Adhesion Strength Research Articles

Rigid-Flexible Coupled Dendritic Molecule Doping: General Approach to Activate Commercial Polymers into Harsh Condition-Tolerant Multi-Reusable Strong Supramolecular Adhesives.

Developing functional adhesives combining strong adhesion, good recyclability and diverse harsh-condition adaptability is a grand challenge. Here, we introduce a general dendritic molecule doping strategy to activate commercial polymers into a new family of supramolecular adhesives integrating high adhesion strength, ultralow temperature, water resistant and multi-reusable properties. Our method involves rational design of a new rigid-flexible coupled dendritic molecule-M4C8OH as a versatile dopant, while simple M4C8OH doping into commercial polymers can modulate internal and external non-covalent interaction to enable H-bonding enhanced interchain cross-linking for tough cohesion along with enhanced interphase interaction. This endows 20 wt % M4C8OH-doped polycaprolactone (PCL) adhesives (PCL-M4C8OH) with improved adhesion strength on various substrates with the maximum increase up to 2.87 times that of PCL. In particular, the adhesion strengths of PCL-M4C8OH on polymethyl methacrylate at 25 °C and -196 °C reach 4.67 and 3.58 MPa-1.9 and 2.3 times those of PCL and superior to diverse commercial adhesives and most reported adhesives. PCL-M4C8OH also displays markedly-improved multi-usability and tolerance against ultralow temperature and diverse wet environments. Mechanism studies reveal the crucial role of M4C8OH molecular structures toward superior adhesion. Our method can be expanded to other polymer matrices, yielding diverse new supramolecular adhesives.

Influence of Detonation Spraying Parameters on the Microstructure and Mechanical Properties of Hydroxyapatite Coatings.

The process of osteointegration depends significantly on the surface roughness, structure, chemical composition, and mechanical characteristics of the coating. In this regard, an important direction in the development of medical materials is the development of new techniques of surface modification and the creation of bioactive ceramic coatings. Calcium-phosphate materials based on hydroxyapatite have been proposed as bioactive ceramic coatings on titanium implants for the effective acceleration of bone tissue healing. To obtain bioactive ceramic coatings, pulse power sources are best suited, namely detonation spraying, in which the energy of the explosion of gas mixtures is used as a source of pulse action. The pulse mode of operation in the detonation spraying method is preferable for the formation of bioactive ceramic coatings. It provides a high velocity of hydroxyapatite particles, which promotes their effective fixation on the titanium substrate, while minimizing the heating of the material. This approach preserves the substrate structure and improves the coating adhesion. Four different types of coatings with varying O2/C2H2 molar ratios, ranging from 2.6 to 3.7, were obtained using detonation spraying. Powders and obtained coatings of hydroxyapatite were studied by Raman spectroscopy and XRD structural analysis. The results of XRD phase analysis showed the partial conversion of the hydroxyapatite phase to the α-tricalcium phosphate (α-TCP) phase during the detonation spraying process. The results obtained by Raman spectroscopy indicate that hydroxyapatite is the main phase in coatings. All hydroxyapatite-based coatings exhibited hydrophobic properties, which was confirmed by contact-angle values above 90° in wettability tests, characteristic of hydrophobic surfaces. The adhesive strength of the coatings was measured by the scratch test method. Tribological tests were conducted using the ball-on-disk method under both dry conditions and in Ringer's solution. This approach enabled the evaluation of wear resistance and friction coefficient of the coatings in different environments, simulating both lubrication-free conditions and those resembling physiological environments.

Novel rubber-steel adhesive based on resole phenol formaldehyde/unsaturated polyester/soybean oil polyol blends with high thermal stability performance

One of the main challenges in rubber-metal adhesive is improving the adhesion strength performance with high thermal stability. A novel rubber-steel adhesives based on resole phenol formaldehyde/unsaturated polyester/soybean oil polyol blends were fabricated to tackle this challenge. SEM investigated the morphology of the fabricated blends, while the curing reaction and the components’ interactions were evaluated using FT-IR and XRD. The heat resistance and curing properties were studied by TGA and DSC. The adhesion properties for rubber-metal adhesive specimens were tested at room temperature. The impact of soybean oil polyol modifier addition was investigated on adhesion performance. The curing conditions (touch dry, full curing, and shelf life) and hardness were investigated. It is obvious that polyol improves the heat resistance of the prepared films and enhances their adhesion behavior. The fabricated adhesive exhibits good adhesion and thermal stability due to the integration of chemical cross-linking in the matrix. It can adhere extensively to substrate surfaces via intermolecular forces with small physical movements. Controlling the curing time and delaying the shelf life could be possible for samples that take a long time to cure completely. The designed fabricated adhesive appeared to desired properties of satisfactory rubber-metal adhesion and good thermal stability.

