Silicone Surfactants Research Articles

친환경 실리콘계 드라이클리닝 용제(Decamethylcyclopentasiloxane, D5)의 모직물 세척성 향상을 위한 드라이클리닝세제용 계면활성제 연구

Detergency and soil redeposition of wool fabric in drycleaning solvents, i.e. petroleum solvent, perchloroethylene (PCE), decamethylcyclopentasiloxane(D5), with commercial detergents were studied. The detergency of wool soiled cloth in drycleaning solvents without detergents were the order of PCE > petroleum solvent > D5. When commercial detergents were added to the system, the detergency were greatly improved. When 1.0% water was added to solvents/commercial detergents system, the detergency of petroleum solvent and PCE improved whereas that of D5 decreased. The soil redeposition prevention effects of solvents were the same order of detergency, i.e. PCE > petroleum solvent > D5. When commercial detergents were added to the system, the soil redeposition changed depending on solvents and detergents. The soil redeposition in D5 became higher with a commercial detergent, therefore it is important to develop appropriate detergents for D5. Three silicone surfactants were tested for detergency and soil redeposition in D5 to find candidate surfactants for drycleaning detergent formulations. Silicone surfactant PEG/PPG-19/19 Dimethicone was found to be the best surfactant for D5 drycleaning detergents.

Dispersing Carbon Nanotubes in Aqueous Solutions of Trisiloxane‐Based Surfactants Modified by Ethoxy and Propoxy Groups

AbstractSilicone surfactants favor spreading at interfaces and siloxane has strong interaction with carbon nanotubes (CNT), thus silicone surfactant may be a good dispersant of CNT. Here, four silicone surfactants (named S1E19, S2E38, S2E16 and S1E16P8) were used to disperse CNT in aqueous solutions. The effects of surfactant structure and concentration on the ability at dispersing CNT were considered. All of the four silicone surfactants can disperse CNT in aqueous solution and the sample with 1,000 mg L−1 S1E16P8 was the best one. The hydrophilic group polyoxyethylene (PEO) and the hydrophobic groups siloxane and polypropylene (PPO) are crucial factors in the ability of dispersing CNT. S2E38 with more ethylene oxide (EO) groups has a stronger ability to disperse CNT than S2E16. The dispersion system provided by S1E19 which contains fewer siloxane and EO groups is relatively unstable and disperses less CNT. These experimental results are explained by molecular dynamics simulation. S2E38 compared with S1E19 and S2E16 has stronger interactions with CNT. The interaction energy of CNT with S1E16P8 which has a PPO moiety but fewer siloxane groups is close to that of S2E16. Furthermore, it can be concluded that these four surfactants are adsorbed on CNT mainly by van der Waals forces and the Si–O–Si chain of silicon surfactant was flexible due to the long Si–C bond and it could easily wrap onto the surface of CNT through hydrophobic and other intermolecular interactions. The hydrophilic part of PEO helped the CNT dispersed in the aqueous solution and prevented CNT from aggregating in water through steric stabilization.

Nonelectrolyte-Induced Micellar Shape Changes in Aqueous Solutions of Silicone Surfactants

Dynamic light scattering, cloud point (CP), and surface tension studies have been carried out to examine the influence of six (including two acetates, two alkoxyethanols, and two sugars) nonelectrolyte additives on two silicone surfactants based on poly (dimethyl siloxane)—graft—polyethers in aqueous solutions. The results indicate that the presence of alkoxyethanols induced the oblate ellipsoidal to spherical micellar transition, while sugars increase the size of the ellipsoidal micelles. The effect of cosolvent or additives on critical micelle concentration (CMC) and CP is discussed on the basis of water structure making and breaking effect. The thermodynamic and surface active parameters were calculated from the surface tension isotherm curves.

Synergization of silicone with developed crosslinking to soy-based polyurethane foam matrix

Flexible polyurethane foam obtained from reaction of soybased polyol with TDI:MDI (80:20), and surfactant. The goal of this research is to determine the synergization effect of silicone with low molecular alcohols; methanol and ethylene glycol (EG) in soy-polyurethane formula on holding moisture of foams to density, foam solutions capacity, and cellular morphology. The optimized of polyol was achieved by ratio of epoxide/methanol 1:6 (mol/mol), and epoxide/EG 1:3 (mol/mol). It was found silicone surfactant can minimize solution absorbency in polyurethane foam matrix.

