Characterization of Ti-Cu Films Deposited by HPPMS and Effect on NO Catalytic Release and Platelet Adhesion Behavior

Ti-Cu films with different Cu concentrations were fabricated by high-power pulsed magnetron sputtering（HPPMS） to release copper ions and catalyze NO to improve the blood compatibility. The Cu concentrations of films were 25.7 at% and 68.8 at%. Pure Ti films were also fabricated. Copper release, catalytic release of nitric oxide（NO）, and blood platelet adhesion of Ti-Cu films were studied. Ti-Cu films released copper ions in PBS solution and more Cu ions were released from films with 68.8 at% Cu. Ti-Cu films had excellent ability of catalytical decomposition of exogenous donor S-nitroso-N-acetyl-DL-penicillamine（SNAP） and as a result, nitric oxide（NO） was generated. The NO generation catalyzed by Ti-Cu films was significantly higher than that by pure Ti films. This was more eminent in the Ti-Cu films with 68.8 at% Cu. The platelet adhesion and activation of Ti-Cu films were significantly inhibited compared to that of pure Ti films in the presence of SNAP. The Ti-Cu film fabricated by HPPMS showed the ability of releasing Cu ions to catalyze SNAP to generate NO to inhibit platelet adhesion and activation.

ADHESION STRENGTH OF COATING SUBSTRATE AND SURFACE MORPHOLOGY OF PRETREATMENT

Premature failure of coated tool often results from a poor adhesion of coating-substrate and shortens the lifetime of the tool. The results of increasing the adhesion strength of thin film coatings on cutting tool inserts by pretreating the inserts with sandblasting technique to obtain a desirable surface morphology of the inserts are presented. A geometric model representing the ideal surface morphology is established to enhance the nucleation density and adhesion strength of coating-substrate. Thin film coating experiment is conducted on the substrates of four different sample groups. Indentation and wear tests are performed on coated inserts to evaluate the effect of sandblasting on the adhesion strength of the coatings. A theoretical analysis is provided on the formation and growth of atom clusters in terms of the contact angle and the thermodynamic barrier of a substrate to predict thin film nucleation.

Polypropylene non-woven supported fibronectin molecular imprinted calcium alginate/polyacrylamide hydrogel film for cell adhesion

Fibronectin （FN） imprinted polypropylene （PP） non-woven supported calcium alginate/polyacrylamide hydrogel film （PP-s-CA/PAM MIP） was prepared using non-woven PP fiber as matrix, FN as template molecule, sodium alginate （SA） and acrylamide （AM） as functional monomers, via UV radiation-reduced polymerization. The PP-s-CA[PAM MIP exhibited an obvious improvement in terms of adsorption capacity for FN compared with non-imprinted polymer （NIP）. The PP-s-CA/PAM MIP was successfully used for the culture of mouse fibroblast cells （L929） and the results showed that PP-s-CA]PAM MIP exhibited better cell adherence performance than the NIP did.

Effect of Axial Magnetic Field on the Microstructure and Mechanical Properties of CrN Films Deposited by Arc Ion Plating

CrN films were deposited on the high-speed-steel substrates by arc ion plating. The effect of an axial magnetic field on the microstructure and mechanical properties was investigated. The chemical composition, microstructure, surface morphology, surface roughness, hardness and film/substrate adhesion of the film were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscope（SEM）, surface morphology analyzer, Vickers microhardness test and scratch test. The results showed that the magnetic field puts much effect on the microstructure,chemical composition, hardness and film/substrate adhesion of the Cr N films. The N content increases and Cr content decreases when the magnetic flux density increases from 0 to 30 m T. All of the Cr N films were found to be substoichiometric. With an increase in the magnetic flux density, the film structures change in such way： Cr_2N →Cr_（2-N）＋CrN→CrN＋Cr_2N→CrN.The SEM results showed that the number of macroparticles（MPs） on the film surface is significantly reduced when the magnetic flux density increases to 10 mT or higher. The surface roughness decreases with the magnetic field, which is attributed to the fewer MPs and sputtered craters on the film surface. The hardness value increases from 2074 HV_（0.025） at 0 mT（without magnetic field） and reaches a maximum value of 2509 HV_（0.025） at 10 m T.The further increase in the magnetic flux density leads to a decrease in the film hardness. The critical load of film/substrate adhesion shows a monotonous increase with the increase in magnetic flux density.

