Fluorosilicone Oil Research Articles

Superhydrophobic and oleophilic polyurethane sponge for oil/water separation

Massive oil spills and the discharge of oily wastewater not only inflict permanent damage upon ecosystems but also pose a significant threat to human health. Developing a low-cost functional material for efficient oil-water separation of multi-type of oil-water mixtures, such as free oil, dispersed oil, and emulsion oil, has always been a difficult challenge. In this work, the rough structure was successfully constructed by etching the surface of polyurethane (PU) sponges with sodium fluoride (NaF) aqueous solution. The introduction of hydroxyl-terminated fluorosilicone oil (HTFO) with hydrophobicity on the surface of PU sponge was followed by using glycidyl methacrylate (GMA) as the "bridge". The modified PU (RSS-PU) sponge had a contact angle of 151 ± 2° for water and 0 ° for oil. In addition, the RSS-PU sponge also demonstrated excellence oil sorption ability, its sorption of vegetable oils reached 47.90 g/g, for organic solvents the highest 72.06 g/g, maintaining its oil-absorbing capacity over multiple cycles. Impressively, the superhydrophobic/superoleophilic properties of the RSS-PU sponge has good durability and chemical stability. Meanwhile the superhydrophobic/superoleophilic characteristics of the RSS-PU sponge enable to effectively separate oil-water mixtures, and achieve separation efficiencies of 94.13% and 82.74% for toluene and water mixture without and with surfactants for emulsifying.

Synergistic effect of micro–nano surface structure and surface grafting on the efficient fabrication of durable super-hydrophobic high-density polyethylene with self-cleaning and anti-icing properties

An industrialized polymer molding technology that combines water-soluble etching and surface chemical reactions was proposed for preparing a superhydrophobic high-density polyethylene (H@G-E/HDPE) sheet. HDPE sheets were etched with a saturated aqueous solution of NaF to create a rough surface, after which glycidyl methacrylate (GMA) was introduced onto the HDPE surface to create a large number of reactive sites on the inert surface of HDPE, enabling further grafting of a low-surface-energy hydroxyl-terminated fluorosilicone oil (HTFO) onto the HDPE surface. The H@G-E/HDPE sheet exhibited high hydrophobicity, with a water contact angle (WCA) of 158 ± 1° and sliding hysteresis angle (SHA) of 8 ± 1°. The sheet also exhibited good durability, with a WCA greater than 150° after 240 h of strong stirring in water or abrasion with sandpaper for 120 rubs. The H@G-E/HDPE sheet exhibited chemical resistance and maintained super-hydrophobicity even after 24 h of immersion in a strong acid/alkali solution. Furthermore, the super-hydrophobicity of the as-obtained H@G-E/HDPE sheet was maintained upon impact with water droplets at 0.77 m/s, along with low ice adhesion at 11.64 ± 1.74 KPa, a significantly longer icing delay time, and self-cleaning properties. The developed superhydrophobic H@G-E/HDPE sheet featuring low-cost and efficient fabrication has promising applications in many industries, such as pipelines, membranes, packaging, and electronic equipment.

The Compatibility of Three Silicone Oils with Polydimethylsiloxane and the Microstructure and Properties of Their Composite Coatings.

The compatibility of three types of silicone oil with polydimethylsiloxane, the phase separation of their mixture and the microstructure and properties of their composite coatings were investigated. The existing form of silicone oil in the coating and the precipitation behavior were also studied. The compatibility observed experimentally of the three silicone oils with PDMS is consistent with the results of the thermodynamic calculation. The silicone oil droplet produced by phase separation in the mixture solution can keep its shape in the cured coating, also affecting the microstructure and mechanical properties of the coating. It was found that methyl silicone oil and methyl fluoro silicone oil do not precipitate on the surface, and they have no effect on the surface properties of the coating. In contrast, phenyl silicone oil has obvious effect on the surface, which makes the water contact angle and diiodomethane contact angle of the coating decrease significantly.

