Gloss evaluation and prediction of achromatic low‐gloss textured surfaces from the automotive industry

In this article, we investigate the benefit of including texture information in models of gloss perception of low‐gloss textured achromatic plastic surfaces from the automotive industry. 4 models are compared: two gloss prediction models including texture information, one using data from reflectometry (M1) and one using data from goniophotometry (M2), and two models using data from reflectometry (M3) or goniophotometry (M4) alone. Both texture‐corrected models (M1‐M2) outclass the uncorrected intensity‐based models, mainly because they are made texture invariant. Although the texture‐corrected reflectometer‐based prediction (M1) correlates rather well with sensory data, a more consistent fit is obtained by mixing textural to goniophotometric data (M2). This can be explained by the fact that contrast gloss is better than multiangle specular gloss at reflecting the observer's gloss evaluation strategy. © 2015 Wiley Periodicals, Inc. Col Res Appl, 41, 154–164, 2016     

Checking gloss factors on glassy surfaces

Translated from Steklo i Keramika, No. 4, pp. 16–17, April, 1989.     

Slippery lubricant-infused textured aluminum surfaces

To overcome instability of the lotus-inspired surfaces, slippery lubricant-infused surfaces inspired by Nepenthes pitcher plant were fabricated by the combination of fluorinated hierarchical texture and perfluoropolyether (PFPE). The hierarchical structures composed of facets, cavities, and nanoflakes were formed on the aluminum substrates by the HCl etching and the boiling water treatment. After surface fluorination, PFPE can spread over the textured aluminum surfaces via capillary effect to form continuous and homogeneous liquid films. The liquid repellency of the textured surface was demonstrated by visible experimental results and contact angle measurements. Due to the hierarchical structures that trapped enough lubricant and resisted the deformation of lubricant film, the lubricant-infused textured aluminum surface exhibited an excellent liquid repellency, low sliding angles for various liquids, and high environmental durability. Therefore, this slippery aluminum surface would be a good candidate for liquid-repellent surfaces to meet emerging needs in practical applications.     

Control over wettability of textured surfaces by electrospray deposition

Microtextured surfaces were prepared by electrospray deposition (ESD) from hydrophilic and hydrophobic acrylic resin solutions. The surface morphologies and topologies were characterized using scanning electron microscopy and laser profile microscopy, respectively. Wetting behaviors on the surfaces were characterized by contact angle and sliding angle measurements. The contact angle of the water droplet on the hydrophilic resin‐coated surfaces decreased with an increase in the surface roughness. On the other hand, the contact angle on the hydrophobic resin‐coated surfaces increased with an increase in the surface roughness. In addition, a patterned surface composed of aligned fibers by ESD showed anisotropy of both wetting and sliding behaviors. These results indicate that ESD is a useful method for designing a textured surfaces and controlling the surface wettability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3811–3817, 2007     

Intelligent polymeric surfaces through molecular self-assembly

Recently, stimuli-responsive surfaces have gained considerable interest among coatings researchers in industry as well as in academe. To date, many switchable surfaces based on such external stimuli as temperature, electricity, pH, and many others have been designed and developed. Environmentally switchable surfaces have been among the most widely studied surfaces since they are known to exhibit smart behavior under external influence. In the present work, we report the synthesis of hydrophobic, hydrophilic, and amphiphilic polyurethane coatings with tethered hydrophilic and/or hydrophobic moieties. These coatings have been characterized and tested for mechanical properties and surface characteristics using such advanced instruments as the scanning probe microscope (SPM), dynamic contact angle analyzer (DCA), adhesion tester, and nanoindenter. The surfaces with tethered hydrophobic or hydrophilic moieties, when immersed in water, showed remarkable changes in the surface topography, hence, their dynamic surface characteristics. The amphiphilic surfaces, containing both hydrophobic and hydrophilic moieties, showed intelligent behavior in response to the external environment. The ability to tailor surfaces with predictable behavior upon exposure to the external environment opens up enormous opportunities for their potential end-use applications. This paper was presented at the FSCT FutureCoat! 2007 Conference, Toronto, Canada, October 3–5, 2007, and was selected as the “best student paper” for the A.L. Hendry Award.     

Self-assembled microstructured polymeric and ceramic surfaces

Self-assembled microstructures were manufactured by dip coating of substrates with unfilled and filler-loaded preceramic polymer mixtures in the presence of a solvent and a non-solvent. The nature of the polymers was characterized by their solubility parameters. Variation of the polymer/polymer ratio and the volume fraction of the solvent and/or non-solvent led to different surface structures. Studies of the structure formation mechanism indicate that demixing processes of the polymers are responsible for self-assembly in filler-free mixtures. In filler-loaded mixtures the structure formation process, however, is more complex. The micro-structured polymeric coatings obtained from filler loaded systems were converted into polymer derived ceramic coatings under shape retention. High specific surface areas were measured after thermal conversion.     

