of incidence microwave [15,23].…”