Preparation and properties of fluorosilicone polyether polyurethane underwater acoustically transparent encapsulant

Fluorosilicone polyether polyurethane (FSPU) was successfully prepared from polytetramethylene glycol, hydroxyl fluorosilicone oil, toluene diisocyanate and chain extender 2,4-diamino-3,5-dimethylthiotoluene. The obtained material was characterized by Fourier transform infrared spectroscopy, dynamic mechanical analysis and scanning electron microscopy. And the water resistance, mechanical and acoustic performance of the materials were tested by video optical contact angle measuring instrument, electronic universal testing machine and sound field, respectively. The results showed that the glass transition temperature of FSPU was lowered and the cold resistance was improved with the addition of hydroxyl fluorosilicone oil. When the amount of hydroxyl fluorosilicone oil was 40 wt%, the water contact angle of FSPU increased to 113.6°, and the water absorption reached a minimum of 0.7%. Compared with polyurethane, the hydrophobic performance of FSPU was significantly improved. The insertion loss of FSPU-40 at 1000 kHz was only 220.60 dB/m, which was 68.7% lower than that of polyurethane. Above all, FSPU has excellent water resistance, cold resistance and acoustic performance, and is an ideal material for underwater acoustically transparent encapsulant.

Crude Oil Foams: Testing and Ranking of Antifoams with the Depressurization Test

The addition of chemicals is the most widely applied solution to prevent the formation of foam or to destroy it immediately after its generation as a result of its simplicity and efficiency. Among the different chemicals that can be used as antifoams or defoamers, polydimethylsiloxane (PDMS) oils are the most common, followed by fluorosilicone oils for the most severe cases. Nonetheless, there is no clear management on the selection of these additives; therefore, it is still based on a trial-and-error basis. For this reason, we have studied the properties and effectiveness of different chemical additives by defining two parameters based on the logistic model developed for the study of the defoaming kinetics of crude oil foams formed by depressurization: the effect on the foamability or antifoamability effect (AE) and the effect on foam stability or destabilization effect (DE). Finally, we have tried to go further in the understanding of the mechanisms involved in foam breaking, looking for similitudes on ...

Preparation and tribological properties of fluorosilane surface-modified lanthanum trifluoride nanoparticles as additive of fluoro silicone oil

Abstract LaF 3 nanoparticles surface-modified with fluorosilane were synthesized by surface modification technology. The size, morphology and phase structure of as-prepared surface-modified LaF 3 nanoparticles were analyzed by means of X-ray diffraction and transmission electron microscopy. The tribological properties of surface-modified LaF 3 nanoparticles as additive of fluoro silicone oil were evaluated with a four-ball machine, and the morphology and elemental composition of worn steel surfaces were examined with a scanning electron microscope and an X-ray photoelectron spectroscope. Results show that 3-(heptafluoroisopropoxy)propyltriethoxysilane as the modifier is able to improve the dispersibility of LaF 3 nanoparticles in fluoro silicone oil. Moreover, when the optimum concentration, 0.08 wt.% of fluorosilane surface-modified LaF 3 is added into fluoro silicone oil, as-synthesized fluorosilane surface-modified LaF 3 nanoparticles exhibit excellent anti-wear as additive in fluoro silicone oil. The wear scar diameter under the optimum concentration is always smaller than that under the lubrication of fluoro silicone oil alone. Especially, when the load is 500 N, 600 N and 700 N, the wear scar diameter is reduced by 17%, 43% and 42%, respectively. In addition, during the friction process, LaF 3 nanoparticles are deposited on the rubbed steel surface to form LaF 3 deposition layer which functions jointly with the boundary lubricating film thereby resulting in improved tribological properties.

Improvement in oil resistance of room temperature-vulcanized polysiloxane rubber via blending with self-synthetic fluorosilicone

In this work, different contents of vinyl-terminated fluorosilicone oil (VFS oil) were blended with room temperature-vulcanized (RTV) polydimethylsiloxane (PDMS). Via rheological detection, the addition of VFS oil could increase the viscosities of VFS/PDMS/silicon dioxide (SiO2) blends, probably due to the interaction between incorporated fluorine atom and silanol on the surfaces of SiO2. The additional “structuring effect” was reduced by enhancing the shearing rate of the mixed gums containing VFS oil and the obvious shear-thinning property was helpful for enhancing the processability. The curing process and cross-linking degree test of VFS/PDMS/SiO2 blends suggested that the VFS oil could reduce the curing time and the induction time, but did not play a positive role in the cure depth using a platinum catalyst. Mechanical property tests showed that the VFS oil did not increase the tensile strength and elongation at break, and the hardness slightly decreased with increasing VFS oil content. The oil resistance property test showed that the oil resistance of the polysiloxane rubber was well improved by the incorporation of the VFS oil containing the functional group –CH2CH2CF3.