Multifunctional laser-ablated lubricant-infused slippery film with self-sensing and anti-icing/deicing properties

In this paper, we have developed a multifunctional laser-ablated lubricant-infused slippery film (MLLSF) by combining laser-induced graphene and lubricant-infused processes. Due to its lubricant-infused slippery surface characteristics, the MLLSF can decrease the ice adhesion strength to 7 kPa and prolong the ice time to 5 min at -20 °C. At the same time, benefitting from the outstanding photothermal effect of the laser-induced graphene conductive network, the surface temperature can rapidly rise from -20 °C to 45.6 °C in 60 s under 808-NIL illumination, thereby effectively melting the ice. More importantly, owing to the temperature sensing ability of the LIG conductive network, the prepared MLLSF can monitor the whole process of droplet icing and deicing process in real time. Therefore, this MLLSF with self-sensing, anti-icing and deicing properties has important practical values in monitoring and removing ice.

Complex Coacervates: From Polyelectrolyte Solutions to Multifunctional Hydrogels for Bioinspired Crystallization

Hydrogels represent multifarious functional materials due to their diverse ranges of applicability and physicochemical properties. The complex coacervation of polyacrylate and calcium ions or polyamines with phosphates has been uncovered to be a fascinating approach to synthesizing of multifunctional physically crosslinked hydrogels. To obtain this wide range of properties, the synthesis pathway is of great importance. For this purpose, we investigated the entire mechanism of calcium/polyacrylate, as well as phosphate/polyamine coacervation, starting from early dynamic ion complexation by the polymers, through the determination of the phase boundary and droplet formation, up to the growth and formation of thermodynamically stable macroscopic coacervate hydrogels. By varying the synthesis procedure, injectable hydrogels, as well as plastic coacervates, are presented, which cover a viscosity range of three orders of magnitude. Furthermore, the high calcium content of the calcium/polyacrylate coacervate (~19 wt.%) enables the usage of those coacervates as an ions reservoir for the formation of amorphous and crystalline calcium-containing salts like calcium carbonates and calcium phosphates. The exceptional properties of the coacervates obtained here, such as thermodynamic stability, viscosity/plasticity, resistance to acids, and adhesive strength, combined with the straightforward synthesis and the character of an ions reservoir, open a promising field of bioinspired composite materials for osteology and dentistry.

Functional organic adlayers for controlling the adhesion strength of electrolessly deposited copper on super-engineering plastics

Effective metallization of super-engineering plastics such as liquid crystal polymers (LCP) and polyphenylene sulfides (PPS) via electroless deposition of copper thin films is an important step in the manufacturing of a wide range of devices. Copper deposition typically requires a pre-treatment step involving chemical and/or mechanical roughening to ensure high adhesion at the polymer/Cu interface; however such treatments are detrimental to patterns and topographic features of the polymer that possess µm resolution and/or high aspect ratio. Herein, we demonstrate that it is possible to regulate and improve adhesion of electrolessly deposited copper thin films at LCP and PPS materials via multilayer functionalization with aryldiazonium cations of a p-aminobenzoic acid precursor. We first demonstrate that aryldiazonium grafting conditions can be optimized to overcome the chemical inertness of LCP/PPS without resorting to harsh oxidative or mechanical treatments. We then show that the density of Ar-COOH groups can be regulated by modifying the number of functionalization cycles. X-ray photoelectron spectroscopy studies shows that this has a clear impact on the composition of the catalytic nanoparticle layer required for copper deposition. Adhesion strength studies demonstrate that such changes translate into improved adhesion strengths without any adverse effects on surface roughness. Control experiments with alternative chemical moieties suggest that specific chemical interactions between catalytic seeds and grafted carboxylate groups play an important role in the observed improved adhesion.

