Free Energy Parameters Research Articles

Permeability and selectivity of acid gases in supported conventional and novel imidazolium-based ionic liquid membranes

The novel imidazolium salts based on bis(2-ethylhexyl) sulfosuccinate anion have been developed as ionic liquids (ILs) which can potentially be used as absorbents of acid gases. The transport of CO2, H2S, CH4 and N2 in a series of supported ionic liquid membranes (SILMs) with immobilized conventional (bmim[PF6], bmim[BF4], bmim[Tf2N]) and novel ILs was investigated. The supported ionic liquid membrane containing 1-butyl-3-methylimidazolium bis(2-ethylhexyl) sulfosuccinate (bmim[doc]) yielded a very high H2S solubility and, hence, H2S/N2 selectivity equal to 65. However, the permeability of acid gases through such a membrane had relatively low values varying in a range of 100–200 Barrer, whereas permeability for SILMs impregnated by conventional ILs achieved 565 Barrer. The most effective separation of CO2 was observed for SILMs impregnated by bmim[BF4] predominantly owing to solubility component of permeability. In order to estimate the stability of SILMs, the polymeric support surface properties such as free surface energy, surface topology and roughness parameters were evaluated. Analysis of experimental data revealed that among the tested ILs, bmim[BF4] immobilized in porous polymeric support was more resistant to losses and determined the higher stability of membranes.

Surface properties and morphology of mixed POSS-DPPC monolayers at the air/water interface

From the point of view of the possible medical applications of POSS (polyhedral oligomeric silsesquioxanes), it is crucial to analyse interactions occurring between POSS and model biological membrane at molecular level. Knowledge of the interaction between POSS and DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) allows prediction of the impact of POSS contained in biomaterials or cosmetics on a living organism. In the study presented, the surface properties and morphology of Langmuir monolayers formed by mixtures of POSS and the phospholipid (DPPC) at the air/water surface are examined. We selected two POSS derivatives, with completely different chemical structure of substituents attached to the corner of the silicon open cage, which allowed the analysis of the impact of the character of organic moieties (strongly hydrophobic or clearly hydrophilic) on the order of POSS molecules and their tendency to form self–aggregates at the air/water surface. POSS derivatives significantly changed the profile of the π–A isotherms obtained for DPPC but in different ways. On the basis of the regular solution theory, the miscibility and stability of the two components in the monolayer were analysed in terms of compression modulus (Cs−1), excess Gibbs free energy (ΔGexc), activity coefficients (γ) and interaction parameter (ξ). The results obtained indicate the existence of two different interaction mechanisms between DPPC and POSS which depend on the chemical character of moieties present in POSS molecules.

Efficient removal mechanism for antibiotic resistance genes from aquatic environments by graphene oxide nanosheet

In this study, removal efficiency and mechanism of four typical ARGs with two different molecular structures (i.e., cyclic (c)- and double-stranded (ds)-ARGs) by graphene oxide (GO) nanosheet were systematically investigated. The average removal of four ARGs was as high as 3.11 logs toward c-ARGs and 2.88 logs toward ds-ARGs at 300μg/mL GO solution. The data of adsorption were fitted well with Freundlich isotherm and pseudo-second-order kinetic model. The apparent adsorption equilibrium can be obtained within 15mins for both c-ARGs and ds-ARGs, indicating the effective removal by GO. The free-energy parameters demonstrated that the removal processes were exothermic and spontaneous. The structural differences of genetic molecular structures can be responsible for the removal discrepancy. Moreover, several removal factors containing initial ARGs concentration, pH and ion species were also investigated. The results of Raman spectra, Diffuse Reflectance Infrared Fourier Transform spectroscopy (DRIFTs) and electrochemical analysis indicated that the adsorption of ARGs by GO was mainly attributed to the oxygen containing groups and π-bonding system of GO nanosheet, which resulted in chemical binding with aromatic nucleic acid and strongly π-stacking interactions. Furthermore, a detailed verification test of real water samples was conducted and 80% of the ARGs can be removed from a natural water sample. As a result, it would be great potential to apply GO nanosheet as a novel adsorbent for effective treatment of ARG-contaminated waters.

