Mercapto Silane Research Articles

Covalently-Bonded Laminar Assembly of Van der Waals Semiconductors with Polymers: Toward High-Performance Flexible Devices.

Van der Waals semiconductors (vdWS) offer superior mechanical and electrical properties and are promising for flexible microelectronics when combined with polymer substrates. However, the self-passivated vdWS surfaces and their weak adhesion to polymers tend to cause interfacial sliding and wrinkling, and thus, are still challenging the reliability of vdWS-based flexible devices. Here, an effective covalent vdWS-polymer lamination method with high stretch tolerance and excellent electronic performance is reported. Using molybdenum disulfide (MoS2 )and polydimethylsiloxane (PDMS) as a case study, gold-chalcogen bonding and mercapto silane bridges are leveraged. The resulting composite structures exhibit more uniform and stronger interfacial adhesion. This enhanced coupling also enables the observation of a theoretically predicted tension-induced band structure transition in MoS2 . Moreover, no obvious degradation in the devices' structural and electrical properties is identified after numerous mechanical cycle tests. This high-quality lamination enhances the reliability of vdWS-based flexible microelectronics, accelerating their practical applications in biomedical research and consumer electronics.

Mercapto functionalized–natural zeolites/PVDF mixed matrix membrane for enhanced removal of methylene blue

Azo dye-containing wastewater is one of the most critical contaminants due to modern industrial activities, especially in the textile industry. Membrane technology has been the most prominent separation technique to alleviate these pollutants with less energy input and less raw material utilization. In this sense, zeolite-based mixed matrix membranes have offered increased filtration performance as they combine the favorable properties of polymeric membranes, molecular sieving, and the negative charge properties of zeolites. The crucial challenge is the compatibility of the inorganic filler and the polymer matrix to boost flux and rejection; otherwise, both will be dramatically compensated. Herein, low-cost natural zeolites were functionalized using mercapto silane ((3-mercaptopropyl) trimethoxysilane) agent and incorporated into porous polyvinylidene fluoride (PVDF). The resulting mixed matrix membranes showed significantly higher rejection (97.01%) and flux (37.14 L m−2h−1) compared to those of pristine PVDF membrane (rejection and flux of 82.78% and 24.05 L m−2h−1, respectively). These positive results are due to the compatibility between the mercapto-functionalized natural zeolites and PVDF matrix. In the absence of mercapto groups, the rejection could be enhanced, but the permeability decreased. In addition, the antifouling properties of the mercapto functionalized–natural zeolites/PVDF mixed matrix membrane is desirable, as indicated by the higher flux recovery ratio and lower reversible and irreversible fouling.

Molecular Layer Deposition (MLD) of a Blocked Mercapto Silane on Precipitated Silica

Chemically modified silica is widely used as a reinforcing filler in elastomers. The modification is generally done in situ while preparing the rubber. However, in order to increase the efficiency and facilitate the mixing process, the silica can be pre-treated by a 2-step molecular layer deposition. The precursors for the modification are 3-mercaptopropyl-triethoxysilane (MPTES) and octanoyl chloride (OC) to react with MPTES and form a blocked silane. The precipitated silica nanofiller was successfully treated with MPTES and showed a self-limiting behavior: saturation occurred at 2.7%. Furthermore, DRIFTS (diffuse reflectance infrared Fourier transform spectroscopy) analysis confirmed the successful deposition of MPTES on the silica surface by showing the -SH peak that appeared after the reaction of MPTES and silica. In the second step, OC was introduced to form a thioester on the surface of the MPTES-treated silica, controlling the reactivity of the mercapto group from MPTES by blocking it to prevent a negative influence on the processing behavior of the rubber. Thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy (XPS) analytical results confirmed the deposition of the blocked mercapto silane on the silica. TGA results demonstrated the self-limiting behavior of OC, and DRIFTS and XPS proved the thioester formation. A thioester peak after the 2nd reaction step with OC appeared. At the same time, the disappearance of the -SH signal from the MPTES was observed, indicating the formation of the blocked mercapto silane structure. Transmission electron microscopy results showed that the treated silica has a well-distributed carbon and sulfur deposition after MPTES/OC treatment.

