Polymer nanocomposites (PNCs) are important materials that are widely used in many current technologies and potentially have broader applications in the future due to their excellent property tunability, light weight, and low cost. However, expanding the limits in property enhancement remains a fundamental scientific challenge. Here, we demonstrate that well-dispersed, small (diameter ∼1.8 nm) nanoparticles with attractive interactions lead to unexpectedly large and qualitatively different changes in PNC structural dynamics in comparison to conventional nanocomposites based on particles of diameters ∼10-50 nm. At the same time, the zero-shear viscosity at high temperatures remains comparable to that of the neat polymer, thereby retaining good processability and resolving a major challenge in PNC applications. Our results suggest that the nanoparticle mobility and relatively short lifetimes of nanoparticle-polymer associations open qualitatively different horizons in the tunability of macroscopic properties in nanocomposites with a high potential for the development of advanced functional materials.

A mechanically robust, ultra-elastic foam with controlled multi-scale architectures, tunable mechanical/conductive performance has been fabricated via 3D printing. Hierarchical porosity, including both macro-and micro-scaled pores, are produced by the combination of direct ink writing (DIW), acid etching and phase inversion. The thixotropic inks in DIW are formulated by a simple one-pot process to disperse duo nanoparticles (nanoclay and silica nanoparticles) in a polyurethane suspension. The resulting lightweight foam exhibits This article is protected by copyright. All rights reserved. 2 tailorable mechanical strength, unprecedented elasticity (standing over 1,000 compression cycles), and remarkable robustness (rapidly and fully recover after a load more than 20,000 times of its own weight). Surface coating of CNT affords a conductive elastic foam that can be used as piezoresisitivity sensor with high sensitivity. For the first time, this strategy achieves 3D printing of elastic foam with controlled multi-level 3D structures and mechanical/conductive properties. Moreover, the facile ink preparation method can be utilized to fabricate foams of various materials with desirable performance via 3D printing.

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Confining Zn plating and stripping in a robust and conductive 3D carbon nanotube network results in an electrode, which shows excellent reversibility at high depth of discharge and enables zinc-ion batteries with high-rate and long-term performance.