Synthesis, Characterization and Textural Analysis of Functionalized Mesoporous Silica Using Sodium Silicate as Precursor and Silicone Surfactant as Template

Three mesoporous silica with different functional group were prepared by one-step synthesis based on the simultaneous hydrolysis and condensation of sodium silicate with organo - silane in the presence of template surfactant polydimethylsiloxane - polyethyleneoxide (PDMS - PEO). The prepared materials were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), atomic force microscopy (AFM) and nitrogen adsorption/desorption experiments. The results indicate that the preparation of methyl and phenyl functionalized silica were successful and the mass of methyl and phenyl groups bonded to the silica structure are 15, 38 mmol per gram silica. The average diameter of the silica particles are 103.51, 167.25 , and 86.41 nm while the average pore diameter are 6.7, 16.4, and 2.7 nm for unfunctionalized, methyl, and phenyl functionalized silica respectively.

Effects of Silicone Surfactant on the Water Absorption and Surface Morphology of Rigid Palm Oil-Based Polyurethane Foam

Polyurethane (PU) foams are widely used today in automotive and as insulation system. Due to environmental issues, efforts have been made to replace petrochemical polyol with natural-based polyol in PU foam production, without sacrificing any properties. This study aims to produce palm oil-based PU rigid foam for non-load bearing applications such as wall panel or insulation for buildings. Two parameters studied were percentage of water uptake and surface foam morphology. Palm oil-based polyol (POP) was reacted with polymeric 4,4-diphenylmethane diisocyanate (p-MDI) at 1:1 NCO:OH ratio. Water was used as blowing agent and silicone surfactant was added to produce stable rigid PU foam. The content of silicone surfactant was varied at 2 and 3 part by weight (pbw). The percentage of water uptake increased slightly with increasing surfactant contents due to siloxane portion of the surfactants, is thought able to reduce the surface tension of the cell, thus absorbing more water than 2 pbw surfactant content. The findings were supported with micrographs of scanning electron microscope (SEM) that showed a larger cell window area and thicker strut.

Synthesis, Characterization and Textural Analysis of Functionalized Mesoporous Silica Using Sodium Silicate as Precursor and Silicone Surfactant as Template

Three mesoporous silica with different functional group were prepared by one-step synthesis based on the simultaneous hydrolysis and condensation of sodium silicate with organo - silane in the presence of template surfactant polydimethylsiloxane - polyethyleneoxide (PDMS - PEO). The prepared materials were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), atomic force microscopy (AFM) and nitrogen adsorption/desorption experiments. The results indicate that the preparation of methyl and phenyl functionalized silica were successful and the mass of methyl and phenyl groups bonded to the silica structure are 15, 38 mmol per gram silica. The average diameter of the silica particles are 103.51, 167.25 , and 86.41 nm while the average pore diameter are 6.7, 16.4, and 2.7 nm for unfunctionalized, methyl, and phenyl functionalized silica respectively.

Development and evaluation of oil in water nanoemulsions based on polyether silicone as demulsifier and antifoam agents for petroleum

ABSTRACTOil in water (o/w) nanoemulsions were synthesized in order to be evaluated as an alternative to petroleum emulsions destabilization processes and inhibition of foam formed in the crude oil. The nanoemulsions were prepared by the high energy method through High Pressure Homogenizer (HPH), utilizing poly(propylene glycol) (PPG) and xylene solvent as oil phase and different polarity polyether silicone surfactants samples. These nanoemulsions were evaluated in respect to their efficiency in the petroleum demulsification process. The results of these tests showed that nanoemulsions performance on the destabilization of petroleum emulsions is influenced by the utilized surfactant's polarity. The nanoemulsions and pure samples of PPG and xylene solvent were evaluated concerning capacity of formed foam inhibition in petroleum (antifoam test), and the results showed no significant influence of samples on foam stability. Petroleum/saline water added interfacial tension measurements, added or not the nanoemulsions were executed and showed that the additives adsorption in the interface is related to the surfactant's polarity and nanoemulsion drop size. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40889.

Development of Rigid Biocomposite Polyurethane Foam for Load Bearing Application

Polyurethane (PU) foams are widely used today in automotive and as insulation system. Due to environmental issues, efforts have been made to replace petrochemical polyol with natural-based polyol in PU foam production, without sacrificing any properties. This study aims as to produce palm oil-based polyurethane composite foam for load bearing purposes. Palm oil-based polyol (POP) was reacted with polymeric 4,4-diphenylmethane diisocyanate (p-MDI) with water as blowing agent and silicone surfactant to produce rigid PU foams. The foams obtained were varied by NCO:OH ratios and water content and characterized for their morphology and compressive strength. Scanning electron micrographs (SEM) indicated the cells within the obtained foams are closed cells. Compressive strength of obtained foams shows considerable improvement but only up to NCO:OH ratio of 1:1.35.

