PDMS Resin Research Articles

A novel surgical diamond spherical wheel to prevent bone adhesion with superhydrophobic and super-slippery coatings

Ordinary commercial diamond spherical wheels are extensively used in bone grinding surgeries. However, a persistent issue arises from bone debris adhering to the wheel surface, leading to elevated temperatures during the bone grinding process. To address this, the study developed a novel spherical wheel with a superhydrophobic and super-slippery coating to prevent the bone debris adhesion. Initially, a superhydrophobic and super-slippery coating was successfully designed and fabricated with mixture of ODA-GO, PDMS, KH-550, and epoxy resin E44. The coating's surface morphology, chemical composition, and durability were comprehensively characterized. Subsequently, the coating was applied to diamond spherical grinding wheels for bone grinding experiments. The results demonstrate that a coating with exposed ODA-GO forms a rough structure with optimal component parameters, achieving a contact angle of 158° and a sliding angle of 4.2°. Furthermore, the superhydrophobic and super-slippery coating exhibits exceptional wear and slipperiness resistance even after 100 cycles, maintaining a contact angle of 135° and a sliding angle of 8.5°. The use of this novel spherical wheel significantly mitigates bone debris adhesion. This study not only provides valuable insights into the mechanisms of anti-adhesion but also introduces a promising technique for enhancing the performance of diamond spherical wheels.

High crystalline LDHs with strong adsorption properties effectively remove oil and micro-nano plastics

Micro-nano plastics are a growing threat to the Earth's ecosystems and to human beings, and they are not easily detected and are highly susceptible to spreading and transportation. Based on the tenet of cleaner production, there is an urgent need to recover oil and micro-nano plastics in water. In this paper, nanolayered double hydroxides (LDHs) with high crystallinity were obtained by hydrothermal method and mixed with PDMS and epoxy resin, and after dip-coating on polyurethane sponges, a kind of green and environmentally friendly PLT@PU sponge was obtained. Thanks to the bonding ability of the epoxy resin, the LDHs can well provide nanostructures and combine with PDMS to provide superhydrophobicity. Based on superhydrophobicity and capillary action, the PLT@PU sponge can quickly adsorb light/heavy oils in water. Based on electrostatic attraction, capillary action, hydrophobicity and chemical bonding, PLT@PU sponge can remove micro and nano plastics in water well. In addition, simulation analysis was performed by Langmuir model and Freundlich isothermal adsorption model. This homogeneous, mechanically durable and reusable excellent adsorbent has a wide range of application scenarios.

Characterization of Superhydrophobic Coatings Based on PDMS and MQ Resin on Textured Surfaces

Characterization of Superhydrophobic Coatings Based on PDMS and MQ Resin on Textured Surfaces

Enhancement of Isotropic Heat Dissipation of Polymer Composites by Using Ternary Filler Systems Consisting of Boron Nitride Nanotubes, h-BN, and Al2O3.

In this research article, a poly(dimethylsiloxane) (PDMS)-based composite was postulated adapting an interactive ternary filler system consisting of Al2O3, hexagonal boron nitride (h-BN), and boron nitride nanotubes (BNNT) to construct a continuous three-dimensional (3D) structure for thermal attenuation. Al2O3 was imposed as a main filler, while h-BN and BNNT were assimilated to form interconnected heat conduction pathways for effective thermal dissipation. The structured framework articulates a profound improvement in isotropic thermal conductivity considering both axial and radial heat dissipation. The presence of h-BN entails uniform heat distribution in a planar mode, eliminating the occurrence of hotspots, while BNNT constructed a connecting phonon pathway in various directions, which insinuates effective overall thermal transport. The generated ternary filler composites attained an isotropic ratio of 1.35 and a thermal conductivity of 7.50 W/mK, which is a 36-fold (∼3650%) increase compared to neat PDMS resin and almost 3-fold (∼297%) that of the Al2O3 unary filler composite and ∼53% that of its binary counterpart, partaking interfacial thermal gaps of ∼36.15 and ∼62.24% on practical heating performance relative to its counterparts. Moreover, the incorporation of BNNT on a traditional spherical and planar filler offers an advantage not only in thermal conductivity but also in thermal and structural stability. Improvement in thermal stability is stipulated due to a melting point (Tm) shift of ∼11 °C upon the assimilation of BNNT. Mechanical permeance reinforcement was also observed with the presence of BNNT, showcasing a 31.5% increase in tensile strength and a 53% increase in Young's modulus relative to the singular filler composite. This exploration administers a new insight into heat dissipation phenomena in polymeric composites and proposes a simple approach to their design and assembly.

