As is frequently seen in sci-fi movies, future electronics are expected to ultimately be in the form of wearable electronics. To realize wearable electronics, the electric components should be soft, fl exible, and even stretchable to be human-friendly. An important step is presented toward realization of wearable electronics by developing a hierarchical multiscale hybrid nanocomposite for highly fl exible, stretchable, or transparent conductors. The hybrid nanocomposite combines the enhanced mechanical compliance, electrical conductivity, and optical transparency of small CNTs (d ≈ 1.2 nm) and the enhanced electrical conductivity of relatively bigger Ag nanowire (d ≈ 150 nm) backbone to provide effi cient multiscale electron transport path with Ag nanowire current backbone collector and local CNT percolation network. The highly elastic hybrid nanocomposite conductors and highly transparent fl exible conductors can be mounted on any non-planar or soft surfaces to realize human-friendly electronics interface for future wearable electronics.

A new structure of flexible transparent electrodes is reported, featuring a metal mesh fully embedded and mechanically anchored in a flexible substrate, and a cost-effective solution-based fabrication strategy for this new transparent electrode. The embedded nature of the metal-mesh electrodes provides a series of advantages, including surface smoothness that is crucial for device fabrication, mechanical stability under high bending stress, strong adhesion to the substrate with excellent flexibility, and favorable resistance against moisture, oxygen, and chemicals. The novel fabrication process replaces vacuum-based metal deposition with an electrodeposition process and is potentially suitable for high-throughput, large-volume, and low-cost production. In particular, this strategy enables fabrication of a high-aspect-ratio (thickness to linewidth) metal mesh, substantially improving conductivity without considerably sacrificing transparency. Various prototype flexible transparent electrodes are demonstrated with transmittance higher than 90% and sheet resistance below 1 ohm sq(-1) , as well as extremely high figures of merit up to 1.5 × 10(4) , which are among the highest reported values in recent studies. Finally using our embedded metal-mesh electrode, a flexible transparent thin-film heater is demonstrated with a low power density requirement, rapid response time, and a low operating voltage.

Polymer nanocomposites with inclusion of ceramic nanofillers have relatively high yield strength, elastic moduli, and toughness that therefore are widely used as functional coating and films for optoelectronic applications. Although the mechanical properties are enhanced with increasing the fraction of nanofiller inclusion, there generally is an upper limit on the amount of nanofiller inclusion because the aggregation of the fillers in the polymer matrix, which typically occurs, degrades the mechanical and/or optical performances above 5 vol % of inclusions. Here, we demonstrate an unconventional polymer nanocomposite composed of a uniformly distributed three-dimensional (3D) continuous ceramic nanofillers, which allows for extremely high loading (∼19 vol %) in the polymer matrix without any concern of aggregation and loss in transparency. The fabrication strategy involves conformal deposition of AlO nanolayer with a precise control in thickness that ranges from 12 to 84 nm on a 3D nanostructured porous polymer matrix followed by filling the pores with the same type of polymer. The 3D continuous AlO nanolayers embedded in the matrix with extremely high filler rate of 19.17 vol % improve compressive strength by 142% compared to the pure epoxy without AlO filler, and this value is in agreement with theoretically predicted strength through the rule of mixture. These 3D nanocomposites show superb transparency in the visible (>85% at 600 nm) and near-IR (>90% at 1 μm) regions and improved heat dissipation beyond that of conventional AlO dispersed nanocomposites with similar filler loading of 15.11 vol % due to the existence of a continuous thermal conduction path through the oxide network.

No abstract

We present a novel method of fabricating superhydrophobic and superoleophobic surfaces with nanoscale reentrant curvature by nanotransfer molding and controlled wet etching of the facile undercut. This method produces completely ordered re-entrant nanostructures and prevents capillary-induced bundling effects. The mushroom-like, re-entrant, overhanging structure demonstrates superhydrophobic and superoleophobic characteristics, as tested by water droplet bouncing and contact angle measurements, and has high transparency on a flexible substrate. Widespread use as self-cleaning surfaces is expected in the near future.

No abstract

A large theoretical charge storage capacity along with a low discharge working potential renders silicon a promising anode material for high energy density lithium ion batteries. However, up to 400% volume expansion during charge-discharge cycling coupled with a low intrinsic electronic conductivity causes pulverization and fracture, thus inhibiting silicon's widespread use in practical applications. We report herein on a low cost approach to fabricate hybrid silicon nanowire (SiNW)/graphene nanostructures that exhibit enhanced cycle performance with the capability of retaining more than 90% of their initial capacity after 50 cycles. We also demonstrate the use of hot-pressing in the absence of any common polymer binder such as PVDF to bind the hybrid structure to the current collector. The applied heat and pressure ensure strong adhesion between the SiNW/graphene nano-composite and current collector. This facile yet strong binding method is expected to find use in the further development of polymer-binder free anodes for lithium ion batteries.

Mass-producible superhydrophobic surfaces with remarkably identical appearance and efficiency through a mold fabrication and hot embossing process are reported.