脉冲电沉积制备HA/ZrO2纳米复合涂层的稳定性及生物相容性评价

采用脉冲电化学沉积法成功地在生物医用钛金属表面制备出均匀的纳米HA/ZrO₂复合涂层. 通过热处理提高涂层的致密性, 同时保留涂层的微纳结构. 考察了热处理后复合涂层的成分、形貌、生物相容性及生理稳定性. X射线衍射分析表明, 复合涂层成分为HA和ZrO₂. 扫描电镜观察发现, 热处理后复合涂层的致密性有所提高. 研究发现, ZrO₂的加入大大降低了HA/ZrO₂复合涂层中钙离子的释放速度, 提高了HA/ZrO₂复合涂层的生理稳定性. 纳米划痕实验结果表明, HA/ZrO₂复合涂层具有较好的结合强度. 通过培养成骨细胞考察了复合涂层的生物相容性. Alamar Blue检测表明, HA/ZrO₂复合涂层表面细胞黏附及增殖能力较好. ALP检测发现, 热处理后HA/ZrO₂复合涂层表面的细胞分化能力较强. 综合细胞培养结果显示, HA/ZrO₂复合涂层有较好的生物相容性.     

Formation of Anatase Nanocrystals-Precipitated Silica Coatings on Plastic Substrates by the Sol-Gel Process with Hot Water Treatment

Anatase nanocrystals-precipitated silica coatings were formed on plastic substrates such as poly(ethylene terephtalate) (PET), acrylic resin (AC) and polycarbonate (PC) from silica-titania gel coatings with and without addition of poly(ethylene glycol) (PEG) by hot water treatment. The maximum thickness of the coatings which can be formed without cracking or peeling-off was 100 to 200 nm for PET and PC substrates, whereas it was less than 50 nm for AC substrates. After a hot water treatment at 90°C for 120 min, the size of the anatase nanocrystals increased to be 30 and 50 nm for the coatings obtained with and without PEG, respectively. Anatase nanocrystals were formed throughout the whole of the coatings obtained with PEG and were formed only on the surface of the coatings obtained without PEG. Both coatings obtained with and without PEG were highly transparent. The plastic substrates with coatings obtained without PEG showed good weathering resistance owing to the protective effects of the residual silica under-layer. The coatings obtained with PEG showed higher photocatalytic activities than those obtained without PEG due to smaller size and higher dispersion of anatase nanocrystals in the coatings.     

Discrimination of coatings on wooden materials using the gas sensor system

The applicability of sensor system for the discrimination of sources of indoor pollution was investigated. As examples of indoor pollution sources, paint and lacquer coatings were considered. Commercially available preparations: Akrylux, Doamlux, Bejca and White Scandinavian were selected for headspace measurements using TGS sensor array. Following issues were investigated: (1) discrimination between water- and solvent-based coatings, (2) discrimination between one component coatings, and (3) discrimination between one component and two component coatings. Following data analysis methods were used: principal component analysis (PCA), linear discriminant analysis (LDA) and probabilistic neural network (PNN). Results showed that coatings could be discriminated successfully, provided the surface covered was solid wood (0-1.8% error). The interference of fibreboard volatiles in sensor measurements of coatings was most likely encountered. It could have significantly impaired discrimination of coatings on fibreboard (2.8-5.6% error) as compared to wood. Worst results were obtained for the discrimination of coatings on unknown material(12.5-28.7% error).     

Significantly enhanced photocatalytic activity of TiO2/TiC coatings under visible light

Journal of Solid State Electrochemistry - Rutile TiO2 forms on TiC coatings (TiO2/TiC coatings) during carbon-embedding heat treatment (cHT) for TiC coatings. The photocatalytic activity of...     

SiO2纳米粒子对溶胶凝胶涂层性能的影响

在高强钢表面制备了防护性溶胶凝胶涂层,并研究了不同浓度二氧化硅纳米粒子的加入对于涂层形貌、耐蚀性和硬度的影响。采用扫描电子显微镜(SEM)和电子能谱(EDS)观察了涂层的微观结构和成分;采用显微硬度计测试了涂层的硬度;采用电化学方法研究了二氧化硅纳米粒子的浓度对于涂层耐蚀性能的影响;采用傅里叶红外光谱研究涂层的化学结构,进而探讨了二氧化硅纳米粒子对于涂层的强化机理。结果显示涂层加入二氧化硅纳米粒子的最佳浓度为500 mg.L-1,此条件下的涂层表面均匀致密,有较高的硬度并且在3.5%NaCl溶液中体现出较好的耐蚀作用。纳米粒子在溶胶中反应形成活性羟基基团并与硅烷发生反应生成空间网状结构,从而强化涂层。     