Mechanically robust liquid-embedded coating with anti-icing/deicing durability

The slippery liquid-infused porous surface has been concerned for their excellent icephobicity. However, unavoidable lubricant consumption can result in the failure of anti-icing/deicing properties. Traditional coatings cannot escape the choice between anti-icing/deicing property and mechanical performance. This paper reports mechanically robust liquid-embedded coating (MRLC) with anti-icing/deicing durability. The MRLC is prepared by a facile one-step method via adding silica and silicone oil in the process of co-curing PDMS and epoxy resin. The prepared MRLC-5–5–80 have excellent anti-fouling, self-cleaning, anti-icing/deicing and anti-frost properties in high humidity and low temperature environment. This surface remained free of liquid residue and ice within 30 min in supercooled water droplet impact test. In addition, this coating exhibited a low τice (5.48 kPa) and excellent durability. The PDMS polymer and fumed silica serve as oil storage reservoir for the coating to ensure durability, and the anti-icing/deicing durability can be restored by self-replenishing and external-replenishing. More importantly, the coating guarantees anti-icing/deicing durability while possessing excellent mechanical robustness. The liquid repellency and anti-icing/deicing performance still prevailed after various mechanical damages. This method opens the door for production of durable and mechanically robust for various anti-icing/deicing practical applications.

Improved Mechanical and Ablative Properties of PDMS Coatings Incorporating Epoxy as a Suspended Chain

Flexible thermal protection materials with excellent mechanical and ablative properties were one of the key components in promoting the development of a new generation of aircraft. In the present work, a robust, strongly adhesive, and ablation-resistant PDMS coating was prepared through the covalent connection between PDMS and vinyl-functionalized epoxy resin (EAP) by hydrosilylation. The EAP synthesized by molecular design was uniformly dispersed in the PDMS matrix as an island phase-separation structure. The tensile strength, elongation at break, and shear strength of EAP-modified PDMS (EAP@PDMS) were significantly increased by 575%, 155%, and 183%, respectively, when compared with pure PDMS. Besides, the linear ablation rate (LAR) of EAP@PDMS was greatly declined, which was 80.1% lower than that of pure PDMS, exhibiting excellent ablation resistance. This work opened an avenue toward developing flexible thermal protection coatings with excellent mechanical and ablative properties for aerospace applications.

Effect of PDMS Viscosity and Additive Amount of Curing Agent Solution on the Mechanical Properties of PDMS Fouling Release Coating

The mechanical properties of PDMS fouling release coatings have a very important effect on actual use. The coating was designed and prepared to study the effect of viscosity of PDMS resin and additive amount of curing agent on the mechanical properties of the coating. The cross-linking index of the coating was used to analyze the mechanical properties of the coatings. The results indicate that the mechanical properties of the coating formed by the crosslinking reaction with a high viscosity of PDMS resin are better. Despite the different viscosity of PDMS resin, the coating has the best mechanical properties, when the mole ratio of PDMS to TEOS is 1: 18.24.

Advancing 3D-Printed Microfluidics: Characterization of a Gas-Permeable, High-Resolution PDMS Resin for Stereolithography.

The rapid expansion of microfluidic applications in the last decade has been curtailed by slow, laborious microfabrication techniques. Recently, microfluidics has been explored with additive manufacturing (AM), as it has gained legitimacy for producing end-use products and 3D printers have improved resolution capabilities. While AM satisfies many shortcomings with current microfabrication techniques, there still lacks a suitable replacement for the most used material in microfluidic devices, poly(dimethylsiloxane) (PDMS). Formulation of a gas-permeable, high-resolution PDMS resin was developed using a methacrylate–PDMS copolymer and the novel combination of a photoabsorber, Sudan I, and photosensitizer, 2-Isopropylthioxanthone. Resin characterization and 3D printing were performed using a commercially available DLP–SLA system. A previously developed math model, mechanical testing, optical transmission, and gas-permeability testing were performed to validate the optimized resin formula. The resulting resin has Young’s modulus of 11.5 MPa, a 12% elongation at break, and optical transmission of >75% for wavelengths between 500 and 800 nm after polymerization, and is capable of creating channels as small as 60 µm in height and membranes as thin as 20 µm. The potential of AM is just being realized as a fabrication technique for microfluidics as developments in material science and 3D printing technologies continue to push the resolution capabilities of these systems.