The effect of silicone hydrogel contact lens composition on dexamethasone release

The relationship between the delivery of dexamethasone and the composition of silicone hydrogel materials was investigated. Two hydrophilic monomers (2-hydroxyethyl methacrylate or N,N-dimethylacrylamide), a siloxy methacrylate-based monomer (1-(Bis(trimethylsiloxy)methylsilyl)propoxy-3-metacryloxy-2-propanol, a polysiloxane (monomethacryloxypropyl-terminated polydimethylsiloxane) and a polymerizable silicone surfactant (Silmer ACR A008-UP) were used to synthesize silicone hydrogels of variable composition. The materials properties, such as surface wettability and equilibrium water content, were highly dependent on polymer composition. All dexamethasone-loaded hydrogels showed uptake that was driven primarily by sorption to the polymer phase. Furthermore, a positive correlation between loading mass and equilibrium water content was established. The duration of drug release from the hydrogels ranged from one to greater than two weeks depending on the monomer composition and relative contribution of hydrophilic and hydrophobic monomers. Higuchi model rate constants for the release showed strong correlation with the equilibrium water content, signifying that the release is likely controlled by aqueous phase diffusion.

In vitro studies on release and skin permeation of nonivamide from novel oil-in-oil-emulsions

The purpose of this study was to develop oil-in-oil-emulsions that facilitate long-term treatment for chronic pruritus with capsaicinoids. To this end, oil-in-oil-emulsions, which comprised polydimethyl siloxanes, silicone surfactant and castor oil, were examined. We used nonivamide, a synthetic analogue of capsaicin as the active pharmaceutical ingredient. It was incorporated into castor oil that formed the dispersed phase of the emulsion. We evaluated the influence of formulation variables (nonivamide content, phase volume ratio and viscosity of the silicone oil) on the in vitro release and the permeation of nonivamide. Permeation was found to be controlled by the nonivamide concentration in the dispersed phase and the phase volume ratio. Oil-in-oil-emulsions were found to produce constant permeation rates over a period of 10h. They are thus superior to conventional semisolid formulations as application intervals may be extended.

Facile Functionalization of PDMS Elastomer Surfaces Using Thiol–Ene Click Chemistry

A variety of methods have been developed for polydimethylsiloxane (PDMS) elastomer surface functionalization, particularly for the improvement of hydrophilicity. However, in addition to difficulties in avoiding undesired physical changes to the modified surface, including surface cracking, "hydrophobic recovery" frequently leads hydrophilically modified surfaces to completely return over time to their hydrophobic nature, with accompanying loss of accessible functional groups. Thiol-ene chemistry provides a mild and robust technology for synthetic elaboration. We demonstrate the introduction of thiol groups onto the PDMS surface via base-catalyzed equilibration of MTS ((MeO)3Si(CH2)3SH). Thiols in the product elastomer were shown to be located primarily at the air interface using EDX, XPS, and fluorescence labeling initially, and after extended periods of time: total thiol concentrations at the surface and in the bulk were established by complementary chemical titrations with DTDP (4,4'-dithiodipyridine) and iodine titrations in different solvents. The surface density of thiols was readily controlled by reaction conditions: the rate of hydrophobic recovery, which led to incomplete loss of accessible functional groups, was determined. Thiol-ene click chemistry was then used to introduce a variety of hydrophilic moieties onto the surface including a silicone surfactant and maleic anhydride, respectively. In the latter case, molecular functionalization with both small (fluorescent labels) and polymeric nucleophiles (poly(ethylene glycol), chitosan) could be subsequently induced by simple ring-opening nucleophilic attack leading to permanently functional surfaces.

Silicone surfactant templating for mesoporous silica@carbon complex

Mesoporous silica@carbon complex (MSC) with ordered two dimensional (p6mm) arranged meso-channels were synthesized using resol precursors under the direction of commercially available silicone surfactant DOW CORNING® Q4-3667 FLUID (Q4-3667), which acted not only as effective template, but also as silica source. The as-made mesoporous material was prepared via hydrothermal procedure. After stepwise curing and further carbonization, the phenolic resins were converted to mesoporous carbon, and the well-arranged mesochannels were filled with nano-sized silica converted by the polydimethylsiloxane (PDMS) block of Q4-3667. The MSC exhibited improved electrochemical performance as lithium-ion intercalating material than its corresponding mesoporous carbon and complex with mixed silica–carbon frameworks.