Improvement in the Adhesion Between Electrode of a SOFC and Ag Paste as a Current Collector by Au Deposition

This paper reports the use of Au films to improve the performance of the stacked solid oxide fuel cell(SOFC) based on the characterization of the interface and the adhesion between the electrodes of the SOFCs and the Ag paste. The specimens were manufactured to perform the experiment as follows. A Si O2 wafer with a 300 mm notch was attached to the electrodes of a SOFC by a Ag paste and Au film, which were deposited on the electrodes by sputtering for 1 min or 5 min deposition time and annealed at300 C for 1 h. The four-point bending test was performed, which resulted in the formation of an extended crack at the tip on the wafer notch, and the crack propagation was observed using a stereo microscope equipped with a charge-coupled device(CCD). Consequently, the interfacial adhesion energy and the effect of the Au film between the each electrode and the Ag paste can be evaluated. On the cathode, the interfacial adhesion energy without Au film was 2.59 J/m2(upper value) and the adhesion energy increased to 11.59 J/m2(upper value) and 15.89 J/m2(lower value) with the Au film. On the anode,the interfacial adhesion energy without Au film was 1.74 J/m2(upper value), which increased to 11.07 J/m2(upper value) and 14.74 J/m2(lower value) with the Au film. In addition, the interface areas were analyzed by scanning electron microscopy(SEM) and energy dispersive spectroscopy(EDS) to estimate the interface delamination.

An update on electrostatic powder coating for pharmaceuticals

Derived from dry powder coating of metals, electrostatic powder coating for pharmaceuticals is a technology for coating drug solid dosage forms. In this technology, coating powders, containing coating polymers, pigments, and other excipients, are directly sprayed onto the surface of the solid dosage forms through an electrostatic gun without using any organic solvent or water. The deposited coating powders are further cured to form a coating film. Electrostatic powder coating technology has many advantages compared to other pharmaceutical coating methods. It can eliminate the limitations caused by the organic solvent in solvent coating such as environmental issues and health problems. And electrostatic powder coating technology also surpasses aqueous coating due to its shorter processing time and less energy consumption, leading to a lower overall cost. Furthermore, the utilization of electrical attraction can promote the movement of coating powders towards the substrate, leading to an enhanced coating powder adhesion and coating efficiency, which make it more promising compared to other dry coating technologies. The objective of this review is to summarize the coating principles, apparatus, and formulations of different electrostatic powder coating technologies, giving their advantages and limitations and also analyzing the future application in the industry for each technology

Mechanically robust antireflective coatings

Mechanical strength is an essential parameter that influences and limits the lifetime performance of antireflective （AR） coatings in optical devices. Speciflcally, amphiphobic AR coatings with reduced reflectance are of great significance as they considerably enlarge the range of fundamental applications. Herein, we describe the design and fabrication of amphiphobic AR coatings with reduced reflectance and enhanced mechanical resilience. Introducing a thin polytetrafluoroethylene （PTFE） layer on top of the bilayer SiOz coating via vapor deposition method makes it highly liquid repellent. We achieved reduced reflectance （〈 1%） over the entire visible wavelength range, as well as tunability according to the desired wavelength region. The fabricated film showed better thermal stability （up to 300℃） with stable AR efficiency, when an ultrathin dense coat of Al2O3 was deposited via atomic layer deposition （ALD） on the polymer-based bilayer SiO2 antireflective coating （P-BSAR）. The experimental results prove that the omnidirectional AR coating in this study exhibits multifunctional properties and should be suitable for the production of protective optical equipment and biocompatible polymer films for the displays of portable electronic devices.