Laser Assisted Cold Spray of Aluminum Alloy 6061: Experimental Results

Laser-assisted cold spray (LACS) is investigated for its potential to improve the mechanical properties of cold spray deposits made by using nitrogen as the gas that carries the powder. High strength cold spray deposits are typically achieved by using the more expensive and resource limited helium. In this work, a laser collocated with the spray spot was used in nitrogen CS operations and the porosity, adhesion strength, tensile strength, and fatigue performance of aluminum alloy 6061 (Al6061) were examined. Using the laser improved all the performance metrics. By increasing the spray spot temperature from 180°C to 455°C, the porosity of the deposit reduced to 0.24% from 1.73%. The adhesion strength was increased from 18.4MPa to 76.6MPa. The tensile strength was increased from 34.3MPa to 167.6MPa, and the elongation was increased from 0.07% to 15.58%. It was shown that using laser heating during deposition increases the residual stress in the deposit, but its effects can be counteracted by using a hotplate beneath the substrate. Fatigue testing showed that fatigue performance was largely driven by tensile strength. These results are discussed in the context of in-situ temperature data and metallographic analysis. Analysis indicates these improvements are due to the combined effects of material softening, improved bonding between particles, and various heat treatment modalities.

Analysis of load-displacement curves of an adhesive-reinforced composite patch repaired plate using the combination of XFEM and CZM techniques

Since the development of the eXtended Finite Element Method (XFEM), Cohesive Zone Modelling (CZM), and the Virtual Crack Closure Technique (VCCT) for damage analysis in repaired structures, it has now become easy to validate experimental tensile tests carried out on damaged and repaired plates with a composite patch. In most cases, these tensile tests can be expensive and time-consuming due to surface preparation, cleaning, polishing, adhesive application, and the crosslinking time of the adhesive, which must be carefully considered. The analysis of damage in structures assembled by adhesive bonding is crucial to predicting their behavior under various loading conditions. Moreover, the analysis of experimental curves is in most cases translated a global behavior without taking into account the details that can influence the results. With the introduction of techniques (XFEM, CZM and VCCT), it is now possible to model different forms of damage, accounting for several mechanical and geometric parameters of the plate, patch, and adhesive. This work aims to analyze the behavior under tensile loading of a 2024-T3 aluminum plate presenting an initial crack of different lengths emanating from a central circular notch. This plate is repaired by a carbon/epoxy type patch through an adekit A140 adhesive. The combined use of XFEM to track damage in the plate and CZM for adhesive debonding allowed the acquisition of tensile load-elongation curves and the assessment of damage inflicted by loading on the plate. The results demonstrate that the combined use of XFEM and CZM techniques enables the identification of the adhesive debonding impact on the load transfer to the patch and consequently on the strength of the repaired structure. Furthermore, these highlight that the decrease in the effectiveness of the composite patch with increasing crack size is directly linked to the progressive deterioration of both the plate and the adhesive strength.

Rheological Properties and Modification Mechanism of Emulsified Asphalt Modified with Waterborne Epoxy/Polyurethan Composite.

In research aimed at improving the brittleness of WER (waterborne epoxy)-modified emulsified asphalt, commonly encountered issues are that the low-temperature performance of this type of asphalt becomes insufficient and the long curing time leads to low early strength. Matrix-emulsified asphalt was modified with WPU (waterborne polyurethane), WER, and DMP-30 (accelerator). Firstly, the performance changes of modified emulsified asphalt at different single-factor dosages were explored through conventional performance tests and assessments of its adhesion, tensile properties, and curing time. Secondly, based on a response surface methodology test design, the material composition of the composite-modified emulsified asphalt was optimized, and its rheological properties were analyzed by a DSR test and a force-ductility test. Finally, the modification mechanism was explored by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The results show that WER can improve the adhesion strength of modified emulsified asphalt and greatly reduce elongation at break. WPU can effectively improve the elongation at break of composite-modified emulsified asphalt, but it has a negative impact on adhesion strength. DMP-30 mainly affects the curing time of modified emulsified asphalt; EPD (composite modification) can effectively improve the high-temperature rutting resistance of matrix-emulsified asphalt, and its low-temperature performance is significantly improved compared with WER-modified emulsified asphalt. The EPD modification process mainly consists of physical blending. In the case of increasing the curing rate, it is recommended that the contents of WER and WPU be lower than 10% and 6%, respectively, to achieve excellent comprehensive performance of the composite modification.