Tribological Properties of Gray Cast Iron/ AISI 52100 Steel Contacts when Lubricated with Fluorosilicone Oils as Additives

Abstract. Two fluorosilicone oils as additives were evaluated using an Optimol SRV reciprocating friction and wear tester by gray cast iron disc against AISI 52100 steel ball at 20 N and sliding speed of 0.20 m/s, respectively. The morphologies of worn surface of the disc were examined using a scanning electron microscope (SEM). In addition, the elemental compositions and chemical states of several typical elements on the worn surfaces of the gray cast iron discs were examined by means of X-ray photoelectron spectroscopy (XPS). Results indicate that PAO(Poly-alpha-olefin)+F-Si-E exhibite excellent tribological properties. This is partly attributed to material properties and tribological reaction between the lubricant and the sliding surface.

Emulsification experiments with dimethylsiloxane/phenylmethylsiloxane copolymer

We compared the emulsification tendency of dimethylsiloxane/phenylmethylsiloxane copolymer (DPC; 5%-phenylated, specific gravity 0.984) with that of silicone oil (dimethylsiloxane; SO, specific gravity 0.966) and fluorosilicone oil (methyl-3,3,3-trifluoropropylsiloxane; FSO, specific gravity 1.256), which are clinically used as an intraocular tamponade. After SO, DPC and FSO were placed in a glass container with an equal amount of albumin solution (1 mg/ml) or gamma-globulin solution (1 mg/ml), and shaken SO and DPC, with their specific gravities being closer to water, showed less emulsification than FSO. Following vitrectomy, DPC was injected into the rabbit vitreous cavity, but did not seem to show any severe histological damage. Highly-phenylated DPC, which is slightly heavier than water, may be useful to treat inferior retinal detachment in place of FSO.

Preparation, Characterization and Antifoaming Property of Fluorosilicone Oils with Fluoroalkyloxypropyl Group Substitution

AbstractThe current work has focused on the preparation and property of a novel fluorosilicone oil with polyfluoroalkyloxypropyl group substitution. Using fluoroalcohols as materials, three kinds of fluorosilicone oil, named [3-(2,2,2- trifluoroethyl-oxy)propyl]methylsilicone oil, [3-(2,2,3,3-tetrafluoropropyl-oxy)propyl] methylsilicone oil and [3-(2,2,3,3,4,4,5,5-octafluoropentyl-oxy)propyl]methyl silicone oil, were prepared via condensation, hydrosilylation, cyclization and ringopening polymerization. All the fluoroalkyl derivatives were characterized by NMR, FT-IR, MS and elemental analysis technique. The thermal stability of these fluoroalkyoxypropylmethylsilicone oils was identified to be excellent by thermogravimetric analysis. [3-(2,2,3,3,4,4,5,5-octafluoropentyl-oxy)propyl]methyl silicone oils with different viscosity were prepared by varying the amount of endblock reagent in the polymerization, and the antifoam property of these fluorosilicone oils was investigated. The result showed that the antifoam property of octafluorosilicone oil with higher viscosity was better than that with lower viscosity.

Recent advances in polymeric vitreous substitutes

The vitreous humor occupies two thirds of the volume of the eye and is the major component behind the lens. The human vitreous is a gelatinous substance predominantly composed of water (98–99%). Its functions include holding the retina in place and circulating metabolites throughout the eye. The vitreous liquifies with age, facilitating posterior vitreous detachment, which can lead to retinal tears, intravitreal hemorrhage or retinal detachment. Vitreous substitutes are needed to tamponade the retina or during vitrectomies for treatment of retinal detachments. Gases, perfluorocarbon liquids and silicone or fluorosilicone oils are currently used as vitreous substitutes; however, none of these substitutes can be used long term due to the short retention time of the gaseous substitutes, cell toxicity or other complications, such as glaucoma or cataracts. Vitreous substitutes, both experimental and clinical, will be reviewed, along with promising experimental artificial vitreous; polymeric hydrogels.

