High Adhesion Research Articles

Additive Manufacturing of Watertight ABS Parts and Its Use for Chemical Metal Plating

AbstractOne of the most frequently used polymers in the galvanic industry as well as for Fused Filament Fabrication (FFF) is the terpolymer of acrylonitrile butadiene styrene (ABS). Its surface is etched in chromosulfuric acid to enable the chemical deposition of a metal. The use of chromium (Cr)(VI) compounds is restricted in the European Union (EU) since 2017. A new plating process is proposed here that does not rely on etching. Instead, double bonds on the ABS surface are converted to epoxides, followed by grafting of a polyethylenimine (PEI) to the surface. The so modified plastic is an ideal starting point for metal plating. Printing often leads to the formation of voids between strands and layers, which hinders subsequent wet processing. The plating process introduced here requires high demands on the water tightness of parts. The proposed printing procedure reduces the degree of penetration of water from 50% to less than 0.1% at 2 bar water pressure. The combination of the new printing procedure with the new plating process results in the deposition of industrial relevant nickel (Ni) layers. The cross‐hatch test followed by a peel test exhibits values of zero, pointing to the high adhesion of Ni to ABS.

Lactobacillus helveticus LZ-R-5 Ameliorates DSS-Induced Colitis in Mice by Modulating Gut Microbiota and Enhancing Intestinal Barrier Function.

Lactobacillus helveticus LZ-R-5 (R-5), a strain with high epithelial adhesion and bioactive exopolysaccharide production, was isolated from Tibetan kefir grains. This study investigated its potential to alleviate intestinal inflammation using a DSS-induced colitis model in BALB/c mice. We integrated microbial diversity and serological analyses to assess changes in gut flora and cytokines following the R-5 treatment. Pathological assessments showed that R-5 reduced crypt distortion in the proximal colon and mitigated hepatic immune challenges by enhancing gut barrier function. The increased relative expression of TGF-β1 and the downregulation of NLRP3-related inflammatory factors were conducive to preventing organ damage in the thymus and spleen of mice with colitis. Additionally, R-5 stimulated GPR43 expression and improved epithelial nutrition, promoting mucin production to prevent enterotoxin leakage. It also modulated the gut microbiota by suppressing Bacteroides and Erysipelatoclostridium, leading to a microbiota composition more akin to that of normal flora.

High-Performance Triple-Network Hydrogels Derived from Chrome Leather Scraps: Ultrahigh Compressive Strength, Adhesion, and Self-Recovery.

The development of engineered hydrogels with high strength, self-recovery, and adhesion is essential for applications requiring resistance to large deformations and cyclic loading. Herein, a triple-network (TN) hydrogel with ultrahigh compressive strength, strong adhesion, and good self-recovery was constructed by using tannic acid-modified chrome leather scrap hydrolysate as the first network, polyacrylamide as the second network, and poly-2-propenamide-2-methylpropanesulfonic acid as the third network. The ultrahigh (70 MPa compressive strength and 95% compression deformation) TN hydrogels were effectively created, which is attributed to the synergy of the three networks. The TN hydrogels display adhesion (adhesion strength > 20 kPa) ascribed to the introduction of phenolic hydroxyl groups in tannic acid. Intriguingly, the TN hydrogels exhibit excellent self-recovery performance (93.6% dissipated energy recovery at 70 °C) and shape memory performance (restored to the original shape in 20 s). These properties are essential for the development of high-performance hydrogels and promote the resource utilization of leather waste.

Expanding the Applications of Copper-based Alloys by Thermal Arc Spraying

In this article, the case of depositing a Ni-based alloy layer by thermal arc spraying on a copper alloy substrate with cylindrical geometry over its entire surface is presented. After the coating was deposited, the layer was analyzed microstructurally both on the surface and in cross-section, and it was observed that it adhered very well to the substrate. In addition to the high adhesion to the substrate, a low porosity of the coating was observed, which ensures good compactness of the coating. Based on these results, further investigation of the Ni coating can be recommended to limit the toxicity caused by the oxidation of copper and copper alloy heating elements.