An adaptive bionic sensor: enhancing ankle joint tracking with high sensitivity and superior cushioning performance

Flexible sensors are renowned for their rapid responsiveness, high flexibility, and outstanding mechanical properties, making them ideal for applications in wearable devices, sports and health monitoring, and human-machine interfaces. To enhance the sensing performance of these flexible sensors, researchers have drawn inspiration from nature, creating various bionic microstructures. However, these structures often manifest in the macroscopic form of thin films, which do little to improve impact resistance and joint protection. In response, this work achieves a highly sensitive and impact-resistant pressure sensor by integrating bionic principles at both micro and macro levels. Specifically, at the micro level, a muscle-like hydrogel system consisting of MXene nanosheets incorporated into the double network of polyvinyl alcohol and sodium alginate matrix is selected. At the macro level, the bionic prototypes of mimosa leaves and durian spikes with good energy absorption structure, together with octopus’ sucker with good adsorption capacity are selected, and the synergistic construction of the three structures is realized through 3D printing methods. The obtained sensor has an appropriate response range, sensitivity and stability. More importantly, the displacement deformation of the hydrogel can be reduced by 91.22%, while its adhesion strength can be increased by 57.5% compared to the unstructured hydrogel. As a proof-of-concept, the proposed bionic flexible sensor can be used to monitor the motion status of the human ankle joint in real-time, thereby assisting users in making real-time judgments on gait health.

Nitric acid-modified amorphous alloy fiber and its effects on mechanical properties of ultra-high performance concrete (UHPC)

The traditional steel fiber UHPC has the phenomenon of low strength and poor durability, which can not give full play to the practical value of UHPC. Nevertheless, amorphous alloy fibres possess notable strength, flexibility and corrosion resistance. The incorporation of amorphous alloy fibres into ultra-high performance concrete (UHPC) has been demonstrated to enhance the strength and toughness of UHPC. However, the surface of amorphous alloy fibres is characterised by a smooth and hydrophobic quality, which presents a challenge in terms of the interface bond with the cement matrix. In order to address this issue, three concentrations of nitric acid (HNO3, 2 mol/L, 4 mol/L and 6 mol/L) were employed to modify the surface of amorphous alloy fibres, and then the amorphous alloy fibres were incorporated into the cement matrix for fiber pull-out test, compression, flexural strength and impact testing. The changes in the physical and chemical properties of the amorphous alloy fibres before and after modification were analysed, and the effects on the interface bond strength and dynamic and static mechanical properties of UHPC were studied by means of SEM. The results demonstrate that the adhesion strength of the modified amorphous alloy fibre with 4 mol/L HNO3 is the most robust, with an increase of 18.7 % in compressive strength, 13.8 % in flexural strength, and 5.4 % in impact resistance. The method has been demonstrated to be effective in strengthening and toughening the cement matrix with HNO3-modified amorphous alloy fibres.

Fabrication and characterization of UV-curable thiol-functionalized siloxane elastomers with enhanced adhesion for flexible substrates

The rapid advancement of flexible and wearable devices has increased the demand for substrate materials with excellent elasticity, biocompatibility, and transparency. Polydimethylsiloxane (PDMS) is widely used in these applications due to its advantageous properties. However, its inherently low surface energy limits its adhesion in high-stretchability contexts. To address this issue, various surface modification techniques have been developed, but these methods often alter the intrinsic properties of PDMS or introduce complexities in the manufacturing process. This study proposes elastomers based on ultraviolet (UV)-curable siloxane resins, which retain outstanding flexibility and transparency while significantly enhancing adhesion properties. UV-curable siloxanes were synthesized to prepare elastomers that were evaluated for their mechanical, thermal, and surface properties in comparison with PDMS. Results indicate that the prepared elastomers can be rapidly cured under UV exposure, achieving storage moduli 6 and 37 times higher than those of PDMS at 25°C and 100°C, respectively. Furthermore, thermal conductivity improved by 60%, and the coefficient of thermal expansion was reduced by 26%, demonstrating superior mechanical stability across diverse conditions. Adhesion properties were also markedly enhanced, as shown by peel-test adhesion strength that was 7 times greater than that of conventional PDMS.

