Effect of Bio-Based Surfactant on Wettability of Low-Rank Coal Surface and Its Mechanism

In this study, the effect of a bio-based environment-friendly surfactant, cardanol polyoxyethylene ether (BGF), on the wettability of the surface of low-rank coal (LRC) and its mechanism were studied. The adsorption experiment showed that the adsorption of the surfactant conformed to the Langmuir adsorption model and the pseudo-second-order kinetic model. The adsorption was mainly affected by hydrogen bonding, and the adsorption rate was affected by intraparticle diffusion and liquid film diffusion. The wettability experiment showed that the influence of BGF on the wettability of the surface of LRC followed the given order: BGF-7 > BGF-10 > BGF-15. The investigation of adhesion work showed that the adhesion work and the stability of the coal–water system decreased after adsorption. Fourier transform infrared and X-ray photoelectron spectroscopy analyses showed that after adsorption, the peak strength of vinyl ether, the content of elemental carbon, and the content of C-C/C-H groups increased.

Surfaces with Adjustable Features—Effective and Durable Materials for Water Desalination

Materials based on PVDF with desirable and controllable features were successfully developed. The chemistry and roughness were adjusted to produce membranes with improved transport and separation properties. Membranes were activated using the novel piranha approach to generate OH-rich surfaces, and finally furnished with epoxy and long-alkyl moieties via stable covalent attachment. The comprehensive materials characterization provided a broad spectrum of data, including morphology, textural, thermal properties, and wettability features. The defined materials were tested in the air-gap membrane distillation process for desalination, and improvement compared with pristine PVDF was observed. An outstanding behavior was found for the PVDF sample equipped with long-alkyl chains. The generated membrane showed an enhancement in the transport of 58–62% compared to pristine. A relatively high contact angle of 148° was achieved with a 560 nm roughness, producing a highly hydrophobic material. On the other hand, it was possible to tone the hydrophobicity and significantly reduce adhesion work. All materials were highly stable during the long-lasting separation process and were characterized by excellent effectiveness in water desalination.

CALCULATION OF THE SURFACE PROPERTIES OF MICROELECTRONICS MATERIALS USING THE MODEL OF COORDINATION MELTING OF A CRYSTAL

In this work, it is shown that the model of coordination crystal melting makes it possible to calculate the values of the specific surface energy of elementary substances and the surface melting temperature of metals, and also relates the anisotropy of the specific surface energy of a crystal with its crystal structure, electron work function, and adhesion work.

INFLUENCE OF PECTIN AND CHITOSAN ON THE PROPERTIES OF GELS PROTECTING THE OESOPHAGEAL MUCOSA

Among the diseases of the digestive tract, gastro-oesophageal reflux is one of the most troublesome ailments. It is estimated that in highly developed countries, reflux symptoms occur in about 5%-10% of people every day. It has also been found that about 20% of people experience such symptoms once a week. The incidence of this disease increases with age, regardless of gender. The aim of the study was to investigate the physicochemical properties of gels intended for the protection of the oesophageal mucosa. Preparations containing 3.0% pectin showed the lowest pH. These gels can be used in the treatment of advanced alkaline reflux. The addition of chitosan to all tested gels increased their pH and dynamic viscosity. The texture tests showed the effect of pectin concentration on the adhesion work of the tested gels.

Optimization of titanium dioxide wetting in alkyd paint and varnish materials in the presence of surfactants

This paper reports the results of studying the influence of surfactants (SAS) on the wetting of titanium dioxide in alkyd paint and varnish materials (PVM), based on pentaphthalic (PPh) and alkyd-urethane (AU) film-forming substances. Edge wetting angle (θ°) and adhesion work (Wa) were used as the criteria for assessing the wettability of titanium dioxide. Three additives were used as SAS: the original product AS-1, obtained from waste of oil refining (with low cost), and industrial additives: "Telaz" and polyethylene polyamine (PEPA). All the studied additives in PPh and AU PVM improve the wetting of titanium dioxide. At the 30 % content of AS film-forming substance in the composition, the maximum decrease in θ° for AS-1 is 4.5°, for PEPA and Telaz it is 4°. For pentaphthalic composition under similar conditions, a decrease in edge wetting angle for AS-1 is 10 °, for Telaz 8.6°, and for PEPA 5.9°. According to the relative change in edge wetting angle for both systems, the maximum decrease in θ° is about 10 %. The introduction of SAS into the composition of AU ambiguously affects the adhesion work, for PPh, the introduction of SAS causes a decrease in adhesion work (Wa). AS-1 is the SAS that minimally reduces adhesion work. The compositions of the PVM by the method of probabilistic-deterministic planning, which ensures maximum wetting of titanium dioxide with film-forming solutions, were analyzed. The equations for calculating the edge angle of wetting of titanium dioxide depending on the content of solvent and the SAS in the PVM were derived. The effectiveness of the AS-1 product as a wetting additive for alkyd paints and varnishes was proven. The wetting ability of the original SAS – AS-1 is close to industrial additives PEPA and Telaz.

Study on the Adhesion Performance of Asphalt-Calcium Silicate Hydrate Gel Interface in Semi-Flexible Pavement Materials Based on Molecular Dynamics

The interface between an asphalt binder and a calcium silicate hydrate (C-S-H) gel is a weak point of semi-flexible pavement material. In this study, the adhesion performance of asphalt-C-S-H gel interface in semi-flexible pavements at a molecular scale has been investigated. Molecular dynamics (MD) simulations were applied to establish three asphalt binders: 70# asphalt binder (the penetration is 70 mm), PG76-22 modified asphalt binder (a kind of asphalt binder that can adapt to the highest temperature of 76 °C and the lowest temperature of −22 °C), and S-HV asphalt binder (super high viscosity). The effects of different temperatures and SBS modifier contents on interfacial adhesion were explored. The obtained results showed that temperature variations had little effect on the adhesion work of the asphalt-C-S-H gel interface. It was also found that by increasing the content of SBS modifier, the adhesion work of the asphalt-C-S-H gel interface was increased. The molecular weight of each component was found to be an important factor affecting its molecular diffusion rate. The addition of SBS modifier could regulate the adsorption of aromatics by C-S-H gel in the four components of asphalt binder and improve the adsorption of resins by C-S-H gel.

First Principle Study of TiB2 (0001)/γ-Fe (111) Interfacial Strength and Heterogeneous Nucleation

TiB2/316L stainless steel composites were prepared by selective laser melting (SLM), and the adhesion work, interface energy and electronic structure of TiB2/γ-Fe interface in TiB2/316L stainless steel composites were investigated to explore the heterogeneous nucleation potential of γ-Fe grains on TiB2 particles using first principles. Six interface models composed of three different stacking positions and two different terminations were established. The B-terminated-top 2 site interface (“B-top 2”) was the most stable because of the largest adhesion work, smallest interfacial distances, and smallest interfacial energy. The difference charge density and partial density of states indicated that a large number of strong Fe-B covalent bonds were formed near the “B-top 2” interface, which increased the stability of interface. Fracture analysis revealed that the bonding strength of the “B-top 2” interface was higher than that of the Fe matrix, and it was difficult to fracture at the interface. The interface energy at the Ti-poor position in the “B-top 2” interface model was smaller than that of the γ-Fe/Fe melt, indicating that TiB2 had strong heterogeneous nucleation potency for γ-Fe.