Mechanical and tribological properties of DLC coatings deposited by plasma-based ion implantation and deposition method on polyoxymethylene

Polyoxymethylene (POM, polyacetal) is one of the most popular plastics for machine elements, especially in Japan. However, it is difficult to use it under severe operating conditions such as high speed and high contact pressure. Diamond-like carbon (DLC) coatings were well known to be tribological and functional coatings. However, both POM and DLC coatings are difficult to adhere them each other. In the present paper, DLC coatings are deposited by plasma-based ion implantation and deposition (PBIID) method on POM substrate, and validity of DLC coatings on POM was investigated through friction and mechanical tests. When gas pressure was 0.2 and 0.8 Pa, hardness and adhesion properties of DLC coating deposited under gas pressure of 0.5 Pa were lower compared with under 0.2 and 0.8 Pa. For preparing DLC coatings having hard and good adhesion properties, relatively thin substrate was suitable. A correlation between relative humidity in the laboratory and friction coefficient was confirmed while DLC coatings remain on the substrate.     

Fouling-release coatings prepared from alpha,omega-dihydroxypoly(dimethylsiloxane) cross-linked with (heptadecafluoro-1,1,2,2-tetrahydrodecyl)triethoxysilane

Surface properties of pristine and water-aged polymeric films made of alpha,omega-dihydroxypoly(dimethylsiloxane) (PDMS) cross-linked with (heptadecafluoro-1,1,2,2-tetrahydrodecyl)triethoxysilane (FTEOS17) or tetraethoxysilane (TEOS) were investigated. The FTEOS17-cured coatings showed stable advancing and receding contact angles over a period of 3 months of water exposure, compared to a 70 degrees decrease in receding contact angle for the TEOS-cured coatings. After immersion in water, hydroxyl groups were detected on the TEOS-cured coatings with attenuated total reflection infrared spectroscopy (ATR-FT/IR). Tapping-mode atomic force microscopy (TM-AFM) on pristine FTEOS17-cured coatings showed surfaces topologies ranging from smooth and featureless to topologically complex, depending on FTEOS17 concentration. The fluorinated coatings showed a stable surface morphology after water immersion, which we believe is due to the formation of a fluorinated siliceous phase that prevented the surface reconstruction, water penetration, and hydrolysis. The smooth pristine TEOS-cured coatings showed an increased roughness with cracks and erosion pits present on the surface after water immersion.     

Combinatorial and high-throughput screening of the effect of siloxane composition on the surface properties of crosslinked siloxane-polyurethane coatings

Libraries of siloxane-polyurethane coatings were designed, formulated, and screened using high-throughput experimentation. Four independent variables that were analyzed were the molecular weight of poly(dimethylsiloxane) (PDMS), presence or absence of poly(epsilon-caprolactone) (PCL) blocks attached to the PDMS backbone, the length of the PCL blocks, and the siloxane polymer level in the coating formulations. In addition to the siloxane libraries (3-aminopropyl-terminated PDMS and poly(epsilon-caprolactone)-poly(dimethylsiloxane)-poly(epsilon-caprolactone) (PCL-PDMS-PCL) triblock copolymers), the coating formulation included a trifunctional isocyanate crosslinker, trifunctional poly(epsilon-caprolactone) polyol, 2,4-pentanedione (pot-life extender), dibutyltin diacetate (catalyst), and a blend of solvents. The resulting coatings were analyzed for their surface energy and pseudobarnacle adhesion both before and after aging the coatings for 30 days in water. The water and methylene iodide contact angle averages increase with increasing molecular weight of PDMS. Coatings prepared from PCL-PDMS-PCL triblock copolymers have lower surface energies than coatings prepared from 3-aminopropyl-terminated PDMS; however, lower pseudobarnacle adhesion results were obtained for the coatings prepared from 3-aminopropyl-terminated PDMS than coatings prepared from PCL-PDMS-PCL triblock copolymers. The siloxane polymer level in the coating formulations does not have a significant effect on the surface energy of the coatings, but it resulted in higher pseudobarnacle adhesion.     

