Anti-fogging/dry-dust transparent superhydrophobic surfaces based on liquid-like molecule brush modified nanofiber cluster structures.

Transparent protective coatings capable of preventing fog and dust accumulation have broad application prospect in photovoltaic systems, optical devices and consumer electronics. Although a number of superhydrophobic coatings have been developed for self-cleaning purpose over the past three decades, there is still a lack of surfaces that can simultaneously possess high transparency, remarkable superhydrophobicity, and excellent fog and dust resistance. In this study, we have prepared surfaces featuring sub-wavelength nanofiber cluster structures through a facile plasma etching method, and further modified the surface with liquid-like perfluoropolyether (PFPE) brushes. The prepared PFPE modified nanofibrous surface (PFPE-NS) exhibits superior optical transparency (transmittance 90.4 % ± 0.7 %) and water repellency, with a water contact angle as high as 171.0° ± 0.6° and sliding angle down to 0.5° ± 0.1° (5 µL). More importantly, benefitted from the nanofiber cluster structures and the slippery liquid-like surface chemistry, the adhesion and accumulation of fog droplets and dust particles on PFPE-NS is greatly inhibited. As a consequence, PFPE-NS can keep excellent optical clearness after 2 h fogging test and maintain an average transmittance above 87 % after 24 h dusting test. Our study provides a promising strategy through constructing liquid-like nanofibrous coating for optical protection that could be applicable in practical rainy, foggy, and dusty environments.

Whether and When Superhydrophobic/Superoleophobic Surfaces Are Fingerprint Repellent.

Driven by the ever-increasing demand for fingerprint-resistant techniques in modern society, numerous researches have proposed to develop innovative antifingerprint coatings based on superhydrophobic/superoleophobic surface design. However, whether superhydrophobic/superoleophobic surfaces have favorable repellency to the microscopic fingerprint is in fact an open question. Here, we establish a reliable method that enables evaluating the antifingerprint capability of various surfaces in a quantitative way. We show that superhydrophobicity is irrelevant with fingerprint repellency. Regarding superoleophobic surfaces, two distinct wetting states of microscopic fingerprint residues, i.e., the "repellent" and the "collapsed" states, are revealed. Only in the "repellent" state, in which the fingerprint residues remain atop surface textures upon being pressed, superoleophobic surfaces can bring about favorable antifingerprint repellency, which correlates positively with their receding contact angles. A finger-deformation-dependent intrusion mechanism is proposed to account for the formation of different fingerprint wetting states. Our findings offer important insights into the mechanism of fingerprint repellency and will help the design of high-performance antifingerprint surfaces for diverse applications.

A versatile colloidal Janus platform: surface asymmetry control, functionalization, and applications.

We show a facile synthetic route towards colloidal SiO2-based Janus particles with tunable asymmetries and functionalities based on the integrated use of silane mixtures, Pickering emulsions, and polydopamine chemistry. We demonstrate the generic nature of the concept and application potential by presenting several functionalities.

Bioinspired synthesis of polydopamine/Ag nanocomposite particles with antibacterial activities.

Mussel-inspired chemistry (polydopamine) offers great opportunities to develop inexpensive and efficient process for many types of materials with complex shapes and functions in a mild and friendly environment. This paper describes a facile, yet green approach to synthesize polydopamine/silver (PDA/Ag) nanocomposite particles with a combination use of polydopamine chemistry and electroless metallization of Ag. In this approach, monodisperse spherical polydopamine particles are first synthesized by the oxidation and self-polymerization of dopamine (monomer) in an alkaline water-ethanol solution at room temperature, which are served as the active templates for secondary reactions due to the abundant catechol and amine groups on the surface. Subsequently, the silver precursor-[Ag(NH3)2](+) ions introduced are easily absorbed onto the surface of the PDA particles, and are immediately in situ reduced to metallic Ag nanoparticles with the help of these active catechol and amine groups. During the preparation, no additional reductants, toxic reagents and intricate instruments are needed. These as-synthesized PDA/Ag nanocomposite particles are ideal candidates for antibacterial application because they do not show significant cytotoxicity against HEK293T human embryonic kidney cells in the in vitro cytotoxicity assay, whereas demonstrate enhanced antibacterial abilities against Escherichia coli (Gram-negative bacteria) and Staphylococcus aureus (Gram-positive bacteria) in the antibacterial assays. Owing to their excellent cytocompatibilities and antibacterial activities, these PDA/Ag nanocomposite particles can be considered as the promising antibacterial materials for future biomedical applications.

Comparison of the cardiovascular impacts of transnasal versus transoral gastroscopy in the aged patients with or without hypertension.

BACKGROUND/AIMS: The cardiovascular impacts of gastroscopy in the aged patients are not neglectable, especially for those with hypertension. The aim of this study was to evaluate the different cardiovascular impacts of transnasal and transoral gastroscopy in the aged patients with or without hypertension. METHODS: 120 aged patients (age >65 years) who had gastroscopy indication were recruited. Transnasal or transoral gastroscopy was employed for each subject. Heart rate (HR), blood pressure (BP), blood oxygen saturation (SaO2) and electrocardiogram (ECG) were recorded. RESULTS: In those patients with normal-tension during transoral gastroscopy examination, HR and BP increased and SaO, decreased, about 1/3-1/2 patients exhibited ECG changes of sinus tachycardia, ectopic rhythm and myocardial ischemia. The changes of HR and BP were more marked in those patients with hypertension during transoral gastroscopy examination, and a greater proportion of patients exhibited the above ECG changes. The maximal increment of HR, systolic BP, diastolic BP and SaO2, as well as ECG changes, significantly decreased in those hypertension patients during transnasal gastroscopy compared with those during transoral gastroscopy, and these changes remained similar to those normal-tension patients during transoral gastroscopy examination. CONCLUSIONS: The cardiovascular impacts of transoral gastroscopy in the aged patients are not neglectable, transnasal gastroscopy examination, the cardiovascular impacts of which are smaller, is relatively safe for those aged hypertension patients.