Bioactive glass suspension hydrogel promotes wound healing by modulating fibroblasts

The irritation and adhesion of wound healing biomaterials to wet wounds should be addressed for achieving effective wound healing. In this study, a stable multifunctional hydrogels (BGs/HA suspension gels) were prepared using superfine powder of bioactive glasses (BGs), the biocompatible materials hyaluronic acid (HA) and carbomer940, which had good adhesion and low irritation properties for use in moist complex wounds. The average particle size of BGs/HA suspension gels was 13.11 ± 0.29μm, and the BG content was 15.8 ± 0.2% (m m-1). The results of cell proliferation, cell migration, and immunofluorescence staining experiments showed that in the initial stage of wound healing, the ionic extract of BGs formulations promoted the proliferation and migration of L929 cells and induced the secretion ofα-SMA and collagen I. In the final stage of repair, the ionic extract of the BGs formulation regulated the differentiation of fibroblast, which contributed to the reduction of pathological scar formation.In vivoexperiments showed that the wound healing rate of BGs/HA suspension gels group exceeded higher than that of the conventional BGs superfine powder group. Although BGs/HA suspension gels were comparable to its commercially available counterpart (Dermlin paste) in promoting wound healing, it addressed the problem of localized irritation caused by the high pH and low adhesion of BGs products. This study confirmed the specific regulatory effect of BGs/HA suspension gels on L929 cells, which provided a reference for the clinical application of BGs in wound dressing.

Preparation and Corrosion Resistance of Superhydrophobic Composite Coatings on Shot-Peened AA 7075-T6 Aluminum Alloy

In order to further improve the corrosion resistance of 7075-T6 aluminum alloy after shot peening, corrosion-resistant superhydrophobic coatings (EP-HDTMS@SiO2) containing epoxy resin (EP), cetyltrimethoxysilane (HDTMS), and nano-silica (SiO2) were prepared by a simple spraying method on the surface of shot-peened AA 7075-T6 aluminum alloy. The effects of different EP/SiO2 mass ratios on the micro-morphology, surface wettability, and corrosion resistance of the superhydrophobic composite coatings were analyzed. Due to the combination of microstructure and the modification of low surface energy organics, the contact angle of EP-HDTMS@SiO2 coatings reached the superhydrophobic level (152.6°). The electrochemical tests showed that the corrosion current densities (Icorr) of the EP-HDTMS@SiO2 composite coatings were both significantly lower than those of the EP-HDTMS coatings and matrix aluminum alloys. The addition of SiO2 nanoparticles could improve the hydrophobicity and corrosion resistance of epoxy-based composite coatings. Due to the increase in surface roughness and epoxy resin, the shot-peened AA 7075-T6 alloy coating had high adhesion after the peel test. The prepared coatings also showed excellent corrosion resistance in the neutral salt spray test. This study provides a simple method for preparing stable superhydrophobic coatings on metal surfaces, which is expected to expand the application of 7075 aluminum alloy in harsh environments.

Isolation, evolution, and biological characterization of non-virulent and non-drug-resistant Escherichia coli from porcine intestine.

Previous studies have predominantly focused on the pathogenic mechanisms and epidemiological investigations of pathogenic Escherichia coli (E. coli), but much remains unknown about the non-virulent and non-drug-resistant E. coli (NVNR E. coli) residing in the pig gut. In this study, 215 E. coli strains were identified from fecal samples collected from 26 healthy pigs in Guangdong Province, China. Among them, 12 NVNR E. coli strains were identified through PCR, antibiotic susceptibility tests, and genomic virulence analysis. Phylogenetic analysis revealed that 8 of these NVNR E. coli strains were located in the upstream cluster of the phylogenetic tree, which we consider as the ancestral phylogroup of porcine native E. coli. Notably, strain 2-9 showed a close evolutionary relationship with the probiotics Nissle1917 and EcAZ-1, suggesting it may also be a probiotic strain. These 9 strains (i.e., the 8 ancestral phylogroup strains and the suspected probiotic strain) were designated as evolutionarily superior strains. The 12 NVNR E. coli strains were non-hemolytic and exhibited growth rates comparable to typical E. coli strains, but they varied significantly in their tolerance to gastrointestinal conditions and adherence to IPEC-J2 cells. Most of them lacked the ability to inhibit pathogenic E. coli. Interestingly, the majority of strains exhibiting strong gastrointestinal tolerance, most of those with high adhesion capacity, and all strains possessing antibacterial ability, were found within the range of 9 evolutionarily superior strains. These findings suggest that 9 strains have shown great potential as superior porcine native E. coli strains and warrant further study.