The Cr/Cr2N multilayer coating with high load-bearing capacity and thermal shock resistance

By utilizing the multi-arc ion plating (MAIP) technique, multilayer coatings with varying Cr/Cr2N ratios and uniform thicknesses were deposited onto a nitrided Cr–Ni–Mo–V steel substrate. The evolution of microstructure and mechanical properties was characterized using scanning electron microscopy, X-ray diffraction, and micro-Vickers hardness testing. The load-bearing capacity of the multilayer coatings with varying modulation ratios was comprehensively evaluated through Vickers indentation tests with a 10-kgf load, Rockwell hardness testing with a 150-kgf load, and scratch tests with loads of 60 and 100N. The coating with a Cr/Cr2N layer modulation ratio of 0.2/0.4 μm exhibited a hardness of 1385 HV and an adhesion strength of 91N. Under a 10kgf load, this coating also demonstrated excellent fracture toughness, and did not exhibit any radial cracks in the Vickers indentation. Subsequently, a thermal shock test, involving quenching from 900°C water to 25°C, was conducted on the coating with the best comprehensive performance. The multilayer coating with high load-bearing capacity could withstand 52 thermal shock cycles before delamination occurred. Failure analysis further confirmed that the multilayer coating with enhanced load-bearing capacity effectively resisted thermal shock.

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.

Multi-functional Gleditsia sinensis galactomannan-based hydrogel with highly stretchable, adhesive, and antibacterial properties as wound dressing for accelerating wound healing

Design and development of a multifunctional wound dressing with self-healing, adhesive, and antibacterial properties to attain optimal wound closure efficiency are highly desirable in clinical applications. Nevertheless, conventional hydrogels face significant barriers in their mechanical strength, adhesive performance, and antibacterial properties. Herein, a tough hydrogel based on aldehyde-grafted galactomannan was synthesized through radical copolymerization and Schiff base reaction, incorporating hyaluronic acid, acrylamide, and the zwitterionic monomer to create a multi-crosslinked structure. The multiple crosslink structure pattern consisting of multiple hydrogen bonding, ionic interactions, reversible Schiff bases bonds, and molecular chain entanglement endowed this hydrogel with multiple functionalities, including high tensile strength (25 kPa), tensile strain (2200 %), toughness (391.59 kJ/m3), and Young's modulus (9.77 kPa). The presence of catechol groups and zwitterionic groups endow hydrogels with outstanding adhesion strength (42.21 kPa), which satisfied the adhesive demand for the ample motion of specific areas. The zwitterionic monomer provided long-lasting antibacterial properties and promoted migration and growth of negatively charged cells, capable of establishing efficient antibacterial barriers and serving as wound dressing. The in vivo and vitro experiments manifested that the optimized hydrogel demonstrated an inconspicuous inflammatory response, facilitating rapid healing of full-thickness skin wound in rat models. Therefore, this work provides a promising strategy and an ideal candidate for wound healing dressings in treating infected skin wounds.

Functionalized porous 316 L stainless-steel with oil reservoir against ice adhesion

Slippery liquid-infused porous surfaces (SLIPSs) are used in anti-fouling, anti-icing and anti-corrosion, but lack of long-term durability is a challenge due to lubricant depletion. SLIPS with self-lubricating properties can achieve extended durability without reapplying the lubricant. Generally, lubricant is stored close to surface, thus lubricant reservoir is limited. Here bulk of porous material acts as lubricant reservoir in 316L stainless-steel SLIPS with self-lubricating properties for lowering ice adhesion. The reservoir was fabricated by using a space holder technique in metal injection molding (MIM) with lubricant reservoir volume up to 17.3%. Surface was activated with vinyltrimethoxysilane (VTMS) to attract lubricant. Ice adhesion strength was increased up to three times against non-porous reference in ice adhesion testing using porous surface without lubrication. The best performing SLIPS showed 6.7 times lower ice adhesion against counterpart porous surface without lubricant and 1.7 times lower than non-porous reference. This self-lubrication was achieved on mechanically durable structure having an adjustable lubricant storage capacity by temperature-driven phenomenon during de-icing.