Electrochemical corrosion resistance performance of sustainable resource-based nanoconducting polymer composites in alkaline medium

The corrosion resistance performance of poly (otoluidine) (POT)-dispersed castor oil-polyurethane, (COPU) nanocomposite coatings, POT/COPU, with three different compositions (i.e. 0.25, 0.5 and 1.0 wt%) in alkaline medium is studied. The coatings are applied on mild steel specimens by brushing. Corrosion resistance behaviour of these coatings is investigated using potentiodynamic polarization measurements, electrochemical impedance spectroscopy (EIS) and by weight loss. The morphological behaviour of corroded and uncorroded coated specimens is investigated by scanning electron microscopy (SEM). It is interesting to report that the presence of conducting polymer nanoparticles in POT/COPU coatings suppresses the saponification of COPU in an alkaline environment. These investigations show that the dispersion of POT in COPU remarkably improves the corrosion resistance performance of COPU in alkaline media. POT/COPU (1.0 wt%) coatings have potential as anticorrosive-coating materials in alkaline media at higher pH. These coatings have a higher resistance to alkaline medium in comparison to other compositions.     

Polysilazane as the source of silica: the formation of dense silica coatings at room temperature and the new route to organic–inorganic hybrids

Xylene solutions of perhydropolysilazane (PHPS) were used as the coating solutions for preparing silica coatings at room temperature. The PHPS-to-silica conversion was achieved by exposing the spin-on coatings to the vapor from aqueous ammonia. In order to examine the significance of the mechanical properties of the PHPS-derived silica coatings, the pencil hardness was measured, which was compared with that of tetraethoxysilane (TEOS)-derived silica coatings. The pencil hardness was over 9H at a load of 1 kg, which was much higher than that of the TEOS-derived silica gel films, and was comparable to that of the TEOS-derived films heat treated at 300 °C. Second, poly(methyl methacrylate) (PMMA)–silica hybrid coatings were prepared from xylene solutions of PMMA and PHPS via exposure to the vapor from aqueous ammonia. Crack-free, optically transparent PMMA–silica hybrid coatings could be prepared, where PHPS-to-silica conversion was confirmed by infrared absorption spectroscopy. The refractive index was around 1.42–1.50, and the contact angle with water increased from 35 to 70° with increasing PMMA content. The pencil hardness greatly increased during the PHPS-to-silica conversion, and was much higher than that of the non-heat treated TEOS-derived hybrid coatings. The durability in tetrahydrofuran (THF) was also evaluated by measuring the reduction in thickness occurring during soaking in THF. The durability decreased with increasing PMMA content, but was much higher than that of the non-heat treated TEOS-derived hybrid coatings. Both the hardness and the durability were comparable to those of the TEOS-derived coatings heated at 300 °C. The hybrid coatings could also be deposited on poly(ethylene terephthalate) substrates, where no cracks were observed at high PMMA contents even when the substrate was bent.     

Electrosynthesis and analytical characterization of PMMA coatings on titanium substrates as barriers against ion release

The performance of polyacrylic coatings as barrier films against corrosion of titanium-based orthopaedic implants was investigated. In particular, poly(methyl methacrylate) (PMMA) was electrosynthesized on titanium substrates by electro-reductive processes from aqueous monomer solutions. The obtained PMMA coatings were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The effect of an annealing treatment on the morphology of coatings with respect to uniformity and porosity of films was assessed by scanning electron microscopy (SEM). An inductively coupled plasma-mass spectrometry (ICP-MS) technique was used for ion concentration measurements in ion release tests performed on TiAlV sheets modified with PMMA coatings (annealed and unannealed). Results indicated that the annealing process produces coatings with considerable anticorrosion performances.Electronic Supplementary Material Supplementary material is available for this article at     

Influence of Material Properties on the Damage-Reporting and Self-Healing Performance of a Mechanically Active Dynamic Network Polymer in Coating Applications

We conducted a detailed investigation of the influence of the material properties of dynamic polymer network coatings on their self-healing and damage-reporting performance. A series of reversible polyacrylate urethane networks containing the damage-reporting diarylbibenzofuranone unit were synthesized, and their material properties (e.g., indentation modulus, hardness modulus, and glass-transition temperature) were measured conducting nanoindentation and differential scanning calorimetry experiments. The damage-reporting and self-healing performances of the dynamic polymer network coatings exhibited opposite tendencies with respect to the material properties of the polymer network coatings. Soft polymer network coatings with low glass-transition temperature (~10 °C) and indentation hardness (20 MPa) exhibited better self-healing performance (almost 100%) but two times worse damage-reporting properties than hard polymer network coatings with high glass-transition temperature (35~50 °C) and indentation hardness (150~200 MPa). These features of the dynamic polymer network coatings are unique; they are not observed in elastomers, films, and hydrogels, whereby the polymer networks are bound to the substrate surface. Evidence indicates that controlling the polymer’s physical properties is a key factor in designing high-performance self-healing and damage-reporting polymer coatings based on mechanophores.     