Bioinspired interfacial engineering of multiscale micro/nano-structured surfaces with robust superhydrophobic and tunable adhesion

Creating superhydrophobic surfaces with varying liquid–solid adhesion holds significant applications in waterproofing, lab-on-chip, and self-cleaning. Biological superwetting surfaces, such as lotus leaf and rose petal, leverage hierarchical micro/nanoscale surface structures together with low-surface-energy chemicals, to synergistically tune their adhesion. However, existing synthetic technologies encounter great difficulty in constructing sophisticated micro/nano architectures for robust, adhesive superhydrophobic surfaces, especially on fabrics. Here, we present a bioinspired interfacial engineering methodology of “artificial papillae + glue” which allows the construction of tunable multiscale micro/nano structures for superhydrophobic fabrics with mechanical robustness (mechanical friction up to 100 cycles) and varying adhesion (69.4–216.5 µN). For our methodology, artificial papillae with tunable 3D topological architectures, fluorinated alky chains, and hydrosilylation-reactive C = C groups, are designed and synthesized as the robust anchoring groups to different concentrations of polydimethylsioxane (PDMS) glue and applied to hydrophilic substrates. The PDMS-dominated surfaces form microwrinkles with high adhesion, ideal for microdroplet manipulation and hemostasis, meanwhile artificial papillae-dominated surfaces offer low adhesion and excellent self-cleaning properties. This biomimetic “artificial papillae + glue” strategy enables the creation of tunable multi-scale micro/nanostructures for robust adhesive antiwetting interfaces, offering promising applications in droplet manipulation, hemostasis, and beyond.

Influence of hydrogen bonding interactions, entanglement, and covalent crosslinking on the viscoelasticity of acrylic viscoelastomers containing urea group

The structure–property relationship of acrylic clear viscoelastomer films (acrylic CVFs) as foldable optical clear adhesives (OCAs) has always been unclear. In our work, a series of acrylic CVFs with different hydrogen-bonding interactions (H-bondings) and cross-linking densities (namely, CL-H-copolymers) were synthesized. The effects of entanglement, H-bonding, and covalent crosslinking on the recovery and adhesive properties of CL-H copolymers were analyzed by rheology, equilibrium swelling, and tensile stress–strain tests (tensile tests). The structural parameter Mx/MeH was obtained by combining the affine deformation model, the Flory-Rehner equation, and the UCM-Gent model, where Mx is the molecular weight between covalent crosslinkers and MeH is the a physical crosslinking molecular weight affected by H-bondings. The experimental results showed that the CL-H-copolymers had an obvious dependence on Mx/MeH. Recovery properties tended to stabilize (>90 %) at Mx/MeH < 1, while adhesion strengths continued to decrease with decreasing Mx/MeH. This conclusion and methodology are instructive for the design of foldable OCAs with high elasticity and high adhesion performance.

End-to-End Pierced Carbon Nanosheets with Meso-Holes.

The remarkable properties of 2D nanomaterials are well known. However, their high interfacial adhesion energy often leads to restacking issues, limiting their potential in various applications. A strategic synthetic approach is presented to overcome this challenge. Specifically, the study first demonstrates the use of layered aluminosilicate as a sacrificial 2D template to allow the growth of highly ordered meso-holey polymeric layers, which can be subsequently exfoliated upon the removal of aluminosilicate and thermally converted to perpendicularly open meso-holey carbon (POMC). On the other hand, perpendicularly blocked meso-holey carbon (PBMC) is obtained with non-sacrificial 2D template of graphene oxide. When both POMC and PBMC are evaluated by operando hydrodynamic electrochemical impedance spectroscopy and transmission line model analysis for electrochemical reduction of oxygen, POMC achieves a remarkable improvement of charge transfer and mass transfer by up to 4.1 and 7.9 times, respectively, as compared to PBMC. This study therefore highlights the importance of perpendicularly open 2D nanoarchitectures in circumventing the restacking effect, offering valuable insights for leveraging 2D nanomaterials with open meso-holes in various applications.