Desirable bonding interactions between organo-functional triazinedithiol groups and heavy metal ions for significantly improved adsorption or dispersion property

Effective bonding interactions between various organo-functional groups and metals can contribute to novel materials or fancy performances. In order to reveal the superiority of triazinedithiolsilanes with di-sulfydryl groups over the conventional mercapto silanes with mono-sulfydryl, and amino silanes with mono-amine, for the first time, the above three silanes have been chemically anchored onto cutting-edge dendritic mesoporous silica nanospheres (DMSNs) for performance comparison. The three composite materials have been designed to serve as not only the adsorbents to remove heavy metal cadmium Cd(II), but also the catalyst-supports to load and disperse metal (noble metal Ag, Pd, and base metal Ni) nanoparticles (NPs). The abilities of triazinedithiol-functionalized DMSNs are far superior to the other two specimens both in Cd(II) capture and metal dispersion, owing to the specific nature of triazinedithiol group. The qe values of triazinedithiol-, mercapto-, and amino-functionalized DMSNs can reach to 1280, 816, 900 mg/g, respectively. Moreover, triazinedithiol-functionalized DMSNs could disperse metal NPs more uniformly that the conventional silane-modified ones. It is expected that triazinedithiolsilane compounds could faultlessly replace conventional mercapto silanes in some practical application fields and would shine brilliantly in the future.

Effect of mercapto-silanes on the functional properties of highly amorphous vinyl alcohol composites with reduced graphene oxide and cellulose nanocrystals

The reinforcing and synergistic effect of a 1D filler (cellulose nanocrystals) and of a 2D filler (reduced graphene oxide) in a high amorphous vinyl alcohol (HAVOH) polymer has been investigated. Nanocomposite films have been obtained by dissolving in water the HAVOH polymer and suitable fillers, thus leading to the formation of a very promising material for eco-friendly food packaging applications. In addition, the effect of (3-Mercaptopropyl) trimethoxysilane as crosslinking agents for the vinylalchol-based polymer has been studied. FTIR and XPS results clearly show that the presence of mercapto silane has a twofold effect. Mercapto groups have the capability to reduce chemically the graphene oxide (GO) filler to reduced graphene oxide (rGO) during the preparation of the HAVOH-based composites and to crosslink the HAVOH structure. Tensile tests show that the effect of siloxane crosslinking leads to an embrittlement of the HAVOH matrix, which is avoided when rGO e cellulose nanocrystals (CNC) are dispersed in the composites. The permeability results show that all the composites exhibit better barrier properties than pristine HAVOH. Particularly, the highest water permeability reduction of about 45% is observed for the sample containing 1% wt/wt GO and 1% wt/wt CNC. This significant drop in permeability is likely related to three concurrent effects, a) the crosslinking of HAVOH matrix, b) the binding of water molecules due to CNC presence and c) the more hydrophobic behaviour associated to a high amount of rGO.

‘Sandwich’-like hybrid ZnO thin films produced by a combination of atomic layer deposition and wet-chemistry using a mercapto silane as single organic precursor

This study describes a straightforward preparation of hybrid organic–inorganic thin films containing a stable ‘sandwich’-like structure of two atomic layer deposited (ALD) ZnO layers separated by a thin organosilane phase, which is built from a single organic component (3-mercaptopropyl)trimethoxysilane (MPTMS). Grafting of MPTMS on the first ALD ZnO layer was performed in solution and driven by the strong affinity of the terminal thiol functionality (-SH) towards ZnO. We demonstrate that under different reaction conditions, either MPTMS monolayers are prepared or a 5 nm thick cross-linked polymeric network is formed due to the self-condensation of silane, which covers the ALD ZnO surface. This film served as a soft template for the nucleation of an ALD ZnO top layer by creation of S–Zn and Si–O–Zn bonds at the upper interface, as confirmed by XPS measurements. An increase in surface roughness, as compared to the initial ZnO film, is observed after removal of the organic layer from the hybrid structure by calcination, which is accompanied by an improvement in UVA photocatalytic activity towards the degradation of methyl orange dye. Thus, MPTMS can be used as a sacrificial agent in combination with low temperature ALD processes for building rougher and photocatalytically efficient ZnO coatings.

Wettability of Primer-Treated Al2O3 Surfaces by Bisphenol A Diglycidyl Ether: Determination of the Mechanism from Molecular Dynamics Simulations and Experiments.

