Increase in the Hydrophilicity and Lewis Acid-Base Properties of Solid Surfaces Achieved by Electric Gliding Discharge in Humid Air: Effects on Bacterial Adherence

This study addressed the effects of treatment with gliding discharge plasma on the surface properties of solid materials, as well as the consequences concerning adherence of a model bacterium. As evaluated by contact angles with selected liquids, plasma treatment caused an increase in surface hydrophilicity and in the Lewis acid-base components of the surface energy of all materials tested. These modifications were more marked for low density polyethylene and stainless steel than for polytetrafiuoroethylene. After treatment, the hydrophilicity of the materials remained relatively stable for at least 20 days. Moreover, analysis of the topography of the materials by atomic force microscopy revealed that the roughness of both polymers was reduced by glidarc plasma treatment. As a result of all these modifications, solid substrates were activated towards micro-organisms and the adherence of S. epidermidis, a negatively charged Lewis-base and mildly hydrophilic strain selected as the model, was increased in almost all the cases tested.

A thin transition film formed by plasma exposure contributes to the germanium surface hydrophilicity

Plasma treatment and 10% NH_4OH solution rinsing were performed on a germanium（Ge） surface.It was found that the Ge surface hydrophilicity after O_2 and Ar plasma exposure was stronger than that of samples subjected to N_2 plasma exposure. This is because the thin Ge Ox film formed on Ge by O_2 or Ar plasma is more hydrophilic than Ge Ox Ny formed by N_2 plasma treatment. A flat（RMS 〈 0：5 nm） Ge surface with high hydrophilicity（contact angle smaller than 3°） was achieved by O_2 plasma treatment, showing its promising application in Ge low-temperature direct wafer bonding.

Severe prelenticular membrane formation on the surface of a hydrophilic acrylic intraocular lens after cataract surgery in an eye with an Ahmed valve implant

【正】Dear Sir,Iam Yong-Sun Ahn,from the Department of Ophthalmology of St.Vincent Hospital of Suwon,Kyungki-do,South Korea.Cataracts are a common problem in eyes with a glaucoma drainage device(GDD),because tube shunt surgery increases the incidence and progression of cataracts[1].An Ahmed valve,the most commonly inserted GDD,is composed of a silicone tube connected to a flat plate sewn to the sclera,and aqueous humor flows from the

Fabrication of Superhydrophobic–Hydrophilic Patterned Cu@Ag Composite SERS Substrate via Femtosecond Laser

Ultralow concentration molecular detection is critical in various fields,e.g.,food safety,environmental monitoring,and dis-ease diagnosis.Highly sensitive surface-enhanced Raman scattering(SERS)based on ultra-wettable surfaces has attracted attention due to its unique ability to detect trace molecules.However,the complexity and cost associated with the preparation of traditional SERS substrates restrict their practical application.Thus,an efficient SERS substrate preparation with high sensitivity,a simplified process,and controllable cost is required.In this study,a superhydrophobic–hydrophilic patterned Cu@Ag composite SERS substrate was fabricated using femtosecond laser processing technology combined with silver plating and surface modification treatment.By inducing periodic stripe structures through femtosecond laser processing,the developed substrate achieves uniform distribution hotspots.Using the surface wettability difference,the object to be measured can be confined in the hydrophilic region and the edge of the hydrophilic region,where the analyte is enriched by the coffee ring effect,can be quickly located by surface morphology difference of micro-nanostructures;thus,greatly improving detec-tion efficiency.The fabricated SERS substrate can detect Rhodamine 6G(R6G)at an extraordinarily low concentration of 10^(−15)mol/L,corresponding to an enhancement factor of 1.53×10^(8).This substrate has an ultralow detection limit,incurs low processing costs and is simple to prepare;thus,the substrate has significant application potential in the trace analysis field.

