Poly(N,N-diethylacrylamide)-endowed spontaneous emulsification during the breath figure process and the formation of membranes with hierarchical pores.

The spontaneous emulsification for the formation of water-in-oil (W/O) or oil-in-water (O/W) emulsions needs the help of at least one kind of the third component (surfactant or cosolvent) to stabilize the oil-water interface. Herein, with the water/CS2-soluble polymer poly(N,N-diethylacrylamide) (PDEAM) as a surfactant, the spontaneous formation of water-in-PDEAM/CS2 emulsions is reported for the first time. The strong affinity between PDEAM and water or the increase of PDEAM concentration will accelerate the emulsification process with high dispersed phase content. It is demonstrated that the spontaneous emulsification of condensed water droplets into the PDEAM/CS2 solution occurs during the breath figure process, resulting in porous films with two levels of pore sizes (i.e., micron and submicron). The emulsification degree and the amounts of submicron-sized pores increase with PDEAM concentration and solidifying time of the solution. This work brings about incremental interest in spontaneous emulsification that may happen during the breath figure process. The combination of these two simultaneous processes provides us with an option to build hierarchically porous structures with condensed and emulsified water droplets as templates. Such porous membranes may have great potential in fields such as separation, cell culture, and biosensing.

Supergravity-Steered Generic Manufacturing of Nanosheets-Embedded Nanocomposite Hydrogel with Highly Oriented, Heterogeneous Architecture.

Designing nanocomposite hydrogels with oriented nanosheets has emerged as a promising toolkit to achieve preferential performances that go beyond their disordered counterparts. Although current fabrication strategies via electric/magnetic force fields have made remarkable achievements, they necessitate special properties of nanosheets and suffer from an inferior orientation degree of nanosheets. Herein, a facile and universal approach is discovered to elaborate MXene-based nanocomposite hydrogels with highly oriented, heterogeneous architecture by virtue of supergravity to replace conventional force fields. The key to such architecture is to leverage bidirectional, force-tunable attributes of supergravity containing coupled orthogonal shear and centrifugal force field for steering high-efficient movement, pre-orientation, and stacking of MXene nanosheets in the bottom. Such a synergetic effect allows for yielding heterogeneous nanocomposite hydrogels with a high-orientation MXene-rich layer (orientation degree, f = 0.83) and a polymer-rich layer. The authors demonstrate that MXene-based nanocomposite hydrogels leverage their high-orientation, heterogeneous architecture to deliver an extraordinary electromagnetic interference shielding effectiveness of 55.2 dB at 12.4 GHz yet using a super-low MXene of 0.3 wt%, surpassing most hydrogels-based electromagnetic shielding materials. This versatile supergravity-steered strategy can be further extended to arbitrary nanosheets including MoS2, GO, and C3N4, offering a paradigm in the development of oriented nanocomposites.