This study aims to develop a molecular dynamics (MD) simulation procedure to investigate the wettability of primer-treated Al2O3 surfaces by bisphenol A diglycidyl ether (BADGE) and to understand the interaction between the surface and the liquid. The MD simulation results were compared with those obtained by contact angle measurements, time-of-flight secondary ion mass spectrometry (TOF-SIMS), and atomic force microscopy (AFM) and were found to be in agreement with the experimental evaluations. The results obtained from both the MD simulations and the experiments suggest that the configuration of the primers on the surface affect its wettability. In other words, silanes lying flat on the surface, such as mercapto silane, make it easy for BADGE to access any polar functional groups of the silane, thereby leading to a strong interaction and good wettability. For amino silane, although the configuration is similar to that of mercapto silane, its amino groups are bound to the surface owing to their high polarity, which results in a reduced accessibility for BADGE and a relatively poor wettability in comparison with mercapto silane. On the contrary, for silanes that stand up on the surface, including trifluoroalkyl silane, BADGE is hindered from approaching the silanol groups and interacting with them, and the surface shows poor wettability.

REACTIVITY STUDY OF MERCAPTO–SILANE AND SULFIDE–SILANE WITH POLYMER

ABSTRACT Mercapto–silanes enable an improved silica dispersion state compared with sulfide–silanes in tire tread compounds, which causes a better balance of wet grip and rolling resistance. However, it also causes a higher Mooney viscosity and a shorter scorch time, which results in processing difficulties. The reason for this behavior is not clear. Because the already deeply investigated silica–silane reaction cannot explain the observed effects, the silane–polymer reaction was considered to be responsible and therefore has been evaluated in depth. The reaction between mercapto–silane or sulfide–silane and an olefin instead of a rubber was investigated in terms of reaction possibilities, mechanism, and kinetic aspects by varying the structure of the olefin. The results reveal that mercapto–silanes and sulfide–silanes affect olefins in different ways depending on the structure of the olefin. These results were compared with those in actual tire tread compounds in terms of the in-rubber properties such as the Payne effect and Mooney viscosity. It was confirmed that the different sulfur functions of the silanes interact in a different way with the polymer, which has a significant influence on the processability, silica dispersion state, and also rolling resistance indicator of the final rubber compound.

Robust fabrication of superhydrophobic and photocatalytic self-cleaning cotton textiles for oil–water separation via thiol-ene click reaction

Robust superhydrophobic cotton textiles exhibiting photocatalytic self-cleaning ability under UV light were successfully achieved by surface functionalization with anatase TiO2 sol and mercapto silanes, and hydrophobization with vinyl-terminated polydimethylsiloxane (V-PDMS) via thiol-ene click reaction. The modified cotton textiles not only showed outstanding water repellency with a water contact angle of 154.2°, but exhibited desirable photodegradation of oil red O by photocatalysis under UV irradiation. Moreover, the modified textiles exhibited excellent durability and stability after exposure to different severe conditions, such as acid and base solutions, organic solvents, laundering and UV exposure. The durably coated textiles manifested desirable separation performance in oil–water mixtures, and the separation efficiency was about 99.0% even after 20 times use. Cotton textiles with multi-functionality of superhydrophobicity, photocatalysis and oil-water separation are hopefully applied in a diverse range of practical applications in self-cleaning and oil-removal fields.

A novel strategy to create bifunctional silica-protected quantum dot nanoprobe for fluorescence imaging

Quantum dots (QDs) as fluorescence probes have attracted increasing attention for their fluorescence imaging applications. In this work, we developed a novel strategy to create bifunctional silica-protected QD (BSQD) nanoparticles as nanoprobes for fluorescence imaging. The thiol-ene click reaction of monounsaturated fatty acid salts with mercapto silane as an efficient method for the synthesis of the bifurcated surface modifier was presented. BSQD nanoprobes were prepared by a facile one-pot method. The whole reaction process was carried out in an aqueous solution under relatively low temperature, which makes the synthesis environment eco-friendly and the products cost-effective. The synthesized BSQD nanoprobes have a structure consisting of hydrophilic and hydrophobic arms that afforded an amphiphilic feature to the silica-protected QD (SQD) nanoparticles. The separated solid BSQD nanoprobes could be well dispersed into aqueous solution once again, and the quantum yield of the BSQD nanoprobes was higher than that of the SQD naoprobes. BSQD nanoprobes exhibited high interfacial activity, strong photostability and good biocompatibility. BSQD nanoprobes were successfully applied for fluorescence imaging. The strategy for the construction of the functionalized SQD nanoparticles provides a promising approach for modifying the surface of materials containing QDs.