Constructing Versatile Hydrophilic Surfaces via in-situ Aminolysis

Surface hydrophilization is required for numbers of applications such as biosensor,biomedical implants and marine coating.However,the preparation of hydrophilic surface from a solid substrate still suffers from limited thicknesses,complex procedures,restricted substrates and harsh conditions.Herein,a method based on in-situ aminolysis of poly(pentafluorophenyl acrylate)(pPFPA)capable of generating arbitrary hydrophilic surface is proposed,enabling high design freedom and abundant choices of hydrophilic molecules.Simply immersing pPFPA coated substrates into 3-((3-aminopropyl)dimethylammonio)propane-1-sulfonate(ADPS),β-alanine and amine-terminal poly(ethylene glycol)(NH2-PEG)solutions for two hours drastically reduces the water contact angle of the corresponding surfaces,indicating the high efficiency and excellent generality of such method.Systematical studies reveal that these coatings are able to mitigate fog formation,self-clean the oil contaminant and exhibit excellent antifouling performance against algae.Notably,relying on the fast and quantitative feature of the aminolysis,these hydrophilic surfaces possess excellent regeneration capability and well-recover their hydrophilic feature after being physically damaged.This work represents a facile and universal way to fabricate versatile hydrophilic surfaces for multi-functional applications such as self-cleaning,patterning,sensing,antifogging and anti-biofouling.

Effect of magnesium doping on the light-induced hydrophilicity of ZnO thin films

Undoped and Mg-doped ZnO thin films were deposited on Si（111） and quartz substrates by using the sol-gel method.Microstructure,surface topography and water contact angle of the thin films have been measured by X-ray diffraction（XRD）,an atomic force microscope（AFM） and water contact angle apparatus,respectively. The XRD results show that all the thin films are polycrystalline with a hexagonal structure and have a preferred orientation along the c-axis perpendicular to the substrate.With the increase of Mg concentration,the RMS roughness increases from 2.14 to 9.56 nm and the contact angle of the un-irradiated thin films decreases from 89°to 82°. The wetting behavior of the resulting films can be reversibly switched from hydrophobic to hydrophilic,through alternation of UV illumination and dark storage.The light-induced efficiency of the thin films increases with the increase of Mg concentration.

Hydrophilic carbon nanotube membrane enhanced interfacial evaporation for desalination

Carbon nanotube-based(CNT-based) interfacial evaporation material is one of the most potential materials for solar desalination. Here, we studied the evaporation rate of the CNT-based membranes with different hydrophilic and hydrophobic chemical modified surfaces using molecular dynamic simulations.We found that the hydrogen bonding density among water molecules at the interface is a key factor in enhancing the evaporation rate. For a hydrophilic CNT-based membrane, the strong interactions between the membrane outer surface and the water molecules can destroy the water-water hydrogen bonding interactions at the interface, resulting in the reduction of the hydrogen bonding density, leading to an enhancement effect in evaporation rate. We also found that there is an optimal thickness for evaporation membrane. These findings could provide some theoretical guidance for designing and exploring advanced CNT-based systems with more beneficial performance in water desalination.

INVESTIGATION OF INFLUENCE OF WETTABILITY ON POISEUILLE FLOW VIA MOLECULAR DYNAMICS SIMULATION

In this article,the influence of wettability on a liquid flow between two parallel plane walls were studied by using Non-Equilibrium Molecular Dynamics（NEMD） simulation.The wettability of the solid surfaces can be described as the contact angle.The liquid flow rate,the slip velocity and the slip length which are affected by the contact angle were investigated.The results show that the boundary condition at a microscopic level is different from a ＂no-slip＂ condition at a macroscopic level.There exits a slippage of a liquid flow for the hydrophobic boundary and an external force is needed to overcome threshold pressure for the hydrophilic boundary.And the orderly layered distributions of the liquid particles near the hydrophilic surface vary from a place near the hydrophobic surface.The study indicates that the surface wettability plays a significant role on possibilities of forming a viscous layer and the direct slip at the solid surface.The resistance of liquid flow can be decreased by changing the wettability of boundary surface.