Mixed Micelles of Trisiloxane Based Silicone and Hydrocarbon Surfactants Systems in Aqueous Media: Dilute Aqueous Solution Phase Diagrams, Surface Tension Isotherms, Dilute Solution Viscosities, Critical Micelle Concentrations and Application of Regular Solution Theory

AbstractMixtures of trisiloxane type nonionic silicone surfactant (SS) with sodium dodecylsulfate, tetradecyltrimethylammonium bromide or tert‐octylphenol ethoxylated with 9.5 ethylene oxide groups were studied in water at 30 °C by dilute aqueous solution phase diagrams, surface tension and dilute solution viscosity methods. The cloud points for the silicone surfactant aqueous solutions increased upon addition of hydrocarbon surfactants indicating the formation of hydrophilic complexes in mixture solutions. The scrutiny of the surface tension isotherms plotted as a function of SS concentration revealed that competitive adsorption effects are the characteristic features in these mixtures depending upon the SS concentration. Otherwise the isotherms exhibited two break points and the difference of concentration between the two break points increased with the increase in SS concentration indicating the cooperative nature of interactions. The micellar mole fractions of individual surfactants were determined by Rublingh's regular solution theory; interaction parameters and activity coefficients were evaluated and interpreted in terms of synergistic type interactions in these mixtures. The surface active parameters in mixture solutions were estimated and their analysis shows that the molecular species in the mixture solutions have a preferential tendency for adsorption at the air/water interface than in association form in the bulk solution. The effect of hydrocarbon surfactants on the intrinsic viscosity of SS micelles was monitored and related to the enhanced hydration in mixed micelles.

Effect of hydrophobic chains on the aggregation behavior of cationic silicone surfactants in aqueous solution

Three cationic silicone surfactants, (2-hydroxyethyl)-N,N-dimethyl-3-[tri-(trimethylsiloxy)]silylpropylammonium chloride (Si4ACl), (2-hydroxyethyl)-N,N-dimethyl-3-[bis(trimethylsiloxy)methyl]silylpropylammonium chloride (Si3ACl), and (2-hydroxyethyl)-N,N-dimethyl-3-[bis(trimethylsilylmethyl)methyl]silylpropyl-ammonium chloride (Si3C2ACl), with the same headgroups and different hydrophobic groups were synthesized. Their aggregation behavior in aqueous solution was investigated by surface tension and electrical conductivity. The results show that all the three cationic silicone surfactants perform admirable surface activity. Because of the effect of the hydrophobic groups, the critical micelle concentration values increase following the order Si3C2ACl < Si4ACl < Si3ACl, and Si3C2ACl packs more compactly at the air/water interface compared with Si4ACl and Si3ACl. Electrical conductivity studies show that all the three cationic silicone surfactants have low degree of counterion binding. Thermodynamic parameters ( $$ \varDelta\;H_m^0 $$ , $$ \varDelta S_m^0 $$ , and $$ \varDelta G_m^0 $$ ) of micellization derived from electrical conductivities indicate that the micellization for both Si3C2AC and Si3ACl in aqueous solution is enthalpy-driven, and that for the Si4ACl is entropy-driven. For the heat capacities, $$ \varDelta\;c_{m,p}^0 $$ , values are positive for Si4ACl, indicating that there is an attractive interaction between the nitrogen atom of one surfactant molecule and the oxygen atom of another surfactant molecule for Si4ACl.

Silicone surfactant templated mesoporous silica

Tailoring the wall thickness and organo-functionalization are two important issues in the design and application of mesoporous materials. Herein we report a novel strategy to deal with such two issues simultaneously by using a commercially available silicone surfactant, an ABA-type triblock copolymer poly(ethylene oxide)-block-polydimethylsiloxane-block-poly(ethylene oxide) (PEO14-b-PDMS13-b-PEO14). The silicone surfactant serves as the template for directing meso-structures, the source of functional groups for surface modification, and the silica source for strengthening the wall of mesochannels. Meanwhile, 1,3,5-trimethyl benzene (TMB) was employed as the pore-swelling-agent. The mesoporous silica materials with thick walls and/or hydrophobic dimethylsiloxane functionalized pores were achieved by calcination and extraction, respectively.