Noncontact photoacoustic imaging based on optical quadrature detection with a multiport interferometer.

A noncontact photoacoustic imaging method based on optical quadrature detection is proposed. The photo-induced acoustic signal is detected by an optical method without contacting the specimen. By utilizing the intrinsic phase difference of a multiport optical interferometer, the quadrature signal of a conventional interferometric signal could be obtained. With this quadratic signal pair, we could reconstruct the photoacoustic signal without suffering from the initial phase drift that usually occurs in a conventional interferometric system. The performance of the proposed system is verified by imaging human hairs embedded in a polydimethylsiloxane resin block. The system's lateral and axial resolutions are measured to be 84 and 86μm at a 1.5mm depth of a PDMS resin block, respectively. The experimental result is good enough to distinguish the hairs staggered in depth.

Highly stretchable and ultrathin nanopaper composites for epidermal strain sensors

Multifunctional electronics are attracting great interest with the increasing demand and fast development of wearable electronic devices. Here, we describe an epidermal strain sensor based on an all-carbon conductive network made from multi-walled carbon nanotubes (MWCNTs) impregnated with poly(dimethyl siloxane) (PDMS) matrix through a vacuum filtration process. An ultrasonication treatment was performed to complete the penetration of PDMS resin in seconds. The entangled and overlapped MWCNT network largely enhances the electrical conductivity (1430 S m−1), uniformity (remaining stable on different layers), reliable sensing range (up to 80% strain), and cyclic stability of the strain sensor. The homogeneous dispersion of MWCNTs within the PDMS matrix leads to a strong interaction between the two phases and greatly improves the mechanical stability (ca. 160% strain at fracture). The flexible, reversible and ultrathin (<100 μm) film can be directly attached on human skin as epidermal strain sensors for high accuracy and real-time human motion detection.

Desktop-Stereolithography 3D-Printing of a Poly(dimethylsiloxane)-Based Material with Sylgard-184 Properties.

The advantageous physiochemical properties of poly(dimethylsiloxane) (PDMS) have made it an extremely useful material for prototyping in various technological, scientific, and clinical areas. However, PDMS molding is a manual procedure and requires tedious assembly steps, especially for 3D designs, thereby limiting its access and usability. On the other hand, automated digital manufacturing processes such as stereolithography (SL) enable true 3D design and fabrication. Here the formulation, characterization, and SL application of a 3D-printable PDMS resin (3DP-PDMS) based on commercially available PDMS-methacrylate macromers, a high-efficiency photoinitiator and a high-absorbance photosensitizer, is reported. Using a desktop SL-printer, optically transparent submillimeter structures and microfluidic channels are demonstrated. An optimized blend of PDMS-methacrylate macromers is also used to SL-print structures with mechanical properties similar to conventional thermally cured PDMS (Sylgard-184). Furthermore, it is shown that SL-printed 3DP-PDMS substrates can be rendered suitable for mammalian cell culture. The 3DP-PDMS resin enables assembly-free, automated, digital manufacturing of PDMS, which should facilitate the prototyping of devices for microfluidics, organ-on-chip platforms, soft robotics, flexible electronics, and sensors, among others.

Self-healing three-dimensional bulk materials based on core-shell nanofibers

In this study, electrospun core-shell nanofibers containing healing agents are embedded into a three-dimensional bulk matrix in a simple versatile process. Two types of the healing agents (resin monomer and cure) are encapsulated inside the nanofiber cores. The core-shell fibers are encased in the macroscopic three-dimensional bulky material. To achieve this goal, the electrospun core-shell fibers containing two components of PDMS (either resin monomer or cure) are directly embedded into an uncured PDMS bath and dispersed there, essentially forming a monolithic composite. For the evaluation of the self-healing features, the interfacial cohesion energy is measured at the cut surface of such a material. Namely, the bulk of the prepared self-healing material is entirely cut into two parts using a razor blade and then re-adhered due to the self-curing process associated with the released healing agents. The results reveal that the self-healing fiber network works and releases a sufficient amount of resin monomer and cure at the cut surface to facilitate self-healing. In addition, chopped into short filaments core-shell fibers were embedded into highly porous sponge-like media. After a mechanical damage in compression or shearing fatigue, this sponge-like material also revealed restoration of stiffness due to the released self-healing agents. The sponges revealed a 100% recovery and even enhancement after being damage in the cyclic compression and shearing tests, even though only 0.086% of the healing agents were embedded per sponge mass and finely dispersed in it.