Recyclable VOCs-free eutectic adhesive based on hydrogen bond fusion strategy with robust adhesion, flame retardancy, transparency, high durability, and low-temperature resistance

Although emerging supramolecular adhesives have addressed the challenge of traditional adhesives in terms of de-bonding through non-covalent interactions, they still face issues such as high synthetic difficulty, elevated costs, and inadequate adhesion strength, particularly under low temperatures. Additionally, achieving robust adhesion to low-energy hydrophobic surfaces remains a persistent challenge. This paper proposes a novel hydrogen bond fusion strategy to address these challenges, presenting the synthesis of a new HCX eutectogel, containing intramolecular fused hydrogen bonds and intermolecular hydrogen bonds. This approach enables the attainment of high-strength adhesion on both hydrophilic (up to 10.61 MPa) and hydrophobic (up to 4.87 MPa) substrates. Notably, the HCX eutectogel stands out for its ability to maintain stable adhesion performance at low temperatures (−80 °C & liquid nitrogen) and its extraordinary flame retardancy and recyclability. These findings contribute novel insights into the development of high-performance adhesives with multifunctionality, promising advancements in diverse applications.

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 2.61~3.76μg·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 -747.025kJ/mol, and the adsorption energy of acrylic acid on TiO2-APTES is -535.152kJ/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.

A high-strength, environmental-friendly, and multifunctional soy protein adhesive inspired by biomineralization

Soy protein is an economical and eco-friendly adhesive material that offers significant potential for the development of bio-based adhesives. However, they have poor water resistance, low bonding strength, mold-susceptibility, and deterioration, which are serious challenges to the widespread application of soy protein adhesives in plywood. This work was inspired by the biomineralization phenomenon and the preparation of a novel soy protein adhesive (SPI-RGT-AgNPs). The SPI-RGT-AgNPs adhesive exhibited excellent viscosity, residual rate, and moisture absorption performance compared with the original soy protein isolate (SPI) adhesive, with an increase from 37° (SPI) to 81° (SPI-10RGT-10AgNPs) in water contact angle testing. The dry and wet adhesion strengths reached 2.49MPa and 1.43MPa, 193% and 117% higher than SPI adhesive, respectively. Molecular docking simulations were used to verify that the introduction of modifiers significantly improved the stability and crosslinking strength of the adhesive. The best ratio of the SPI-RGT-AgNP adhesive was confirmed using the response surface methodology (RSM). Simultaneously, SPI-RGT-AgNPs adhesive also showed excellent anti-mildew and anti-microbial efficiencies to Escherichia coli (98.18%) and Staphylococcus aureus (99.33%). In addition, a life-cycle assessment was used to explore the pollution emissions from the adhesives. As compared to formaldehyde-based adhesives, the SPI-RGT-AgNP adhesive had lower energy consumption and pollution emissions. Therefore, this study prepared a novel high-strength and multifunctional soy protein adhesive, guiding the production of multifunctional and green adhesives.

Electrophoretic deposition of novel antibacterial and biocompatible polydopamine and ZIF-8 hybrid composite coating on anodized Ti-6Al-4V alloy with silane primary substrate

Production of biocompatible and corrosion resistance dental implant is a requirement in the modern dental science. In this work, the Ti-6Al-4V was used alloy for the dental implant application that has investigated to make it more corrosion resistive and antibacterial with electrophoretic deposition of silane precursor solution that made of acidic solution of tetraethyl orthosilicate (TEOS) and methyl three ethoxy silane (MTES). The optimized silane coating has been achieved with 30 V, 30 min and at 100 °C ramped annealing by comparison of Taffel analysis and electrochemical impedance spectroscopy (EIS). Also, a new nanocomposite including polydopamine (PDA) and zeolite imidazole frame work composed from Zn (NO3)2 .6H2O and 2-methylimidazole (ZIF-8) that name PDA@ZIF-8 has been used as biocompatible and corrosion resistance amplifier to the precursor solution and used in the multilayer deposition process. The morphology analysis including atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM) imaging and the obtained parameters show that coating has appropriate roughness that could increase the bounding of implant. A good adhesion strength has been determined for the two-layers silane coating with PDA@ZIF-8 according to the pull- off test. On the other hand, the antibacterial analysis indicate that the coating is an effective material for S. mutans and E. coli reduction that is another criterion for the dental implant materials. The results was introduced the coated Ti-6Al-4V could be used as corrosion resistive and antibacterial dental implant material.