Increasing Polyethylene Glycol Concentration Research Articles

In vitro screening of durum wheat against water-stress mediated through polyethylene glycol.

Three durum wheat (Triticum durum Desf.) genotypes with three levels of drought tolerance were screened in order to evaluate their response to water stress at callus induction and plant regeneration levels. Significant differences were observed among the genotypes, and polyethylene glycol (PEG) levels used, and their interactions were however, significant for all the studied characters. Increase in PEG concentration increased the time required for callus initiation and reduced the number of calli frequency of embryogenic structures and number of plants regenerated, showing the adverse effect of PEG on the somatic embryogenesis developmental., under in vitro conditions tested, and Djenah Khetifa was the most tolerant genotype, followed by Oued Zenati and Waha. This pattern was per their drought tolerance behavior under field conditions. Principal component analysis (PCA) showed that 95.56% of the total variation was explained by the first two principal components. Biplot analysis allowed the stress-tolerant genotype to be distinguished from the two less tolerant genotypes. Time required for callus initiation was strongly negatively correlated with all other studied traits. These traits can be recommended as suitable selection criteria for screening drought-tolerant genotypes. The selected cells and plants will provide a tool for determining the mechanisms involved in tolerance to water stress.

Triple-component nanocomposite films prepared using a casting method: Its potential in drug delivery

The purpose of this study was to fabricate a triple-component nanocomposite system consisting of chitosan, polyethylene glycol (PEG), and drug for assessing the application of chitosan–PEG nanocomposites in drug delivery and also to assess the effect of different molecular weights of PEG on nanocomposite characteristics. The casting/solvent evaporation method was used to prepare chitosan–PEG nanocomposite films incorporating piroxicam-β-cyclodextrin. In order to characterize the morphology and structure of nanocomposites, X-ray diffraction technique, scanning electron microscopy, thermogravimetric analysis, and Fourier transmission infrared spectroscopy were used. Drug content uniformity test, swelling studies, water content, erosion studies, dissolution studies, and anti-inflammatory activity were also performed. The permeation studies across rat skin were also performed on nanocomposite films using Franz diffusion cell. The release behavior of films was found to be sensitive to pH and ionic strength of release medium. The maximum swelling ratio and water content was found in HCl buffer pH 1.2 as compared to acetate buffer of pH 4.5 and phosphate buffer pH 7.4. The release rate constants obtained from kinetic modeling and flux values of ex vivo permeation studies showed that release of piroxicam-β-cyclodextrin increased with an increase in concentration of PEG. The formulation F10 containing 75% concentration of PEG showed the highest swelling ratio (3.42±0.02) in HCl buffer pH 1.2, water content (47.89±1.53%) in HCl buffer pH 1.2, maximum cumulative drug permeation through rat skin (2405.15±10.97 μg/cm2) in phosphate buffer pH 7.4, and in vitro drug release (35.51±0.26%) in sequential pH change mediums, and showed a significantly (p<0.0001) higher anti-inflammatory effect (0.4 cm). It can be concluded from the results that film composition had a particular impact on drug release properties. The different molecular weights of PEG have a strong influence on swelling, drug release, and permeation rate. The developed films can act as successful drug delivery approach for localized drug delivery through the skin.

Ionic liquid integrated polyethylene glycol (PEG)-based quasi-solid electrolyte for efficiency enhancement of dye-sensitized solar cell

We are presenting herein the effect of using three different cell electrolytes namely: (a) propylene carbonate containing 0.2 M LiI and 0.02 M I 2; (b) a polymer electrolyte, same as (a) having polyethylene glycol (PEG) as polymer matrix; and (c) polymer electrolyte same as (b) with added ionic liquids, 1, 2-dimethyl-3-propylimidazolium iodide or 1-ethyl-3-methylimidazolium iodide on the performance of TiO2-based dye-sensitized solar cells (DSSCs). Electrolytes were structurally characterized using FTIR spectra, and their thermal stability was studied through TGA in the temperature range of 30–600 °C. Fabricated cells with varied composition of the cell electrolyte were assessed for their electrical outputs (J SC, V OC, η etc.) and EIS characteristics. Ionic liquid imbibed polymer electrolyte demonstrated improved thermal stability and higher room temperature ionic conductivity of 4.48 mS cm−1. DSSC composed of the polymer electrolyte with 1-ethyl-3-methylimidazolium iodide has shown an open-circuit voltage V oc = 0.75 V, a short-circuit current density J sc = 3.61 mA/cm2, fill factor FF = 0.51, and overall conversion efficiency η = 1.6% under irradiance of 100 mW cm−2. The conversion efficiency was enhanced by 60% with added ionic liquid compared to DSSC employing PEG-based polymer electrolyte. An increase in charge-transfer resistance (R ct) with increasing PEG concentration in the cell electrolyte from 20 to 60% and decrease with the addition of ionic liquids were observed. The cell performance at elevated temperatures was assessed by determining the photocurrent–potential curves for the cells with different electrolytes at temperatures ranging from 30 to 60 °C. The temperature variation resulted in strong influence on J SC, but the effect over V OC was insignificant.