Preparation and Characterization of a Novel Hydrogel-Based Fouling Release Coating

With the rapid development of marine transportation industry, biological fouling not only affects the speed of navigation but also highly increases fuel consumption. In the paper, a novel hydrogel-based fouling release coating is developed to address the issue by a combination of non-stick property with a low surface tension of the coating. A hydrogel-based silicone fouling release coating was synthesized and two kinds of different intermediate coatings were studied to give a proper match as the tie layer between the substrate coated with primer and the hydrogel silicone on the surface. The adhesion strength, surface tension as well as surface topography of the fouling release coating were studied. The corrosion resistance and anti-fouling performance of the substrates sprayed with the coating were characterized by salt spray test and immersion test in a simulated marine system. The results show that the adhesion between the substrate and the fouling release coating is grade two measured by grid test. The water contact angle of the coating is 104.8o and Rz of the coating is 10.71μm. The specimen is intact after 1000 hours under salt spray test. No diatom was found settled on the specimens in a simulated static marine system while a little diatom was observed on the specimens in a simulated dynamic marine system. It has been found that the intermediate coating comprising of epoxy resin gives proper match between the primer and the fouling release coating consisting of PDMS resin. The coating exhibits superior anti-fouling performance under stationary state.

Surface Modification of PDMS and Plastics with Zwitterionic Polymers.

Surface modification of PDMS, polycarbonate, and acrylic resin was examined using various methacryl polymers bearing sulfobetaine, phosphoryl choline, and oligoethylene glycol units. We have found that zwitterionic polymers are adsorbed on the PDMS surface treated with plasma. The surface of PDMS is stable to keep high hydrophilicity after a month of the modification. On the other hand, one of sulfobetaine polymers showed distinguished adsorption behavior in the case of polycarbonate surface treated with plasma. Suppression effect for nonspecific adsorption of BSA was evaluated using polycarbonate and acrylic resin modified with the polymers. The modified surfaces showed suppression effect for nonspecific adsorption of BSA compared with the surface only treated with plasma.

Properties of Stretchable Graphite Intercalation Compound/Polydimethylsiloxane Composites after Cyclic Tensile Strain of 20%

The expanded graphite intercalated compound (GIC)/poly(dimethyl siloxane) (PDMS) composites were pre- pared and the effects of cyclic stretching on the morphology, thermal conductivity and surface resistance of the com- posites were investigated. PDMS resin did not penetrate into the pores of the expanded GIC. The uniform distribution and spatially connected GICs in the PDMS matrix resulted in improved thermal conductivity and decreased sheet resis- tance. The thermal conductivity and sheet resistance of GIC(20 wt%)/PDMS composites were changed after 1000 cycles of 20% tensile strain from 0.80 W/mK and 6×10 Ω/sq to 0.69 W/mK and 3.04×10 Ω/sq, respectively. The decreased thermal conductivity and the increased sheet resistance of the composites after cyclic stretching was attributed to the for- mation of the interfacial crack between PDMS matrix and the GIC filler.

Manufacturable conducting rubber ambers and stretchable conductors from copper nanowire aerogel monoliths.

We report on a low-cost, simple yet efficient strategy to fabricate ultralightweight aerogel monoliths and conducting rubber ambers from copper nanowires (CuNWs). A trace amount of poly(vinyl alcohol) (PVA) substantially improved the mechanical robustness and elasticity of the CuNW aerogel while maintaining a high electrical conductivity. The resistivity was highly responsive to strains manifesting two distinct domains, and both followed a power law function consistent with pressure-controlled percolation theory. However, the values of the exponents were much less than the predicted value for 3D systems, which may be due to highly porous structures. Remarkably, the CuNW-PVA aerogels could be further embedded into PDMS resin, forming conducting rubber ambers. The ambers could be further manufactured simply by cutting into any arbitrary 1D, 2D, and 3D shapes, which were all intrinsically conductive without the need of external prewiring, a condition required in the previous aerogel-based conductors. The outstanding electrical conductivity in conjunction with high mechanical compliance enabled prototypes of the elastic piezoresistivity switches and stretchable conductors.