Growth feature of PTFE coatings on rubber substrate by low‐energy electron beam dispersion

Polytetrafluoroethylene (PTFE) coatings were prepared on Si and acrylonitrile‐butadiene rubber substrates by low‐energy electron beam dispersion. The effects of substrate nature, distance of target to substrate (d_ts) and coatings thickness on the surface morphology, structure, and tribological properties of the coatings were investigated. The results showed that substrate nature affects the shape and size distribution of surface conglomerations of PTFE coatings due to the interaction process of active dispersion particles with underlying polymer layer. Surface energy of PTFE coatings decreases first with the coatings thickness increases to 1.25 µm and then slowly increases with the thickness. Structure defects (pore, interstice, and so on) in the coatings increase with the thickness increases but reduce significantly with the d_ts increases. PTFE coating prepared at the d_ts of 20 cm had a higher intensity of the amorphous absorption bands. Friction experiment indicated that the destroyed area of the coatings in the friction region decreases with increases the coatings thickness but increases with the d_ts. The rubber modified by PTFE coatings with spherical structure possesses a higher stability in the friction process and a lower coefficient of friction. Copyright © 2015 John Wiley & Sons, Ltd.     

Electrochemical corrosion behavior of nanocrystalline zinc coatings in 3.5% NaCl solutions

The corrosion behavior of electrodeposited nanocrystalline (NC) zinc coatings with an average grain size of 43 nm was investigated in 3.5% NaCl solutions in comparison with conventional polycrystalline (PC) zinc coatings by using electrochemical measurement and surface analysis techniques. Both polarization curve and electrochemical impedance spectroscopy (EIS) results indicate that NC and PC coatings are in active state at the corrosion potentials, and NC coatings have much higher corrosion resistance than PC ones. The corrosion products on both coating surfaces are mainly composed of ZnO and Zn₅(OH)₈Cl₂·H₂O, but the corrosion products can form a relatively more protective layer on NC coating surfaces than on PC coatings. The EIS characteristics and corrosion processes of PC and NC zinc coatings during 330 h of immersion were discussed in detail.     

Effects of sodium laurylsulfate on crystal structure of calcite formed from mixed solutions

This paper presents a solvent-based, mild method to prepare superhydrophobic, carbon nanofiber/PTFE-filled polymer composite coatings with high electrical conductivity and reports the first data on the effectiveness of such coatings as electromagnetic interference (EMI) shielding materials. The coatings are fabricated by spraying dispersions of carbon nanofibers and sub-micron PTFE particles in a polymer blend solution of poly(vinyledene fluoride) and poly(methyl methacrylate) on cellulosic substrates. Upon drying, coatings display static water contact angles as high as 158° (superhydrophobic) and droplet roll-off angles of 10° indicating self-cleaning ability along with high electrical conductivities (up to 309 S/m). 100 μm-thick coatings are characterized in terms of their EMI shielding effectiveness in the X-band (8.2-12.4 GHz). Results show up to 25 dB of shielding effectiveness, which changed little with frequency at a fixed composition, thus indicating the potential of these coatings for EMI shielding applications and other technologies requiring both extreme liquid repellency and high electrical conductivity.     

表层沉积物(生物膜)非残渣态组分的选择性萃取分离及其吸附铜/锌的特性

采用化学萃取技术对表层沉积物(生物膜)的非残渣态组分(铁、锰氧化物及有机质)进行了分离, 并研究了表层沉积物(生物膜)非残渣态和残渣态组分吸附铜、锌的特性. 结果表明, 0.1 mol/L NH2OH·HCl+0.1 mol/L HNO3, (NH4)2C2O4-H2C2O4缓冲溶液和体积分数为30%的H2O2可选择性地萃取分离表层沉积物(生物膜)非残渣态的锰氧化物、铁锰氧化物和有机质, 萃取率为63.15%～97.59%, 同时对非目的组分影响较小; 表层沉积物(生物膜)及其各组分对铜的吸附能力均大于对锌的吸附能力, 且生物膜及其各组分对铜、锌的吸附能力均高于表层沉积物及其相应组分对铜、锌的吸附能力; 表层沉积物(生物膜)非残渣态组分对铜、锌的吸附能力均大于残渣态组分, 且非残渣态组分中锰氧化物的单位吸附能力最强, 其次是铁氧化物, 而有机质的单位吸附能力较弱, 比锰氧化物低2个数量级, 说明生物膜对水体中痕量重金属的迁移转化作用强于表层沉积物, 而表层沉积物(生物膜)中金属(铁、锰)氧化物对水中痕量重金属起主要控制作用.     