The Biocompatibility of Silicone, Fluorosilicone and Perfluorocarbon Liquids as Vitreous Tamponades

Purpose: To investigate the interactions occurring at the interface between some currently used vitreous tamponading substances and the ocular tissues, in an early follow-up after surgery. Methods: Adult albino rabbit eyes underwent vitrectomy and were injected intravitreally with silicone oils at 1,000 or 3,000 cSt, fluorosilicone oil and perfluorodecalin. Different morphological techniques (light microscopy, scanning and electron microscopy, immunohistochemistry) were applied. Results: All the tested materials, although non-toxic, penetrate the ocular tissues also at the anterior segment level, and in the long-term follow-up this can yield functional impairment. No massive inflammation has been detected in the zones in contact with the materials, but immunoglobulins and complement fractions are anyway present in the stroma of various tissues and around the droplets of emulsified materials, suggesting a local immune reaction. Conclusions: Data from this study confirmed that a permanent vitreous substitute, showing a perfect biocompatibility, still does not exist. The indication to remove the tamponading substance within 2 months after the surgery emerges from this investigation, confirming previous studies. Despite some negative features, silicone oil still appears the most biocompatible material for vitreous replacement.

Emulsification Tendency of Silicone-Phenylsilicone Copolymer

Purpose: We compared the emulsification tendency of silicone-phenylsilicone copolymer (DPC; 5%-phenylated, specific gravity 0.984) with that of silicone oil (SO; specific gravity 0.966) and fluorosilicone oil (FSO; specific gravity 1.256), all of which are used clinically as intraocular tamponades. Methods: We investigated the tendencies of emulsification in SO, FSO, and DPC. Each was placed in a separate glass container with equal amounts of albumin solution (1 mg/mL) or 1 γ-globulin solution (1 mg/mL) and shaken. We also investigated the toxicity of DPC in the rabbit eye. Following vitrectomy, we injected DPC into the vitreous cavity and assessed the retinal damage histologically. Results: The SO and DPC, because their specific gravities, are closer to water, tended to become less emulsified than did FSO. We found that DPC did not cause any severe histological damage in the rabbit retina. Conclusion: Highly phenylated DPC is slightly heavier than water and may be used instead of FSO to treat inferior retinal detachment.

HISTOPATHOLOGIC RETINAL CHANGES WITH INTRAVITREOUS FLUOROSILICONE OIL IN RABBIT EYES

Background: Fluorosilicone oil (FSiO, 1,000-10,000 centistokes), which has a higher density (1.29 g/cm3) than vitreous gel, is useful as an operative tool and a tamponade for the inferior retina during difficult retinal detachment surgery. The occurrence of histopathologic retinal changes after injection of FSiO into the vitreous cavity is controversial. Methods: Retinas obtained from 18 rabbits were evaluated histopathologically within 8 weeks of injection into the vitreous cavity of purified FSiO or balanced salt solution as control in phakic eyes. The histopathologic retinal changes caused by FSiO were compared with those of previously reported high-density hydrophobic vitreous substitutes, such as silicone-fluorosilicone copolymer oil (SiFO) and perfluorocarbon liquids. Results: By light and electron microscopy, all retinas injected with FSiO were the same as control retinas within 2 weeks of the injection, but the outer plexiform layer disappeared from the inferior retina 4 weeks after injection. The receptor cell nuclei migrated to the photoreceptor layer in the inferior retina 8 weeks after injection. However, no preretinal membrane, including foam cells, was found in any eye injected with FSiO. Conclusion: FSiO may be useful as a temporary vitreous substitute in difficult inferior retinal detachments. RETINA 20:532-536, 2000

Biodegradable PLGA microspheres loaded with ganciclovir for intraocular administration. Encapsulation technique, in vitro release profiles, and sterilization process.