PEG-assisted hydrothermal synthesis of CoFe2O4 nanoparticles with enhanced selective adsorption properties for different dyes

Cobalt ferrite nanoparticles (CFO NPs) are synthesized by a facile and polyethylene glycol (PEG) assisted hydrothermal method. In the synthesis of cobalt ferrites, PEG is used as a surfactant. The formation of single-phase spinel structure in the samples is confirmed by XRD patterns. TEM images show that the addition of PEG results in the decrease in the size of the CFO NPs. When the amount of PEG is lower than 2.4g, the particle sizes decrease, then, further increasing the concentration of PEG in the solution, the particle sizes begin to increase, for much more PEG will cover onto the surface of the nanoparticles. Here, the existence of PEG on the surface of CFO NPs is confirmed from the characteristic bands of PEG in FTIR spectra. All the samples are ferromagnetic, and their saturation magnetization (Ms) decreases with the increase in PEG concentration. The as-synthesized samples show highly selective adsorption characteristics for organic dyes. Compared with methyl orange (MO) and methyl blue (MB) dyes, good adsorption performance of the PEG/CoFe2O4 nanocomposites for Congo red (CR) dye is presented. Moreover, the addition of PEG greatly enhances their adsorption capacity (qe) for CR. The corresponding adsorption behavior fits well with the pseudo-second-order kinetic model and the Langmuir model. And the adsorption mechanism is investigated. This study suggests that the as-prepared products can be regarded as an excellent selective adsorbent to remove dyes from the wastewater.

English

Thiamine or vitamin B 1 comprises a pyrimidine moiety and a thiazole moiety. Thiamine pyrophosphate (TPP), the active form of thiamine, acts as a cofactor for various major enzymes, for example, transketolase (TK), α-ketoglutarate dehydrogenase (KGDH) and pyruvate dehydrogenase (PDH). It is suggested that TPP plays another important role, which is protecting plants against abiotic and biotic stresses such as osmotic stress. In this study, the gene transcripts of first two enzymes in thiamine biosynthesis pathway, THIC and THI1/THI4 were identified and amplified from oil palm tissues. Primers were designed based on sequence comparison of the genes from Arabidopsis thaliana , Zea mays , Oryza sativa and Alnus glutinosa . Oil palm’s responses in terms of the expression profiles of these two thiamine biosynthesis genes to an osmotic stress inducer, polyethylene glycol (PEG) were examined. The level of gene transcripts was analyzed using reverse transcriptase polymerase chain reaction (RT-PCR) and both THIC and THI1/THI4 gene transcripts were successfully amplified. The levels of transcription were measured and the results showed that the expression of THIC gene transcripts showed an increase of up to 200% in 1% PEG treated plant as compared to non-treated plant while the expression of THI1/THI4 gene transcripts showed an increase of up to 100% in treated plant as compared to non-treated plant. However, increase in concentration of PEG showed decrease in amount of transcription level for both gene transcripts. The results support the suggestion that thiamine may play an important function in plant defense against stresses as these findings may lead to an overexpression of thiamine in general. Keywords: Thiamine, vitamin B1, osmotic stress, oil palm, gene expression

Germination Behavior of Wheat (Triticum Aestivum L.) as Influenced by Polyethylene Glycol (PEG)

Pre-sowing seed treated with Polyethylene Glycol (PEG) helps to enhance the germination behavior of seed. So, a lab experiment was conducted to find out the effect of various Polyethylene Glycol (PEG) concentrations on the germination behavior of wheat. Wheat seeds of BARI Gom 27 and BARI Gom 28 were pre-soaked in 0, 5, 10, 15 and 20% PEG solution and untreated seeds were served as control. Results revealed that seed priming enhanced germination percentage (GP), vigor index (VI) and germination index (GI) of wheat seed. The highest GP (95.55%), VI (201.00) and GI (43.73) were obtained from seeds of BARI Gom 27 pre-treated with 10% PEG solution compared to BARI Gom 28 (75.55%, 128.71 and 27.12 of GP, VI and GI, respectively) and then decreased gradually with increasing PEG concentration. Therefore, seed priming helps to enhance the germination behavior of wheat seed.