PREPARATION AND PROPERTIES OF THERMOSETTING ACRYLIC COATINGS USING TITANIUM-OXO-CLUSTER AS A CURING AGENT

Thermosetting acrylic coatings were prepared by using carboxyl acid group-containing acrylic oligomer and curing with titanium-oxo-clusters which were first pre-hydrolyzed from titanium n-butoxide.The curing ability of the titanium-oxo-cluster was examined using a microdielectric analytical(DEA)curing monitor,Fourier transformed infrared spectroscopy(FTIR),and Soxhlet extraction experiments,and the properties of the resulted coatings were investigated with pendulum hardness tester,dynamic mechanical anal...     

Silver Chloride Loaded Hollow Mesoporous Silica Particles and Their Application in the Antibacterial Coatings on Denture Base

Hollow mesoporous silica particles(HMSPs) were prepared by using polystyrene microspheres as a template and loaded with silver chloride(AgCl) to act as antibacterial agents. The HMSPs possess radially oriented pore channels and a high loading amount of AgCl. The AgCl loaded HMSPs were then dispersed in hybrid coatings with different mass ratios to fabricate antibacterial coatings. The antibacterial activities of the coatings were tested against Candida albicans(ATCC 10231) and Streptococcus mutants(ATCC 25175). The resulting antibacterial coatings exhibited high antibacterial activities, high hardness, and acceptable adhesion to the substrate.     

Protein separations using polyelectrolyte multilayer coatings with molecular micelles in open tubular capillary electrochromatography

Novel polyelectrolyte multilayer (PEM) coatings for enhanced protein separations in open tubular CEC (OT-CEC) are reported. Use of four cationic polymers (poly-L-lysine, poly-L-ornithine, poly-L-lysine-serine, and poly-L-glutamic acid-lysine), and three anionic molecular micelles, sodium poly(N-undecanoyl-L-leucyl-alaninate) (poly-L-SULA), sodium poly(N-undecanoyl-L-leucyl-valinate) (poly-L-SULV), and sodium poly(undecylenic sulfate) (poly-SUS) were investigated in PEM coatings for protein separations. The simultaneous effects of cationic polymer concentration, number of bilayers, temperature, applied voltage, and pH of the BGE on the separation of four basic proteins (alpha-chymotrypsinogen A, lysozyme, ribonuclease A, and cytochrome c) were analyzed using a Box Behnken experimental design. The influence of NaCl on the run-to-run reproducibility was investigated for PEM coatings containing each cationic polymer. All coatings exhibited excellent reproducibilities with a %RSD of the EOF less than 1% in the presence of NaCl. Optimal conditions were dependent on both the cationic and anionic polymers used in the PEM coatings. Poly-L-glutamic acid-lysine produced the highest resolution and longest migration time. The use of molecular micelles to form PEM coatings resulted in better separations than single cationic coatings. Chiral poly-L-SULA and poly-L-SULV resulted in higher protein resolutions as compared to the achiral, poly-SUS. Furthermore, the use of poly-L-SULV reversed the elution order of lysozyme and cytochrome c when compared to poly-L-SULA and poly-SUS.     

Ambient-curable polysiloxane coatings: structure and mechanical properties

Ambient-curable polysiloxane coatings were prepared by hydrolysis and condensation of 3-methacryloxypropylmethyldimethoxysilane (MPDS) and methyltriethoxysilane (MTES) and subsequently mixing with 3-aminopropyltriethoxysilane (APS). The structures of the as-obtained polysiloxane oligomers as well as the dried polysiloxane coatings on tinplate substrates were analyzed by FTIR and ²⁹Si NMR. The mechanical properties of the coatings were thoroughly examined at both macro-level and micro-level using a pendulum hardness rocker, an impact tester, and a nanoindentation/nanoscratch instrument. Effects of the molar ratio of MPDS/MTES, the dosage of aqueous ammonia solution, and the catalytic condition on the structure of polysiloxane oligomers as well as the structure and mechanical properties of the polysiloxane coatings were investigated. The dried coatings with thickness of 15–26 μm are highly elastic. The hardness (Koenig hardness and microhardness), impact resistance and scratch resistance are mainly dependent on the condensation degree of polysiloxane coatings rather than on the organic component of the coatings. A proper pre-hydrolysis process or more APS is benefit for enhancing the mechanical strength of the polysiloxane coatings. Polysiloxane coatings with high hardness and excellent scratch resistance can be prepared preferentially at low molar ratio of MPDS/MTES.