Wettability control of laser textured SiC surfaces using additive elements

Wettability control of laser textured SiC ceramic surfaces through the addition of pure elements was studied in this work. A correlation analysis between the elements C/O/Si/B/Al/Fe and the contact angle demonstrates that elements C/O/Si/B are all highly correlated with the wettability. The correlation of elements Fe/Al with the contact angle is relatively lower. Because elements C/Si are inherent elements in a SiC material, element O is derived from oxidation, and element B is added along with the additives during the sintering process. A more hydrophilic SiC surface was obtained by controlling the addition of element B.     

Advanced techniques for nanocharacterization of polymeric coating surfaces

Surface properties of a polymeric coating system have a strong influence on its performance and service life. However, the surface of a polymer coating may have different chemical, physical, and mechanical properties from the bulk. In order to monitor the coating property changes with environmental exposures from the early stages of degradation, nondestructive techniques with the ability to characterize surface properties with micro- to nanoscale spatial resolution are required. In this article, atomic force microscopy has been applied to study surface microstructure and morphological changes during degradation in polymer coatings. Additionally, the use of AFM with a controlled tip-sample environment to study nanochemical heterogeneity and the application of nanoindentation to characterize mechanical properties of coatings surfaces are demonstrated. The results obtained from these nanometer characterization techniques will provide a better understanding of the degradation mechanisms and a fundamental basis for predicting the service life of polymer coatings. Presented at the 81st Annual Meeting of the Federation of Societies for Coatings Technology on November 12–14, 2003, in Philadelphia, PA.     

Electrochemically etched pores and wires on smooth and textured GaAs surfaces

The electrochemical etching behaviors of GaAs on smooth and textured surfaces were systematically investigated in aqueous KOH electrolytes. When the applied potential was higher than the pore formation potential (PFP), the electrochemical etching of the smooth surface could be categorized into three regions: pore/wire formation, texturing, and electropolishing regions. Triangular GaAs nanowires were observed at low potentials while pronounced lateral etching occurred at high potentials. In the case of the textured surface, which consisted of groove arrays, more complicated etching behavior was demonstrated. The pore growth direction changed from 〈1 1 1〉B to 〈0 0 1〉 at a high current density while accompanying a drastic change in the pore morphologies such as tetrahedron-like pores along 〈1 1 1〉B transforming into 200 μm deep pores propagated along the 〈0 0 1〉 direction.     

Bioinspired steel surfaces with extreme wettability contrast

The exterior structures of natural organisms have continuously evolved by controlling wettability, such as the Namib Desert beetle, whose back has hydrophilic/hydrophobic contrast for water harvesting by mist condensation in dry desert environments, and some plant leaves that have hierarchical micro/nanostructures to collect or repel liquid water. In this work, we have provided a method for wettability contrast on alloy steels by both nano-flake or needle patterns and tuning of the surface energy. Steels were provided with hierarchical micro/nanostructures of Fe oxides by fluorination and by a subsequent catalytic reaction of fluorine ions on the steel surfaces in water. A hydrophobic material was deposited on the structured surfaces, rendering superhydrophobicity. Plasma oxidization induces the formation of superhydrophilic surfaces on selective regions surrounded by superhydrophobic surfaces. We show that wettability contrast surfaces align liquid water within patterned hydrophilic regions during the condensation process. Furthermore, this method could have a greater potential to align other liquids or living cells.     

Photoactive nanocoating for controlling microbial proliferation on polymeric surfaces

A novel antimicrobial polymeric surface coating involving photo-activated generation of the well-known microbiocidal agent hydrogen peroxide was investigated. Modified poly(ethylene imine) (PEI) polymers were prepared containing anthraquinone (AQ) moieties attached covalently to the amino functional groups of the PEI chains. These AQ-modified PEI polymers were applied from solution to the surface of corona-treated low-density polyethylene (LDPE) films. Photoreduction of the PEI-bound anthraquinone derivatives occurred on exposure to low energy UV light, resulting in efficient production of hydrogen peroxide from the coated film on exposure to air.     