Homologous-adhering/targeting cell membrane- and cell-mediated delivery systems: a cancer-catch-cancer strategy in cancer therapy

Abstract Low tumor enrichment remains a serious and urgent problem for drug delivery in cancer therapy. Accurate targeting to tumor site is still a critical aim in cancer therapy. Though there have been a variety of delivery strategies to improve the tumor targeting and enrichment, biological barriers still cause most delivered guests to fail or be excreted before they work. Recently, cell membrane-based systems attract a huge amount of attention due to their advantages such as easy access, good biocompatibility and immune escape, which contribute to their biomimetic structures and specific surface proteins. Furthermore, cancer cell-based delivery systems are referred to homologous-targeting function in which they exhibit significantly high adhesion and internalization to homologous-type tumor sites or cells even though the exactly mechanism is not entirely revealed. Here, we summarize the sources and characterizations of cancer cell membrane systems, including reconstructed single or hybrid membrane-based nano/micro carriers, as well as engineered cancer cells. Additionally, advanced applications of these cancer cell membrane systems in cancer therapy are categorized and summarized according to the components of membranes. The potential factors related to homologous targeting of cancer cell membrane-based systems are also discussed. By discussing the applications, challenges, and opportunities, we expect the cancer cell membrane-based homologous-targeting systems have a far-reaching development in preclinic or clinics.

High-performance S cathode through a decoupled ion-transport mechanism

A high-performance sulfur (S) cathode is essential for advanced lithium-sulfur (LiS) batteries. Issues such as shuttle effect of polysulfides and low conductivity of S need to be resolved. Here, we report a S-cathode prepared via constructing unique decoupled ion-transport network formed from soy protein-based ionic conductor with well-dispersed graphene, leading to mitigated shuttle effect and excellent dual-conductive capabilities, i.e., high electronic and ionic conductivities. The decoupled ion-transport mechanism, which is unconventional in polymeric systems, is enabled by appropriately maintaining the denatured soy protein structure during the cathode preparation, facilitating polysulfide trapping and providing high adhesion for the S cathode, confirmed by the experiment and simulation results. Consequently, the LiS battery with the protein-based S cathode demonstrates excellent rate performance and long cycling stability. In specific, the LiS battery with the protein-based S cathode shows ∼70 % capacity retention (∼504 mAh g−1) after 600 cycles under the current density of 0.5 A g−1. This work will initiate new scientific studies on introducing an unconventional ion-transport mechanism into electrodes for producing high-performance batteries.

Control system and process optimization for electroless nickel plating

A novel method based on mid-frequency vibration is proposed to eliminate coating defects such as bubbles during electroless nickel plating. An automated control system for the plating, enabling precise and stable measurements and adjustments of critical parameters such as plating solution temperature, pH, and nickel ion concentration, is also established, which significantly improves process efficiency and coating quality. Experimental results indicate that the system is capable of realizing stable operation over extended periods. A nonporous nickel–phosphorus coating with a thickness greater than 200 μm is successfully obtained, with high phosphorus content, robust adhesion, and superior machinability.