Layer-By-Layer Assembly of Complex Membranes

Reconstituting complex biological macromolecular and supramolecular structure and function from simple chemical starting materials is the central goal of bottom-up synthetic biology. Phospholipid bilayer membranes, which represent a critically important class of such structures, are central to the study of signal transduction pathways, membrane transport and remodelling, yet controlled assembly of membranes remains more art than science. To address this challenge we developed layer-by-layer (LbL) membrane assembly, the sequential deposition of amphiphile monolayers on microfluidic droplet templates. We have demonstrated LbL assembly of asymmetric, double- and multi-lamellar membranes of defined phospholipid composition and structurally probed these constructs by confocal fluorescence imaging of dye-labeled lipids. Parallel measurement of protein nanopore-mediated transport revealed concerted pore insertion and leakage over multiple vesicles (n > 20). We now demonstrate the amphiphile substrate scope of the technique through assembly and probing of vesicles composed entirely of non-ionic silicone or perfluorous surfactant as well as minimal phospholipids mixtures that mimic both the composition and asymmetry of prokaryotic and eukaryotic plasma membranes. Finally, we demonstrate high-resolution electron microscopy imaging-based validation of the membranes using in situ photo-polymerization, fixing, and membrane staining. LbL assemby provides an extensible and systematic route to natural and synthetic membrane bilayers with diverse chemical configurations in a device architecture that enables structure-function studies of unparalleled reproducibility and control.

Porous polyurethane composites based on bio-components

The rigid polyurethane (PUR) composites with an apparent density of ca. 300 kg/m3 were prepared using 4,4-diphenylmethane di-isocyanate, polyether polyols, an amine catalyst, silicone surfactant and water as a chemical blowing agent. This reference petrochemical formulation was modified with renewable components such as rapeseed oil-based polyols and flax fibers. The effects of the different contents of the two types of the bio-polyols and flax fibers on the mechanical and thermal properties, dimensional stability and water absorption of foamed PUR composites were investigated. The modification showed that the incorporation of bio-components may improve mechanical and thermal properties of final products.

Multifunctional amphiphilic siloxane architectures using sequential, metal‐free click ligations

AbstractPolysiloxanes or silicones are a class of macromolecules widely used in commerce because of their exceptional properties. Their derivatization leads to functional silicones with added value and properties, such as surfactants and liquid crystals, among many others. However, most silicone surfactants are monofunctional, owing to the synthetic challenges associated with the introduction of multiple functional groups onto the hydrolytically sensitive siloxane backbone. Thus, general routes to surface active silicones with multiple and different functional groups are not available. Herein, a synthetic strategy is reported that permits sequential derivatization of silicones with hydrophiles including oligo(ethylene oxides), carboxylic acids, and bromoalkylesters using a simple metal‐free Click reaction: the process benefits from mild conditions, extremely high yields and does not generate any by‐products, allowing the facile preparation of di‐ and trifunctional silicones that could not be readily obtained using traditional methods. The products exhibit amphiphilic characteristics as demonstrated through interfacial tension measurements that yielded the critical aggregation concentration of selected compounds. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013

Determination of glucocorticoids using cosurfactants ultrasonic-thermostatic-assisted cloud point extraction followed by high performance liquid chromatography

A novel approach, cosurfactants ultrasonic-thermostatic-assisted cloud point extraction (CUS-CPE) combined with high performance liquid chromatography and ultraviolet detection (HPLC-UV) is developed for the analysis of glucocorticoids (beclometasone dipropionate (BD), hydrocortisone butyrate (HB) and nandrolone phenylpropionate (NPP)) in human urine samples. In this study, four different cloud point extraction (CPE) systems are discussed, including DC-193-nonanoic acid, DC-193-sodium sulfate, DC-193-lauric acid and the classic Triton X-100 sulfate systems. Among them, DC-193-sodium sulfate and the classic Triton X-100 sulfate systems has been studied in the past few years. Comparing with the first two systems, DC-193-nonanoic acid system had a lower cloud point (CP), little UV absorbance and it is less damaging to the column of three glucocorticoids in same surfactant concentration which was required for application as a pre-concentration process prior to HPLC. Phase diagrams were used to study the cavitation and mass transfer behaviors of the two phases on micelles of polyether type organic silicon surfactant, PEG-12 dimethicone (DC-193).The volumes of surfactant-rich phase obtained were very small (the enrichment factor (EF) was 35), which was much smaller and had a quick phase separating speed than that of Triton X-100 in the same surfactant concentration. Linearity was investigated from 1 to 350 ng mL-1. The limits of detection (LOD) thus estimated were 1.29 for BD, 2.67 for HB and 3.33 ng mL-1 for NPP, respectively. In proposed CPE step is rapid and effective to obtain recovery of three glucocorticoids higher than 85%, which is similar or better than literature reported data. The method was shown to be selective, linear, precise and reproducible and successfully applied for the analysis of glucocorticoids in human urine samples.