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Creating thin (<100 nm) hydrophobic coatings that are durable in wet conditions remains challenging. Although the dropwise condensation of steam on thin hydrophobic coatings can enhance condensation heat transfer by 1000%, these coatings easily delaminate. Designing interfaces with high adhesion while maintaining a nanoscale coating thickness is key to overcoming this challenge. In nature, cell membranes face this same challenge where nanometer-thick lipid bilayers achieve high adhesion in wet environments to maintain integrity. Nature ensures this adhesion by forming a lipid interface having two nonpolar surfaces, demonstrating high physicochemical resistance to biofluids attempting to open the interface. Here, developing an artificial lipid-like interface that utilizes fluorine−carbon molecular chains can achieve durable nanometric hydrophobic coatings. The application of our approach to create a superhydrophobic material shows high stability during jumping-droplet-enhanced condensation as quantified from a continual one-year steam condensation experiment. The jumping-droplet condensation enhanced condensation heat transfer coefficient up to 400% on tube samples when compared to filmwise condensation on bare copper. Our bioinspired materials design principle can be followed to develop many durable hydrophobic surfaces using alternate substrate-coating pairs, providing stable hydrophobicity or superhydrophobicity to a plethora of applications.

2S-soy protein, a biopolymer extracted from soy protein isolate (2S-SPI), was studied as a non-covalent surfactant for polymer nanocomposites. This study showed that 2S-SPI effectively improved carbon nanofibers (CNFs) dispersion in poly(vinylidene fluoride). 2S-SPI surfactant had remarkable impact on both electrical conduction and dielectric relaxation of the nanocomposites, particularly, at high temperatures. 2S-SPI modified CNFs caused coupling of conductivity relaxation and structural relaxations of the nanocomposites, in contrast to pristine CNFs. Both Maxwell-Wagner-Sillars and conductivity relaxations were enhanced at high temperatures by 2S-SPI, which made different contributions to electrical conduction of the nanocomposites with or without surface modification.

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In this paper, a metasurface (MS) is designed based on the hybrid array pattern synthesis and particle swarm optimization method for wideband monostatic and multistatic radar stealth. The non-absorptive MS is composed of two kinds of electronic band gap structures with the reflection phase difference of 180° (±37°) over a wide frequency range. Far field scattering pattern of the MS can be quickly and accurately synthetized by the method of moments and array pattern synthesis. A new strategy is proposed for realizing the diffusion reflection of electromagnetic waves by redirecting electromagnetic energies to more directions through optimizing the reflected phase arrangement for the MS by hybrid array pattern synthesis and particle swarm optimization algorithm. Due to the non-uniform distributions of phase gradient between neighboring lattices, numerous scattering lobes are produced in the upper half-space, leading to a great reduction of bistatic radar cross section (RCS). The −10 dB RCS reduction bandwidth of 80.2% is achieved for both monostatic and bistatic at normal incidence. The specular reflection and bistatic scattering for oblique incidence with TE and TM polarizations are also considered in detail. The measured results are in good agreement with the corresponding simulations.

This work reports a three-dimensional (3D) radio frequency L−C filter network enabled by a CMOS-compatible two-dimensional (2D) fabrication approach, which combines inductive (L) and capacitive (C) self-rolled-up membrane (S-RuM) components monolithically into a single L−C network structure, thereby greatly reducing the on-chip area footprint. The individual L−C elements are fabricated in-plane using standard semiconductor processing techniques, and subsequently triggered by the built-in stress to self-assemble and roll into cylindrical air-core architectures. By designing the planar structure geometry and constituent layer properties to achieve a specific number of turns with a desired inner diameter when the device is rolled up, the electrical characteristics can be engineered. The network layouts of the L and C components are also reconfigurable by selecting appropriate input, output, and ground contact routing topographies. The devices demonstrated here operate over the range of ≈1−10 GHz. Their area and volume footprints are ≈0.09 mm 2 and ≈0.01 mm 3 , respectively, which are ≈10× smaller than most of the comparable conventional filter designs. These S-RuM-enabled 3D microtubular L−C filter networks represent significant advancement for miniaturization and integration of passive electronic components for applications in mobile connectivity and other frequency range.