Fabrication of superhydrophobic cotton fabrics by grafting of POSS-based polymers on fibers

Superhydrophobic fabrics were successfully prepared by modification of fibers with polymers containing polyhedral oligomeric silsesquioxane (POSS). The modification was conducted by chemical vapor deposition with mercapto silanes followed by click coupling with pentaerythritol tetrakis(3-mercaptopropionate) and octavinyl-POSS to form POSS-based polymers on the cotton fibers. The POSS-based polymers onto the fabric surfaces both increased the surface roughness and lowered the surface energy of the fabrics. The as-prepared superhydrophobic fabrics have excellent superhydrophobicity stability toward acid, base, salt, acetone, and N,N-dimethylformamide. In addition, the fabrics maintained superhydrophobicity under long time exposure to UV irradiation, and have better antifouling properties.

Robust multifunctional superhydrophobic fabric with UV induced reversible wettability, photocatalytic self-cleaning property, and oil-water separation via thiol-ene click chemistry

Robust superhydrophobic fabric (SF) was successfully achieved by surface modification with anatase TiO2 sol and mercapto silanes, subsequently followed by hydrophobization with perfluorooctyl methacrylate (PFOMA) via thiol-ene click reaction. The resultant SFs not only exhibited excellent superhydrophobicity with a water contact angle of 157.7° and a water shedding angle of 4°, but also showed the considerable photocatalytic activity by the degradation of oil red O under UV irradiation. Moreover, the SFs exhibited a wetting transition from a superhydrophobic state to a superhydrophilic state by the alternation of UV exposure and thermal treatment. The SF could be utilized to separate oil-water mixture owing to its superhydrophobicity and superoleophilicity. Importantly, the SFs were tolerant towards strong acidic or alkaline environments, corrosive organic solvents, laundering, and mechanical abrasion. In addition, this facile preparation process could impart the superhydrophobicity to other substrates (such as PET fabrics, nonwoven fabrics, and sponges). Therefore, superhydrophobic materials with multi-functionality of UV induced reversible wettability, photocatalytic self-cleaning property, and oil-water separation are regarded as promising candidates for a wide range of applications.

Emerging clay-aryl-gold nanohybrids for efficient electrocatalytic proton reduction

There is an ever growing demand for renewable sources of energy to replace conventional fossil fuels. One of the alternatives is usage of hydrogen production by electrochemical hydrogen evolution reaction (HER). Toward this end, we have successfully prepared a novel, robust electrocatalyst for HER containing Au nanoparticles dispersed on a natural bentonite using a simple one-pot reduction process. It is one of the most effective ways to minimize Au nanoparticle production cost, stability and usage.Bentonite clay was first modified using two coupling agents (mercaptosilane (MPS) or the diazonium salt of diphenyl aminoaniline (DPA)) to increase interlamellar spacing distance and to provide anchoring sites for the perfluorinated diazonium tetrachloroaurate (III) salt used as a unique source of zero-valent gold nanoparticles dispersed on bentonite surface. Successful intercalation was confirmed by the detection of F1s peak in X-ray photoelectron spectroscopy (XPS) at ∼689 eV, in line with fluorine in CF bonds, and the reduction of gold (III) into metallic gold. Both nanohybrids showed efficient electrochemical activity for HER in acidic condition (0.1 M H2SO4) with high current density up to −25 mA.cm−2 at −1 V and 0.148 mV onset. Negligible decreasing in current density and slight shift in onset was observed after 1000 cycles. The results obtained so far open new avenues for the preparation of low cost, efficient and stable HER catalyst on the one hand, and will contribute to the knowledge of the surface chemistry of the diazonium salts, on the other hand.

Resin Bonding to Type IV Gold Alloy Conditioned with a Novel Mercapto Silane System: Effect of Incorporation of a Phosphate Monomer.