Poly (Ethylene Glycol) (PEG)-assisted shape-controlled synthesis of one-dimensional ZnO nanorods

One dimensional (1D) ZnO micro/nanorods were successfully synthesized through polyethylene glycol (PEG)-assisted wet chemical route. The interaction mechanism and the formation of ZnO micro/nanorods were elucidated and correlated with various analytical techniques. The PEG, tend to influence the structural growth and optical properties of ZnO. Crystalline hexagonal wurtzite phase of ZnO was confirmed by XRD patterns for all the samples. The crystallite size increased from 19 to 33nm as an increase in PEG concentration. The morphology of 1D ZnO nanostructures was studied by SEM, which showed the formation of sporadic growth of rod-shaped elongated particles. The elemental composition of ZnO was confirmed from EDX measurement. UV–vis results revealed that the PEG concentration affected the absorption edge of ZnO, shifted toward longer wavelength, and the optical band gap energy decreased from 3.25eV to 3.09eV. Strong band-edge emission at ∼400nm was observed in all samples, markedly shifted toward the ultraviolet region, with the increasing concentration of PEG. It was found that PEG can adjust the photoluminescence intensities; adequate PEG contributes to good crystallinity of ZnO nanorods. The results obtained through XRD and UV–vis spectroscopic analysis were interrelated with each other. The resulting 1D ZnO nanostructures are useful in dye sensitized solar cells as photo-anode.

Integration of poly(ethylene glycol) in N-fluorenylmethoxycarbonyl-l-tryptophan hydrogel influencing mechanical, thixotropic, and release properties.

Polyethylene glycol (PEG) is incorporated to improve the mechanical properties of N-fluorenylmethoxycarbonyl-l-tryptophan (FT) hydrogel producing the hybrid (FTP) gels designated as FTP1, FTP2.5, etc. having PEG concentrations of 0.05 and 0.125% (w/v), respectively. Both the FT and FTP1 gels exhibit fibrillar network morphology; the fibers of the FTP1 gel are thinner than those of the FT gel. FTP gels exhibit a magnificent improvement in mechanical properties, and the storage and complex moduli increase with a maximum of ∼2800% for the FTP2.5 gel. Creep recovery experiment exhibits a maximum strain recovery of 90% for the FTP1 gel. The thixotropic property is observed for both FT and FTP gels and the rate of recovery increases with increase of PEG concentration; the latter acts as a molecular adhesive to the gel fibers bringing back the network structure easily. Gelation of FT causes a 5-fold increase of fluorescence intensity due to molecular aggregation, and with increase of FT concentration the ratio of fluorescence intensities at 470 and 395 nm increases. Exploiting the thixotropic property of FT and FTP hybrid gels, doxorubicin (DOX) is successfully encapsulated, and tunable release of DOX using appropriate amount of PEG in the gel matrix under physiological conditions is observed.

Liposomal suspension of DSPC/cholesterol with polyethylene glycol: a study by light and X-ray scattering

To study the structure and dynamic properties of liposomal suspension with polyethylene glycol (PEG), we used small-angle X-ray scattering (SAXS) and dynamic light scattering techniques. Light scattering experiment revealed that increase in PEG concentration decreased diffusion coefficient of liposomal structure. Moreover, cholesterol addition contributed to reduction of collective diffusion coefficient in the presence of PEG polymer. The SAXS experiment showed that the size and interaction of the liposome nanoparticle increased with an increase in PEG and cholesterol concentration.