The purpose of this work was to obtain a sterilized formulation consisting of biodegradable microspheres of poly (DL-lactide-co-glycolide) (PLGA) for intraocular sustained release of ganciclovir. Microspheres were prepared using a dispersion of ganciclovir in fluorosilicone oil (FSiO) that was further dispersed in an acetone solution of PLGA [50/50 and inherent viscosity 0.41 dl/g], and emulsified in silicone oil with a surfactant. Once prepared, the formulation was exposed with an effective gamma radiation dose of 2.5 megarads. The release rate data of ganciclovir from the sterilized and nonsterilized batches were compared using the similarity factor (f2). The dispersion of the drug in FSiO contributed to achieving a drug payload of up to 95% of the theoretical in the 300-500 microm microspheres. Ten mg released ganciclovir in vitro at 1.3 microg/h for the first 21 days, but decreased to approximately 0.2 microg/h from day 25 until the end of the release study (42 days). No significant differences in the amounts of encapsulated drug (alpha = 0.05) were observed between the sterilized and nonsterilized microspheres. Furthermore, dissolution profiles of formulations behaved similarly before and after gamma radiation exposure. The technique of microsphere preparation described resulted in high ganciclovir loading (95%) and prolonged drug release. The ganciclovir formulation behaved similarly before and after the sterilization process.

Additives for fluorosilicone oils at high temperature

Fluorosilicones are a class of synthetic lubricants which possess promising, intrinsic, thermal and viscometric properties. However, like all non-hydrocarbon-based lubricants, their use is limited by a shortage of soluble additives able to enhance the properties of the base fluid under extreme conditions. This paper describes a search for possible additives, soluble in fluorosilicones and able to inhibit oxidation and reduce wear at high temperatures. A number of such additives and additive combinations have been identified.

MRI and intraocular tamponade media

Thirteen patients who underwent surgery for retinal detachment and injection of intraocular tamponade media (silicone oil, fluorosilicone oil, or perfluorocarbon liquid) underwent magnetic resonance imaging (MRI), using spin-echo T1- and T2-weighted images. The ophthalmic tamponade media showed different signal intensity, according to their chemical structure. Unlike ophthalmoscopy or ultrasonography, MRI showed no oil-related artefact, making possible recognition of recurrent retinal detachment.

Intravitreal silicone and fluorosilicone oils: pathologic findings in rabbit eyes.

The effects of medical-grade intraocular silicone and commercial-grade fluorosilicone oils were studied in rabbit eyes. The experimental model consisted of lensectomized and vitrectomized eyes that did not undergo further treatment (Group 1), and three groups of lensectomized and vitrectomized eyes that were injected intravitreously 3 months earlier with medical-grade silicone oil of 1000 cs (Group 3), and 10,000 cs (Group 4). The silicone oil-injected eyes developed proliferative membranes. The fluorosilicone oil caused an intravitreous inflammatory reaction with vacuolated macrophages present around the oil that may have been due to the higher concentration of low-molecular-weight components found in the oil.

Combined silicone and fluorosilicone oil tamponade (double filling) in the management of complicated retinal detachment.

We evaluated the use of simultaneous double filling with polydimethylsiloxane (PDMS) and fluorosilicone (FSiO) in the repair of complicated retinal detachment in 12 selected cases. Initial retinal reattachment was achieved in all cases. Proliferative vitreoretinopathy (PVR) recurred in 10 patients (83%), 6 of which showed partial retinal detachment. Inferior and superior postoperative residual free spaces were abolished by this procedure, but a new residual fluid space was created, lying horizontally between the bubbles and expanding in a triangular shape nasally to the optic disk and temporally to the macula. Overall, 9 of 10 eyes with postoperative PVR had proliferation involving these areas. These findings support the concept that 'compartmentalization' is of major importance in determining postoperative cell proliferation.

Use of High-Density Vitreous Substitutes in the Removal of Posteriorly Dislocated Lenses or Intraocular Lenses

We successfully used high-density vitreous substitutes to remove four dislocated crystalline lenses and three dislocated intraocular lenses (IOLs) from the vitreous cavity. Fluorosilicone oil (300 cs) was used to remove the four lenses and one of the IOLs. Perfluorophenanthrene (Vitreon) was used to remove the other two dislocated IOLs. The dislocated lenses or IOLs were floated by the high-density vitreous substitutes and removed safely without damaging the retina; there were no intraoperative complications. Postoperative residual fluorosilicone oil droplets were found in one case.