Self-assembled monolayers of thiols have been used to link a range of materials to planar gold surfaces or gold nanoparticles in nanoscience and nanotechnology. Novel mercapto silane systems are a promising alternative to dental noble metal alloys for enhanced resin bonding durability Goldbased alloys for full-cast restorations contain various base metal elements, which may bond to acidic functional monomers chemically, in addition to noble metal elements. This study examined how the additional incorporation of a phosphate monomer (di-2-hydroxyethyl methacryl hydrogenphosphate, DHP) into novel mercapto silane primer systems affected the resin bond strength to a type IV gold alloy pretreated with the primers. One of three commercial primers (Alloy Primer and M. L. Primer) and three experimental primer systems ((1) blend of γ-mercaptopropyltrimethoxysilane (SPS) and γ-methacryloxypropyltrimethoxysilane (MPS) (both 1.0 wt%), (2) 1.0 wt% DHP-containing primer, and (3) blend of SPS, MPS, and DHP (each 1.0 wt%)) was applied to the alloy surfaces after sandblasting. Resin cylinders (diameter: 2.38 mm) were bonded to the surfaces and light-cured. All bonded specimens were stored in water at 37 °C for 24 h and then half of them additionally water immersed for 7 days (37 °C) and thermocycled 10,000 times before the shear bond strength test (n = 10). The mercapto silane systems (SPS + MPS) were found to show superior resin bonding durability to the commercial primers and the only DHP-containing primer, regardless of additional incorporation of the phosphate monomer.

Facile generation of robust POSS-based superhydrophobic fabrics via thiol-ene click chemistry

Robust polyhedral oligomeric silsesquioxane (POSS)-based superhydrophobic fabrics were successfully generated by surface modification of fibers with mercapto silanes followed by click coupling with methacryl-heptaisobutyl POSS (MAPOSS). MAPOSS grafted onto the fabric surfaces not only increased the surface roughness but also lowered the surface energy of fabric, resulting in superhydrophobicity with a water contact angle of 159° and a sliding angle of 7°. Importantly, the as-prepared superhydrophobic cotton fabric is tolerant to corrosive liquids, UV irradiation, high temperature environment, ultrasonic washing and mechanical abrasion. And the as-prepared superhydrophobic fabric could be used as an adsorbent material for removing oil from water. In addition, MAPOSS could be easily grafted onto other porous substrates (including but not limited to polyester fabrics, filter papers and melamine sponges) to endow these materials with high hydrophobicity. Therefore, this facile, environmentally friendly, low cost and versatile method offers great technological promise in the preparation of robust superhydrophobic coatings on a large scale.

SILANIZATION CHARACTERIZATION AND COMPOUND PROPERTIES OF SILICA-FILLED RUBBER CONTAINING A BLOCKED MERCAPTO SILANE

ABSTRACT The silanization of silica-filled compounds containing a blocked mercapto silane, 3-octanoylthiopropyltriethoxysilane (OTPTES), was characterized by evaluating the exposed silica surface covered by the silane. Measurements of silica flocculation upon heating were employed to estimate the exposed silica surface coverage for silanization calculation. Compounds were prepared with various mechanical and thermal histories by adjusting the mixing time and temperature. Dynamic hysteretic properties at 0 and 60 °C in conjunction with strategic mechanical properties were correlated with the degree of silanization for each compound. Well-balanced properties in processability, reinforcement, and performance were readily attained through the study of the silanization/structure/property relationship. Experimental data showed that an 84% degree of silanization was needed to attain the optimal properties of compounds containing OTPTES regardless of the mixing protocol. Consistent compound properties may be realized by using a designated degree of silanization as a key mixing parameter for effective quality control in tire production.

Structured textile surfaces for easy-to-clean properties towards dry soil

Soiling of (textile) surfaces is a big issue as it reduces the users comfort and may decrease the conservation of value of the product. In automotive, interior parts of head lining and side lining are soiled by airborne dust, brought into the car by the ventilation system. To overcome these problems, textiles can be functionalized with anti-soiling finishes. However, commercial anti-soiling products often are very effective against liquid soil but less effective against dry soil. Repellency of this type of soil (e.g. street dust) can be achieved by (nano)structured surfaces which reduce the contact area between textile and dirt particle.In this research project textile surfaces with easy-to-clean properties for dry soil were prepared. Textile samples were functionalized with mixtures of structuring hydrophilic silica particles (HDK-C10) and binder systems based on silanes. To determine the easy-to-clean effect, samples were soiled with standard soil using a modified filter test rig and were vacuum cleaned afterwards. Scanning electron microscopy (SEM) was used to analyze particle size and distribution. The low viscosity of the components of the binder system enabled film formation around each single fiber. Film properties could be adjusted by different functionalities of silanes. Especially, silica particles in combination with a mixture of a vinylsilane (VTEO) and a mercapto silane (MS) showed good cleaning properties. This effect remains for several soiling and cleaning cycles which demonstrates the permanence of the finishing.