A simple method for fabrication of filler-free stretchable polydimethylsiloxane surfaces

We propose a simple method to elaborate a filler-free stretchable PDMS surface strong enough to resist to successive elongation/retraction cycles even at high degree of stretching. It consists in creating free radicals on a filler-containing PDMS surface by argon plasma exposure and reacting them with a filler-free PDMS resin during the crosslinking step. Changes of physical and chemical properties upon plasma modification are monitored by FTIR and XPS spectroscopies, contact angle measurements and atomic force microscopy. Electron spin resonance (ESR) is used to identify the nature of radicals involved in interfacial bonding. Although a brittle silica-like layer is created on the filler-containing PDMS surface after plasma treatment, an increase in the PDMS/PDMS interfacial strength is observed and a high interfacial resistance has been found under elongation/retraction (stretching/relaxation) cycles.

Pervaporation separation of organic azeotrope using poly(dimethyl siloxane)/clay nanocomposite membranes

The paper describes the preparation of poly(dimethyl siloxane) (PDMS)/clay nanocomposite membranes by in situ crosslinking of vinyl terminated PDMS (V-PDMS) resin in the presence of clay content varying from 1% w/w to 10% w/w in order to evaluate the influence of layered silicate on pervaporation characteristics of PDMS. Two commercial clays, Cloisite 30B and Nanomer 1.30P functionalized with polar and nonpolar surfactants were chosen for this purpose and PDMS membranes were prepared in the absence/or presence of varying amounts of different clays. Structural, mechanical and thermal characterization was done using Fourier transform infrared spectroscopy (FTIR), tensile testing system and thermogravimetric analyzer. Morphological characterization using X-ray diffraction and transmission electron microscopy showed intercalation or partial exfoliation of silicate layers. Surface characterization using scanning electron microscope showed an uniform dispersion of nanoclays in PDMS matrix. Two nanocomposite membranes having PDMS/nanoclay (10% w/w) were selected based on their mechanical properties and evaluated for their performance in separating azeotropic toluene/methanol mixture. Composite membranes showed higher selectivity as compared to neat PDMS and toluene was a preferred permeant. The total flux for composite membranes was lower as compared to PDMS membrane. This study demonstrates that polymer nanocomposite membranes could be an alternative way for tuning between permeation flux and selectivity in addition to enhanced thermal and mechanical properties.

Self-healing of a high temperature cured epoxy using poly(dimethylsiloxane) chemistry

A high temperature cured self-healing epoxy is demonstrated by incorporating microcapsules of poly(dimethylsiloxane) (PDMS) resin and separate microcapsules containing an organotin catalyst. Healing is triggered by crack propagation through the embedded microcapsules in the epoxy matrix, which releases the healing agents into the crack plane initiating crosslinking reactions. A series of tapered double-cantilever beam (TDCB) fracture tests were conducted to measure virgin and healed fracture toughness. Healing efficiencies, based on fracture toughness recovery, ranged from 11 to 51% depending on the molecular weight of PDMS resin, quantity of healing agent delivered, and use of adhesion promoters.

Comparison of three different scales techniques for the dynamic mechanical characterization of two polymers (PDMS and SU8)

In this article the dynamic mechanical characterization of PDMS and SU8 resin using dynamic mechanical analysis, nanoindentation and the scanning microdeformation microscope have been presented. The methods are hereby explained, extended for viscoelastic behaviours, and their compatibility underlined. The storage and loss moduli of these polymers over a wide range of frequencies (from 0.01 Hz to some kHz) have been measured. These techniques are shown fairly matching and the two different viscoelastic behaviours of these two polymers have been exhibited. Indeed, PDMS shows moduli which still increase at 5 kHz whereas SU8 ones decrease much sooner. From a material point of view, the Havriliak and Negami model to estimate instantaneous, relaxed moduli and time constant of these materials has been identified.