Effect of pH on Bovine Serum Albumin (BSA) Solution to Polysulfone-based Membrane

In this work, polysulfone (PSf) flat sheet membrane was prepared via phase inversion technique. The effects of polyethylene glycol (PEG) additive on membrane performance were observed and investigated. The membrane permeation was evaluated in terms of pure water flux (PWF) and solute rejection at different pHs (pH 3, pH 5, pH 7 and pH 9). Bovine serum albumin (BSA) solution was used to study the performance of the prepared membrane. Results showed that the increase of PEG concentration led to higher PWF. This is due to PEG role as a pore forming agent in casting solution. The PWF was found to increase up to 101.85 LMH at 5% PEG. However, the PWF decrease when the PEG concentration is increased up to 7% and 9%. Similarly, flux rate at different pH showed the same plot as PWF. At pH 9, the PWF is high compared to pH 3, pH 5 and pH 7. The BSA rejection data at pH 3 and pH 5 shows the high rejection compared to pH 7 and pH 9. No significant changes were observed when PEG concentration was increased. As a conclusion, the addition of PEG has improved the performance of membrane in terms of PWF at a certain percentage (with the highest was given at 5%) of PSf membrane. It is also evidenced that the % of BSA rejection increased with decreasing pH.

Influences of Molecular Weight and Content of Polyethylene Glycol on Morphology and Size of Nano-Bioactive Glass

Nano-bioactive glass (NBG) was prepared via sol-gel method and freeze-dried technique using polyethylene glycol (PEG) as templates. The influences of molecular weight and content of polyethylene glycol on the morphology and the size NBG particles were investigated. The optimal sintering temperature of NBG was determined by using thermal gravimetric (TG) and differential thermal analysis (DTA), and the NBG particles were characterized by Fourier-transformed infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and X-ray diffraction (XRD). The XRD pattern of NBG sintered at 650°C in air confirmed that the calcined glass existed in amorphous state. The results indicated that the PEG molecular weight and PEG content have obvious effects on the morphology and size of the NBG particles. The size of NBG particle prepared with PEG-200 was beyond 1μm and the aggregation was obvious. The size of obtained NBG particle with PEG-10000 was between 50 nm and 80 nm, with a hollow spherical shape; while the morphology of the NBG with PEG-20000 was needle-shaped, with an average width of 20 nm and length of 100 nm. The particle size of the NBG particles decreased with the increase of PEG concentration.

Electrochemical Studies of Hydroxyapatitie-Poly Ethylene Glycol Nanocomposite

Hydroxyapatite(HAp)-poly ethylene glycol (PEG) nanocomposites of varying composition for biomaterial applications have been synthesized. The HAp/PEG nanocomposite materials were characterized by XRD, FTIR, FESEM, and HRTEM. Hydroxyapatite (HAp) nanorod embedded composite was prepared using PEG as a matrix with different weight percentages (wt%). The results indicated that the size and crystallinity of HAp nanoparticles decreases with increase in PEG concentration in the composite. HRTEM confirms the presence of HAp nano rod crystals in PEG matrix. Cyclic voltammograms (CVs) were recorded to evaluate the electrocatalytic behaviors of the modified electrode towards the oxidation of 4-NP in the potential range of 0 to +1.0 V. A glassy carbon electrode was modified with HAp-PEG nanocomposite and characterized in terms of electrochemical oxidation of 4-nitrophenol (4-NP) and 2-nitrophenol (2-NP) via cyclic voltammetry. The catalytic reaction facilitates electron transfer between 4-NP and the modified electrode, as a result the electrochemical oxidation of 4-NP becomes easier. The reason for this is that the HAp-PEG 40 can act as a promoter to increase the rate of electron transfer, lower the overpotential of 4-NP and 2-NP at the bare electrode, and the anodic peak shifts less positive potential. Thus, it is clear that HAp-PEG 40 modified GCE can be successfully used for the determination of organic pollutant.

Solubility and Henry's law constant of sulfur dioxide in aqueous polyethylene glycol 300 solution at different temperatures and pressures