Magnetically responsive superhydrophobic surface: Reversible switching for water repellency and active/passive anti-icing

This research aims to address the negative impact of global climate change on equipment stability, with a particular focus on the occurrence of icing on working surfaces at low temperature. To this end, we have developed a novel magnetically responsive superhydrophobic surface to enhance anti-icing properties and adapt to environmental changes. We prepared magnetically responsive micro-cilia arrays (MRMAs) with good flexibility and magnetostriction through a facile spray gun coating technique. By adjusting the application mode and distance of the magnetic field, three different morphologies can be achieved: vertical, curved and crossed, thus optimizing water repellency, active anti-icing and passive anti-icing performance. Experimental data show that vertical MRMAs exhibit extremely high contact angles and low droplet adhesion, which facilitates rapid water droplet removal, while curved MRMAs exhibit the lowest ice adhesion strength, which effectively reduces the likelihood of ice formation. In addition, the crossed MRMAs excelled in delaying icing, significantly prolonging the time before water droplets begin to freeze. This research not only provides a novel anti-icing strategy, but also offers new ideas for designing multifunctional surfaces that can adapt to complex environmental conditions.

Effect of polyphenol-hydrocolloids interaction on protein oxidation, structure and water distribution properties of thermally processed meat

In order to overcome the weakness and instability of polyphenols during thermal processing, the effect of various food additives including hydrocolloids combined with Gallic acids (GA) on structure, water distribution and oxidative properties of roasted meat was investigated. The findings publicized that the combined addition of GA with carrageenan (CAR) and sodium pyrophosphate (SPP) significantly (P < 0.05) decreased cooking loss, surface hydrophobicity, carbonyl formation and prevented the loss of sulfhydryl groups compared to alone GA and control. The fluorescence spectroscopy and FT-IR analysis showed that combination of GA with CAR and/or SPP decreased hydrophobic aggregation, prevented oxidation of side chain amino acids residues and developed GA-CAR/SPP non-fluorescent complexes with proteins. The inhibitory mechanism of G-CAR and G-SPP was predominated by retaining tightly bound water inside the macromolecules and prevented its seepage from the myofibrillar fiber network, which was also evidenced by high adhesiveness and gumminess of those samples. The microstructure endorsed the compact structure of those samples whereas uneven surface and intercellular spaces were noticed in control samples. Finally, correlation and principal component analysis further differentiated the most influential parameters and mechanism of action. These findings suggest that GA alone is not compatible for thermal processing until supported by an effective additive having potential of creating synergism to improve the thermal stability and quality characteristics of meat.

Anatase‐reinforced PtZn@Silicalite‐1 structured catalysts boosting propane dehydrogenation

AbstractStructured catalysts exhibit the advantages of high diffusion efficiency and low heat transfer resistance, which have attracted increasing attention to non‐adiabatic gas–solid process. However, the metal‐supported coating catalysts face the problems of weaker bond strength and severe sintering, especially under the conditions of large flow rate and high temperature. Herein, metal@Silicalite‐1 structured catalysts with high adhesion and thermal stability were successfully prepared by hydroxylating the substrate with anatase. Rich surface Ti‐OH significantly strengthened the adhesion stability of the zeolite coating. In propane dehydrogenation reaction, the optimized PtZn@S‐1‐15Ti showed a high specific activity of 49.6 molC3H6·molPt−1·s−1 with propylene selectivity above 99% at 600°C. The introduction of anatase accelerated the aggregation of silicon sources and induced nucleation with growth content of zeolite increased by 3.6 times. It breaks the inherent contradiction between high loading amount and strong binding ability of coated catalysts, which broadens the avenues for industrial applications.

Impact resistance and high-speed dry cutting performance against titanium alloy of AlCrBON coatings with various oxygen contents

In this work, four AlCrBON coatings with various oxygen contents were fabricated. As the oxygen content increased, a phase transition from fcc-(Cr, Al)N to fcc-(Cr, Al)(O, N) occurred, the Al-O and Cr-O bonds increased while Al-N and Cr-N bonds reduced. The AlCrBON coating with a 13.4-atom% oxygen content (C2 coating) exhibited a high nano-hardness (39.6 GPa) and scratch adhesion (with Lc2 of more than 70 N), low high-frequency impact force (0.7 N), less delamination, and more cutting times (10 min under 80 m/min and 240 s under 100 m/min) against titanium alloy under both cutting speeds. Addition of O relieved the wear both on the flank face and rake face of the coated inserts against titanium alloy throughout the cutting process.

