Search results for "Contact angle"
showing 10 items of 138 documents
Artificial neural network based particle size prediction of polymeric nanoparticles.
2017
Particle size of nanoparticles and the respective polydispersity are key factors influencing their biopharmaceutical behavior in a large variety of therapeutic applications. Predicting these attributes would skip many preliminary studies usually required to optimize formulations. The aim was to build a mathematical model capable of predicting the particle size of polymeric nanoparticles produced by a pharmaceutical polymer of choice. Polymer properties controlling the particle size were identified as molecular weight, hydrophobicity and surface activity, and were quantified by measuring polymer viscosity, contact angle and interfacial tension, respectively. A model was built using artificia…
Double Step Electrochemical Process for the Deposition of Superhydrophobic Coatings for Enhanced Corrosion Resistance
2021
Superhydrophobic surface on anodized AA5083 sample was obtained by an electrochemical process. Scanning Electron Microscopy and Fourier Transform Infrared Spectroscopy analyses revealed the hierarchical structure of the coating and the presence of manganese stearate. These features were crucial for the coating superhydrophobicity, demonstrated by a measured contact angle of ~ 163° and its self-cleaning ability. Electrochemical characterization in an aqueous solution mimicking seawater proved an enhanced corrosion resistance due to the superhydrophobic coating with respect to anodized AA5083 sample that also lasted after 20 immersion days in Cl- containing electrolyte.
Determining efficacy of monitoring devices on ceramic bond to resin composite
2012
Objectives: This paper aims to assess the effectiveness of 3D nanoroughness and 2D microroughness evaluations, by their correlation with contact angle measurements and shear bond strength test, in order to evaluate the effect of two different acids conditioning on the bonding efficacy of a leucite-based glass-ceramic to a composite resin. Study Design: Ceramic (IPS Empress) blocks were treated as follows: 1) no treatment, 2) 37% phosphoric acid (H3PO4), 15 s, 3) 9% hydrofluoric acid (HF), 5 min. Micro- and nano-roughness were assessed with a profilometer and by means of an atomic force microscopy (AFM). Water contact angle (CA) measurements were determined to assess wettability of the ceram…
Do the contact angle and line tension of surface-attached droplets depend on the radius of curvature?
2018
Results from Monte Carlo simulations of wall-attached droplets in the three-dimensional Ising lattice gas model and in a symmetric binary Lennard-Jones fluid, confined by antisymmetric walls, are analyzed, with the aim to estimate the dependence of the contact angle $(\Theta)$ on the droplet radius $(R)$ of curvature. Sphere-cap shape of the wall-attached droplets is assumed throughout. An approach, based purely on "thermodynamic" observables, e.g., chemical potential, excess density due to the droplet, etc., is used, to avoid ambiguities in the decision which particles belong (or do not belong, respectively) to the droplet. It is found that the results are compatible with a variation $[\Th…
Entrapment of charged, nonwetting colloids near oil-water interfaces.
2007
Charged, nonwetting colloids with a contact angle $\ensuremath{\theta}=180\ifmmode^\circ\else\textdegree\fi{}$ are attracted to an oil-water interface due to image charge forces. Near the interface, the attractive image charge forces are balanced by repulsive van der Waals forces, and thus the colloids are trapped at a finite distance from the interface. Electrostatic and van der Waals pressure lead to a deformation of the interface in the equilibrium state. For parameters relevant to experiment, however, the effects of the deformed interface are negligible and thus the mutual interactions of such interfacially trapped colloids should be well characterized by electrostatic dipole repulsions.
Graphene and graphene oxide on Ir(111) are transparent to wetting but not to icing
2021
Anti-icing coatings reduce the freezing onset temperature for water by changing the chemical and physical environment at the water-substrate interface to prevent ice nucleation and growth. Graphene oxide has several attributes that make it attractive as an anti-icing coating and it has been theoretically predicted that graphene oxide has a lower freezing onset temperature than pristine graphene. Here, we test this hypothesis using carefully prepared, well-characterized graphene oxide substrates. We compare the water contact angle for graphene and graphene oxide coatings, both prepared on iridium(111) surfaces. The results show both materials to be transparent to wetting, but indicate a lowe…
Improved hydrophobicity of inorganic–organic hybrid mesoporous silica with cage-like pores
2013
International audience; Hydrophobic ordered mesoporous silica particles with cage-like pores (SBA-1 type) were prepared through co-condensation of phenyltriethoxysilane (PhTES) and tetraethylorthosilicate (TEOS) at different TEOS/PhTES molar ratios. It is shown that the hydrophobic character of the particles is enhanced by increasing the phenyl loading (decreasing the TEOS/PhTES molar ratio) and that it could be further enhanced by subsequent trimethylsilyl (TMS) grafting on remaining silanol groups (TMS-PhSBA-1 sample). This increase of hydrophobicity has been evidenced on the internal surface (mesoporosity) of the particles using water adsorption and, on the external surface of the partic…
PANI-Based Wearable Electrochemical Sensor for pH Sweat Monitoring
2021
Nowadays, we are assisting in the exceptional growth in research relating to the development of wearable devices for sweat analysis. Sweat is a biofluid that contains useful health information and allows a non-invasive, continuous and comfortable collection. For this reason, it is an excellent biofluid for the detection of different analytes. In this work, electrochemical sensors based on polyaniline thin films deposited on the flexible substrate polyethylene terephthalate coated with indium tin oxide were studied. Polyaniline thin films were abstained by the potentiostatic deposition technique, applying a potential of +2 V vs. SCE for 90 s. To improve the sensor performance, the electronic…
Morphological and Chemical Evolution of Gradually Deposited Diamond-Like Carbon Films on Polyethylene Terephthalate: From Subplantation Processes to …
2016
Diamond-like carbon (DLC) films on polyethylene terephthalate (PET) are nowadays intensively studied composites due to their excellent gas barrier properties and biocompatibility. Despite their applicative features being highly explored, the interface properties and structural film evolution of DLC coatings on PET during deposition processes are still sparsely investigated. In this study two different types of DLC films were gradually deposited on PET by radio frequency plasma-enhanced chemical vapor deposition (RF-PECVD) using acetylene plasma. The surface morphology of the deposited samples has been analyzed by atomic force microscopy (AFM). Their chemical composition was investigated by …
Polycaprolactone/gelatin-based scaffolds with tailored performance: in vitro and in vivo validation
2019
Abstract Nanofibrous scaffolds composed of polycaprolactone (PCL) and gelatin (Ge) were obtained through a hydrolytic assisted electrospinning process. The PCL-to-Ge proportion (100/0 to 20/80), as well as the dissolution time (24, 48, 72, 96, 120 h) into a 1:1 formic/acetic acid solvent before electrospinning were modified to obtain the different samples. A strong influence of these factors on the physicochemical properties of the scaffolds was observed. Higher Ge percentage reduced crystallinity, allowed a uniform morphology and increased water contact angle. The increase in the dissolution time considerably reduced the molar mass and, subsequently, fibre diameter and crystallinity were a…