In this work, isothermal gas–liquid equilibrium (GLE) data are reported for the system of SO2+N2+polyethylene glycol (PEG) 300+water (H2O) at five different reaction temperatures (from 298.15 to 318.15K) and different pressures (from 110.34 to 142.03kPa) with SO2 partial pressures in the range of 0 to 180Pa. Measurements were carried out by a saturation method using a glass absorption apparatus, which was controlled at constant temperatures by a thermostatic circulation bath with a Beckmann thermometer. The GLE data were obtained with uncertainties within ±0.02K for temperature, ±0.1kPa for total pressures, and ±0.05 for SO2 concentration in the gas phase and ±0.003 for SO2 concentration in the liquid phase. The measurements showed that the solubility of dilute SO2 in the system of PEG (1)+water (2) increased the with increasing PEG concentration in the mass fraction range of w1=(0.50–1.00). The solubility of SO2 in the system of PEG (1)+water (2) presented an extreme minimum at the mass fraction of w1=0.50 of 152.3gm−3 when SO2 in the gas phase was designed at ySO2=5×10−4. The solubility of dilute SO2 in the system of PEG (1)+water (2) increased with decreasing PEG concentration in the mass fraction range of w1=(0.05–0.50). The solubility of SO2 in the system of PEG (1)+water (2) presented an extreme minimum at the mass fraction of w1=0.05 of 270.7gm−3 when SO2 in the gas phase was designated at ySO2=5×10−4. Henry's law constants were fitted with a dynamic system based on the GLE data. Using the solubility data, the partial molar thermodynamic functions of solution, enthalpy and entropy, were calculated. Conclusions drawn from this work may be used to provide important GLE data for the design and operation of the absorption and desorption processes of PEG solutions in flue gas desulfurization.

Synergistic effects of polyethylene glycol and ammonium polyphosphate on intumescent flame-retardant polypropylene

A novel flame-retardant system of isotactic polypropylene (iPP) is prepared using polyethylene glycol (PEG) and ammonium polyphosphate (APP). The flammability of iPP/PEG/APP composites containing 20 wt% APP improves with the increase of PEG concentration in the range of 3–15 wt%. The limit oxygen index (LOI) of iPP/PEG/APP composites reaches up to 30% with 15 wt% PEG concentration in the composites. At the same time, the mechanical properties of iPP/PEG/APP composites demonstrate that PEG can enhance toughness of iPP/APP composites. The results of cone calorimetry prove the synergistic effects of PEG and APP on intumescent flame-retardant iPP, and those of the thermogravimetric analysis(TGA) reveal that iPP/PEG/APP samples decompose faster than iPP/APP composites. Investigated by scanning electronic microscopy (SEM), the morphology and structures of residues generated during LOI tests confirm the formation of effective char layer, and that the improvement of the flame retardancy and the impact strength of the composites are thanks to the presence of PEG. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers

Crowding effect on helix-coil transition: Beyond entropic stabilization

We report circular dichroism measurements on the helix-coil transition of poly(L-glutamic acid) in solution with polyethylene glycol (PEG) as a crowding agent. The PEG solutions have been characterized by small angle neutron scattering and are well described by the picture of a network of mesh size ξ, usual for semi-dilute chains in good solvent. We show that the increase of PEG concentration stabilizes the helices and increases the transition temperature. But more unexpectedly, we also notice that the increase of concentration of crowding agent reduces the mean helix extent at the transition, or in other words reduces its cooperativity. This result cannot be taken into account for by an entropic stabilization mechanism. Comparing the mean length of helices at the transition and the mesh size of the PEG network, our results strongly suggest two regimes: helices shorter or longer than the mesh size.

Synthesis and preliminary characterization of polyethylene glycol (PEG)/hydroxyapatite (HAp) nanocomposite for biomedical applications

Currently, composite materials have gained momentum in the field of orthopedics and maxillofacial surgery. Among the composite materials, ceramic/polymer possesses significant advantages of high mechanical reliability and excellent biocompatibility for applications in load bearing areas. In this work, polyethylene glycol (PEG)/hydroxyapatite (HAp) nanocomposites of varying weight percentages were synthesized and characterized physical-chemically by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), 31P nuclear magnetic resonance (NMR), thermo gravimetric analysis (TGA), differential thermal analysis (DTA) and field emission-scanning electron microscopy (FE-SEM) and biologically by antimicrobial and anti-inflammatory assays to evaluate their potential use for biomedical applications. The results indicated that the size and crystallinity of HAp nanoparticles decrease with increase in PEG concentration in the composite. SEM confirmed the presence of HAp nanorod crystals in PEG matrix. The nano PEG-20/HAp demonstrated the highest antifungal and antibacterial activity and favorable inhibition of human cell hemolysis. The designed PEG/HAp nanocomposites constitute promising candidates for biomedical applications. Key words: Hydroxyapatite, nanocrystalline, nanocomposite, poly ethylene glycol.

