Silver nanoparticles were surface functionalized with diacids and then incorporated into the polymer matrix with silver flakes as conductive fillers. By using appropriate diacids, the resistivity of the silver flakes and nanoparticles (molar ratio of silver flakes to nanoparticles is equal to 6:4) incorporated polymer composites was dramatically reduced to as low as 5 × 10 -6 Ω‚cm. Morphology studies showed that the decreased resistivity resulted from the sintering of silver nanoparticles. The contact resistance of the polymer composites under 85 °C and 85% relative humidity was significantly stable with respect to aging time as a result of the further sintering of silver nanoparticles.

Improvement of the robustness of superhydrophobic surfaces is critical in order to achieve commercial applications of these surfaces in such diverse areas as self-cleaning, water repellency and corrosion resistance. In this study, the mechanical robustness of superhydrophobic surfaces was evaluated on hierarchically structured silicon surfaces. The effect of two-scale hierarchical structures on robustness was investigated using an abrasion test and the results compared to those of superhydrophobic surfaces fabricated from polymeric materials and from silicon that contains only nanostructures. Unlike the polymeric and nanostructure-only surfaces, the hierarchical structures retained superhydrophobic behavior after mechanical abrasion.

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wileyonlinelibrary.comfl exible nature, impossible within the confi nes of rigid and planar substrates. Stretchable RF electronics not only enable applications in which circuits can be wrapped conformally around complex curvilinear shapes or biological tissues, such as in body-worn wireless sensor nodes, [ 1,2 ] and wearable radio frequency identifi cation (RFID) tags, [ 3 ] but also allow facile tuning of the resonant frequency by mechanical deformation. [ 4,5 ] However, the fi eld of stretchable RF electronics is still in its infancy, and like other emerging electronic technologies, new materials and processing methods are the two driving forces for their ever-improving development and performance.There are currently two general approaches to the fabrication of stretchable electronics. The fi rst utilizes conventional rigid materials, but employs elegantly designed wavy or arc-shaped structures that are capable of accommodating applied strains of 100% or more. [ 2,6,7 ] The second approach is to maintain the conventional circuit layout, but embed stretchable or fl owable conductive materials, such as conductive polymers, [ 8,9 ] conductive polymer composites, [ 10 ] and liquid metal alloys [ 4,11 ] as stretchable conduction lines. For antennas, this second approach is usually preferred because of its relative simplicity in circuit design and fabrication. However, this approach imposes stringent requirements for the conductive materials, including 1) high electrical conductivity to achieve high-effi ciency for the RF devices; [ 9 ] and 2) high elasticity to provide a tunable resonant frequency, [ 4 ] and 3) maintaining a similar electrical conductivity under applied strain. Conductive polymers and carbon-based conductive composites have conductivities at least three orders of magnitude lower than those of metals, leading to an inferior electrical effi ciency values; [ 9 ] and liquid metal alloys usually present the fundamental problems of a high freezing temperature (limiting their usage in cold weather), thermal expansion coeffi cient mismatch with dielectric substrates, and a tendency towards leakage. [ 4 ] Here we report the use of stretchable silicone-based electrically conductive adhesives (silo-ECAs) as conductor and pure silicone elastomers as substrate for the fabrication of stretchable antennas. Silicone rubbers feature a unique combination of high elasticity, biocompatibility, [ 12 ] patternability, [ 13 ] and low Stretchable radio-frequency electronics are gaining popularity as a result of the increased functionality they gain through their fl exible nature, impossible within the confi nes of rigid and planar substrates. One approach to fabricating stretchable antennas is to embed stretchable or fl owable conductive materials, such as conductive polymers, conductive polymer composites, and liquid metal alloys as stretchable conduction lines. However, these conductive materials face many challenges, such as low electrical conductivity under mechanical deformation and delamination from substrates. I...