A novel bonding strategy of hydrogel on titanium alloy for marine antifouling engineering: Multiple antifouling mechanisms and DFT calculations

Marine biofouling is one of the biggest problems for titanium alloys and rutile TiO2 coatings in marine engineering applications. Hydrogel materials are a novel and environmentally benign antifouling strategy, but they cannot be stabilized on alloy surfaces to provide long-term protection. Focusing on the challenges of bonding at the hydrogel-alloy interface, a PAA/PHEMA composite hydrogel containing Cu2O@PEG powder was strongly bonded to the titanium alloy by forming chemical bonds with APTES. The composite hydrogel still achieves an adhesion strength of 60–70 kPa after 7 days of immersion. The samples maintained a stable copper ion leaching rate of 2.61–3.76 μg·cm−2·d−1 after 21 days of immersion. The coating-modified titanium alloys showed a 100 % bactericidal rate within three hours of contact with different bacteria and exhibited a high anti-algal adhesion rate of up to 99 %. In addition, the attachment mode of APTES on rutile TiO2 was clarified for the first time by Density Functional Theory (DFT) calculations. According to DFT calculations, the adsorption energy of APTES on Ti-TiO2 is −747.025 kJ/mol, and the adsorption energy of acrylic acid on TiO2-APTES is −535.152 kJ/mol. The chemical bonding connection between the hydrogel-alloy interface, as a novel interface bonding strategy, would be expected to broaden the application of titanium alloy in marine engineering.

Superhydrophobicity With Self-Adaptive Water Pressure Resistance and Adhesion of Pistia Stratiotes Leaf.

Superhydrophobic surfaces are promising for optimizing amphibious aircraft by minimizing water drag and adhesion. Achieving this involves ensuring these surfaces can resist high liquid pressure caused by deep water and fluid flow. Maximizing the solid-liquid contact area is a common strategy to improve liquid pressure resistance. However, this approach inevitably increases solid-liquid adhesion, making it challenging to guarantee a trade-off between the two wetting characteristics. Here, it is found that the Pistia stratiotes leaf exhibits superhydrophobicity with high water pressure resistance and low adhesion, attributed to its self-adaptive deformable microstructure with unique re-entrant features. Under pressure, these microstructures deform to increase the solid-liquid contact area, thereby enhancing water pressure resistance. The re-entrant features elevate the deformation threshold, enabling higher modulus microstructures to achieve adaptive response. This facilitates the recovery of deformed microstructures, restoring the air layer and maintaining low adhesion. Following these concepts, Pistia stratiotes leaf-inspired surfaces are fabricated, achieving an 183% improvement in water impact resistance and an ≈80% reduction in adhesion after overpressure compared to conventional superhydrophobic surfaces. The design principles inspired by Pistia stratiotes promise significant advancements in amphibious aircraft and other trans-media vehicles.

Stainless Steel Deposits on an Aluminum Support Used in the Construction of Packaging and Food Transport Containers

A series of chemical elements from the chemical composition of the packs of liquid food products migrate inside them or they combine with other chemical elements existing in the food, resulting in chemical compounds that worsen the quality of the food. In the present paper, layers of food stainless steel were deposited using thermal arc spraying on an aluminum alloy substrate to stop the migration of aluminum ions inside liquid food products. The physical-chemical and mechanical properties of the protection system: stainless steel layer used in the food industry (suggestively called: food-grade stainless steel)—aluminum substrate were investigated, and then the organoleptic properties of the food liquids that came into contact with the deposit were evaluated. It was found that food-gradestainless steel deposits have low porosity (3.8%) and relatively high adhesion and hardness, which allows complete isolation of the substrate material. The investigations carried out on the properties of food liquids that come into contact with the stainless steel deposit revealed the fact that it perfectly seals the aluminum start. The food-grade stainless steel coating (80T) was much better and safer for preserving dairy products maintaining a constant acidity up to 17 degrees Thorner, wines (with an average acidity of 3.5–4 degrees), juices (with natural pigments), and oils (with a good absorbance level correlated with clarity). This aspect suggests that the created system can be successfully used to manufacture containers for the transport of liquid products.