Role of additives in electroless copper plating using hypophosphite as reducing agent

In electroless copper plating baths using hypophosphite as the reducing agent, nickel ions was used to catalyze hypophosphite oxidation. However, the color of the copper deposits was dark or brown and the electrical resistivity was much higher than that obtained from formaldehyde baths. Polyethylene glycol (PEG) and K4Fe(CN)6 were used to improve the microstructure and properties of copper deposits obtained from electroless copper plating bath using hypophosphite as the reducing agent. The effects of PEG concentration on the deposition rate, the microstructure, morphology and electrical resistivity of the copper deposits, and the electrochemical reactions of hypophosphite (oxidation) and cupric ion (reduction) were investigated. The traces of hydrogen escaping from the deposits surface disappeared and the color of the copper deposits changed from dark-brown to dark red when the PEG concentration was 1.67×10−5M or more. The deposition rate increased and the electrical resistivity of the copper deposits decreased slightly with the addition of PEG to the plating solution. The electrical resistivity of copper deposits decreased to 2.85μΩ cm with 1.67×10−5M PEG and 4.70×10−6M K4Fe(CN)6 in the bath. Larger grain size and higher (220) plane orientation were obtained with the increase of PEG concentration in the bath. The electrochemical current–voltage results showed that PEG accelerated the catalytic oxidation of hypophosphite at active nickel sites and had little effect on the reduction reaction of cupric ions on the deposit surface by adsorption on the electrode.

Effect of polyethylene glycol on luminescence properties and morphologies of BaAl 2 Si 2 O 8 :Eu 2+ phosphors

Eu 2+ -doped BaAl 2 Si 2 O 8 blue phosphor was prepared by the one-step calcination process of the chemical coprecipitation method. The phase structure, luminescence properties and morphologies of the samples were investigated by X-ray powder diffraction, fluorescence spectrophotometer and scanning electron microscopy, respectively. A tiny amount of BaAl 2 O 4 phase was detected after adding polyethylene glycol (PEG) in precursor solution. The emission intensity increased with increasing PEG concentration at the beginning, and then decreased owing to the adverse enhancement of impurity phase and concentration quenching of Eu 2+ ions resulted from addition of PEG. The emission peak position of the sample with 4 wt% PEG has a blue-shift compared with the other concentrations, which is attributed to Eu 2+ emission mainly influenced by the Nephelanxetic effect. The morphology of particles changed from platelet or block to subglobular with increasing PEG concentration because PEG changed a nucleation process of crystal and gave rise to steric hindrance effect.

Molecular-Crowding-Induced Clustering of DNA-Wrapped Carbon Nanotubes for Facile Length Fractionation

Emerging applications require single-wall carbon nanotubes (SWCNTs) of well-defined length. Yet the use of length-defined SWCNTs is limited, in part due to the lack of an easily accessible materials preparation method. Here, we present a new strategy for SWCNT length fractionation based on molecular crowding induced cluster formation. We show that the addition of polyethylene glycol (PEG) as a crowding agent into DNA-wrapped SWCNT dispersion leads to the formation of reversible, nematic, and rodlike microclusters, which can be collected by gentle centrifugation. Since shorter SWCNTs form clusters at higher polyethylene glycol concentration, gradual increase in PEG concentration results in length fractionated SWCNTs. Using atomic force microscopy (AFM) we show that fractions with average lengths of 60-500 nm and standard deviations of 30-40% can be obtained. The concept of molecular-crowding-based fractionation should be applicable to other nanoparticle dispersions.

Effect of polymer on the elasticity of surfactant membranes: A light scattering study

We have performed a dynamic light-scattering (DLS) investigation of the effect of a water-soluble polymer, polyethylene glycol (PEG), on the bending elastic modulus κ of surfactant membranes. The polymer, in concentrations ranging from 0 to 8 g/L (0 to 0.4 mM), was incorporated into the solvent of sponge phases of the sodium dodecyl sulfate (SDS)-hexanol-brine system. PEG adsorbs into the SDS membranes. The correlation functions of the polymer-doped sponge phases displayed a stretched-exponential decay, appropriately described by the Zilman-Granek (Z-G) theory for fluctuating membranes. The dynamics of the surfactant bilayers was slowed down by the addition of the polymer: Increasing PEG concentrations increase the DLS relaxation times. From the Z-G model we extracted the membrane-bending elastic modulus, as a function of polymer concentration, C(PEG) = κ increases with C(PEG), a behavior opposite to that expected from available models for the interaction between fluid membranes and adsorbing polymers. Our results suggest that the polymer penetrates to some extent the surfactant bilayers.