Surface modified palygorskite nanofibers and their applications as reinforcement phase in cis-polybutadiene rubber nanocomposites

In this paper, palygorskite nanofibers modified by liquid rubbers and mercapto silane coupling agent were used as reinforcement phase in the preparation of cis-polybutadiene rubber nanocomposites. The morphologies, structures, and performances, of the nanocomposite rubbers and modified palygorskite nanofibers were characterized. Results show that the liquid rubber coated palygorskite (PALHT) nanofibers reinforced cis-polybutadiene rubber nanocomposites exhibit superior performance, which indicates that liquid rubber coating is essential for optimizing the performance of the modified palygorskite nanofibers. This is attributed to penetration of organic molecules into the interlayer of palygorskite, resulting in formation of a three-dimensional network structure during the vulcanization. It is confirmed by the evidences that the characteristic diffraction peaks of palygorskite become weak and broadened distinctly, with a wide amorphous characteristic curve emerging around 15°–30°. The crosslinking force is much larger than that of the binding energy among the palygorskite crystal layers, which promotes peeling on the crystal face. This work demonstrates a feasible way to obtain an island-structured reinforced composite consisting of 3D network structure units.

Durability of resin bond strength to dental noble metal–ceramic alloys conditioned with novel mercapto silane-based primer systems

The purpose of this study was to investigate the efficacy of novel mercapto silane-based experimental primers on the resin bonding and its durability to dental noble metal–ceramic alloys in comparison with that of commercial primers. Disc-shaped gold–platinum–palladium, gold–palladium–silver, and palladium–silver alloy specimens were used as the adherents after air-abrasion. One of three commercial primers (M.L. Primer, Single Bond Universal, and All-Bond Universal) and two experimental primer systems (2-step application with γ-mercaptopropyltrimethoxysilane and then γ-methacryloxypropyltrimethoxysilane and a blend of the two silanes) was applied to each alloy. Resin cylinders with a diameter of 2.38 mm were bonded to the surfaces and light-cured. All bonded specimens were stored in water at 37 °C for 24 h and then half of them additionally water immersed for 7 days (37 °C) and then thermocycled 10,000 times before the shear bond strength test (n = 10). The surface energy parameters for unprimed and primed alloy surfaces were calculated based on the contact angle measurements. The bond strength data were non-parametrically analyzed at α = 0.05. Regardless of the alloy type, both mercapto silane systems equally and consistently showed superior bonding durability to the commercial primers. Pearson correlation analyses revealed moderate to strong, significant correlations between the surface energy parameters and the bond strength values. The two novel mercapto silane systems are a promising alternative for enhanced durability of resin bonding to dental noble metal–ceramic alloys.

The Effect of Novel Mercapto Silane Systems on Resin Bond Strength to Dental Noble Metal Alloys.

Self-assembled monolayers of thiols (RSH), which are key elements in nanoscience and nanotechnology, have been used to link a range of materials to planar gold surfaces or gold nanoparticles. In this study, the adhesive performance of mercapto silane systems to dental noble metal alloys was evaluated in vitro and compared with that of commercial dental primers. Dental gold-palladium-platinum (Au-Pd-Pt), gold-palladium-silver (Au-Pd-Ag), and palladium-silver (Pd-Ag) alloys were used as the bonding substrates after air-abrasion (sandblasting). One of the following primers was applied to each alloy: (1) no primer treatment (control), (2) three commer- cial primers: V-Primer, Metal Primer II, and M.L. Primer, and (3) two experimental silane primer systems: 2-step application with 3-mercaptopropyltrimethoxysilane (SPS) (1.0 wt%) and then 3-methacryloxypropyltrimethoxysilane (MPS) (1.0 wt%), and a silane blend consisting of SPS and MPS (both 1.0 wt%). Composite resin cylinders with a diameter of 2.38 mm were bonded to the surfaces and irradiated for 40 sec using a curing light. After storage in water at 37 °C for 24 h, all the bonded specimens were thermocycled 5000 times before the shear bond strength test. Regardless of the alloy type, the mercapto silane systems (both the 2-step and blend systems) consistently showed superior bonding performance than the commercial primers. Contact angle analysis of the primed surfaces indicated that higher resin bond strengths were produced on more hydrophilic alloy surfaces. These novel mercapto silane systems are a promising alternative for improving resin bonding to dental noble metal alloys.