Formation of coatings with tailored properties on polyperoxide-modified polymeric surfaces

Modification (peroxidation) of polymer surfaces, polypropylene, polyethylene, polyethylene terephthalate, nylon 6-6, poly(phenylene oxide), and ethylene–propylene copolymer were affected by the surface grafting of functional polyperoxides (FPPs) such as poly(5-tert-butylperoxy-5-methyl-1-hexene-3-yne-co-octylmethacrylate) (VEP-co-OMA), poly{N-[(tert-butylperoxy)-methyl]acrylamide-co-octyl methacrylate} (PO-co-OMA), and poly(tert-butylperoxy-methacrylate-co-octyl methacrylate) (PEst-co-OMA). The degree of surface modification was shown to be determined primarily by the structure of the polymer substrate. Using a peroxidized surface as an initiator of grafted copolymerization enabled the grafting of functional monomers (acrylic acid, acrylamide, 4-vinylpyridine, and hydroxyethyl methacrylate) and polysaccharides (heparin, dextran, etc.) and thereby imparted adhesive, antibacterial, haemocompatible properties to the polymer surface.     

Replication of laser‐textured alumina surfaces by polydimethylsiloxane: Improvement of surface hydrophobicity

Alumina tiles are textured by a laser beam to obtain improved hydrophobic characteristics at the surfaces. Since the textured surfaces are optically opaque, the resulting surfaces are copied and replicated by polydimethylsiloxane (PDMS). Some of the texture features such as whiskers‐like structures with complex shapes could not be copied by PDMS and synthesized silica particles are deposited onto PDMS copied and replicated surfaces to create a lotus effect. Analytical tools are incorporated to characterize the PDMS copied and replicated surfaces as well as synthesized silica particles deposited surfaces. Dynamic water contact angle measurements are carried out to assess hydrophobic characteristics of the resulting surfaces. It is found that PDMS copied and replicated surfaces have almost identical surface texture morphology to that of laser treated surface. Introducing synthesized silica particles improved the lotus effect on the PDMS copied and replicated surfaces; in which case, the hysteresis of droplet contact angle remains significantly low. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44015.     

Development and physicochemical characterization of modified polymeric surfaces for bacterial adhesion

Radiation‐induced graft polymerization was used to modify the surfaces of polypropylene (PP) sheets for bacterial adhesion. For the experiments, two monomers were mixed: the quaternary ammonium salt (QAS) [2‐(methacryloyloxy)ethyl]trimethylammonium chloride and acrylic acid (AAc). The PP sheets were activated by electron‐beam radiation before the grafting reaction. Different AAc/QAS comonomer mixture ratios (50 : 10, 40 : 20, 30 : 30, 20 : 40, and 10 : 50) were used to determine the degree of grafting and to make the PP surfaces hydrophilic. The graft level increased with an increase in the percentage of AAc in the comonomer mixtures. Synergism was investigated during graft polymerization to quantify the poly(acrylic acid) and poly{[2‐(methacryloyloxy)ethyl]trimethylammonium chloride} graft fractions in the resulting graft copolymers. An approximation of the graft fractions was made with an analytical technique based on acid–base volumetric titration. The wettability of the modified surfaces was determined by the measurement of the water contact angles. The surfaces prepared with higher percentages of QAS in the comonomer mixtures had lower contact angles than those prepared with lower percentages of QAS. The presence of oxygen and nitrogen on the modified PP surfaces was investigated with X‐ray photoelectron spectroscopy. Structural changes in unmodified and modified PP were characterized with differential scanning calorimetry. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

琉璃瓦用低温烧成结晶釉的试制

实验主要采用单因素实验法考察了不同助烧剂和烧成制度对结晶釉面的影响，在1180－1220℃下制备出了低温烧成的琉璃瓦用结晶釉。     

Speculations about the value of gloss

An hypothesis is presented claiming that gloss derives its commercial and aesthetic values from attracting attention. Gloss appears to mimic motion, which triggers strong responses that are deeply rooted in the biological heritage, shared by humans and animals. Conclusions are translated into a few simple rules for the design of surfaces.     

The effect of gloss on color

A model was developed for the effect of gloss on reflected color, taking the measurement geometry of the color measuring device into account. It considers the total front surface reflectance of a given sample to be independent of gloss and determined only by its refractive index and the angle of the incident beam. Although the total front surface reflectance is fixed, its specular component increases (and the diffuse component decreases) with increasing sample gloss. Therefore, the diffuse reflectance factor measured by a spectrophotometer decreases with sample gloss. In this article, a defined curve was fitted to the measured reflectance factor of black xerographic print samples having a range of gloss values for the 0/45 and diffuse spectrophotometer geometries, and this curve was used to predict the CIELAB color values for samples of the other colors at various gloss levels. The predicted color was compared to the measured color for cyan, magenta, yellow, red, green, and blue images that spanned a wide range of gloss. The RMS color error between the predicted and measured color of all of these images was found to be about 3 CIELAB ΔE* units. © 1999 John Wiley & Sons, Inc. Col Res Appl, 24, 369–376, 1999