Blind tests of RNA nearest-neighbor energy prediction

The predictive modeling and design of biologically active RNA molecules requires understanding the energetic balance among their basic components. Rapid developments in computer simulation promise increasingly accurate recovery of RNA's nearest-neighbor (NN) free-energy parameters, but these methods have not been tested in predictive trials or on nonstandard nucleotides. Here, we present, to our knowledge, the first such tests through a RECCES-Rosetta (reweighting of energy-function collection with conformational ensemble sampling in Rosetta) framework that rigorously models conformational entropy, predicts previously unmeasured NN parameters, and estimates these values' systematic uncertainties. RECCES-Rosetta recovers the 10 NN parameters for Watson-Crick stacked base pairs and 32 single-nucleotide dangling-end parameters with unprecedented accuracies: rmsd of 0.28 kcal/mol and 0.41 kcal/mol, respectively. For set-aside test sets, RECCES-Rosetta gives rmsd values of 0.32 kcal/mol on eight stacked pairs involving G-U wobble pairs and 0.99 kcal/mol on seven stacked pairs involving nonstandard isocytidine-isoguanosine pairs. To more rigorously assess RECCES-Rosetta, we carried out four blind predictions for stacked pairs involving 2,6-diaminopurine-U pairs, which achieved 0.64 kcal/mol rmsd accuracy when tested by subsequent experiments. Overall, these results establish that computational methods can now blindly predict energetics of basic RNA motifs, including chemically modified variants, with consistently better than 1 kcal/mol accuracy. Systematic tests indicate that resolving the remaining discrepancies will require energy function improvements beyond simply reweighting component terms, and we propose further blind trials to test such efforts.

Interaction between Pin1 and its natural product inhibitor epigallocatechin-3-gallate by spectroscopy and molecular dynamics simulations

The binding of epigallocatechin-3-gallate (EGCG) to wild type Pin1 in solution was studied by spectroscopic methods and molecular dynamics simulations in this research to explore the binding mode and inhibition mechanism. The binding constants and number of binding sites per Pin1 for EGCG were calculated through the Stern-Volmer equation. The values of binding free energy and thermodynamic parameters were calculated and indicated that hydrogen bonds, electrostatic interaction and Van der Waals interaction played the major role in the binding process. The alterations of Pin1 secondary structure in the presence of EGCG were confirmed by far-UV circular dichroism spectra. The binding model at atomic-level revealed that EGCG was bound to the Glu12, Lys13, Arg14, Met15 and Arg17 in WW domain. Furthermore, EGCG could also interact with Arg69, Asp112, Cys113 and Ser114 in PPIase domain.

Leaf physico-chemical and physiological properties of maize (Zea mays L.) populations from different origins

In this study we evaluated the leaf surface properties of maize populations native to different water availability environments. Leaf surface topography, wettability and gas exchange performance of five maize populations from the Sahara desert, dry (south) and humid (north-western) areas of Spain were analysed. Differences in wettability, stomatal and trichome densities, surface free energy and solubility parameter values were recorded between populations and leaf sides. Leaves from the humid Spanish population with special regard to the abaxial side, were less wettable and less susceptible to polar interactions. The higher wettability and hydrophilicity of Sahara populations with emphasis on the abaxial leaf surfaces, may favour dew deposition and foliar water absorption, hence improving water use efficiency under extremely dry conditions. Compared to the other Saharan populations, the dwarf one had a higher photosynthesis rate suggesting that dwarfism may be a strategy for improving plant tolerance to arid conditions. The results obtained for different maize populations suggest that leaf surfaces may vary in response to drought, but further studies will be required to examine the potential relationship between leaf surface properties and plant stress tolerance.

Theoretical study of size dependent properties of CdSe quantum dots

The size dependent properties of CdSe quantum dots on physical, elastic, thermodynamical and transport properties have been studied theoretically. It is found that at nanometer scale, the surfaces of quantum dots play a crucial role in the changing of its properties. Further, the percentage of atoms at surface, Gibbs free energy and lattice parameter decreases with the increase in size, while rest of the properties like cohesive energy, melting temperature, Debye temperature, heat of mixing, entropy of mixing etc., increases with the increase in particle size confirming the validity of the model. The calculated values follow the same trend as the experimental observations.

The anisotropy of hexagonal close-packed and liquid interface free energy using molecular dynamics simulations based on modified embedded-atom method

This work aims to comprehensively study the anisotropy of the hexagonal close-packed (HCP)-liquid interface free energy using molecular dynamics (MD) simulations based on the modified-embedded atom method (MEAM). As a case study, all the simulations are performed for Magnesium (Mg). The solid–liquid coexisting approach is used to accurately calculate the melting point and melting properties. Then, the capillary fluctuation method (CFM) is used to determine the HCP-liquid interface free energy (γ) and anisotropy parameters. In CFM, a continuous order parameter is employed to accurately locate the HCP-liquid interface location, and the HCP symmetry-adapted spherical harmonics are used to expand γ in terms of its anisotropy parameters (ε20, ε40, ε60 and ε66). Eight slip and twinning planes (basal, two prismatic, two pyramidal, and three twinning planes) are considered as the HCP-liquid interface planes. An average HCP-liquid interface free energy of 122.2 (mJ/m2), non-zero ε20, ε40, and ε66 parameters, and approximately zero ε60 parameter for Mg are predicted. Using these findings, the first preferred dendrite growth direction in solidification of Mg is predicted as [112¯0], which is in agreement with experiments. Also, a second preferred dendrite growth direction for Mg is predicted as [336¯2].

Landau-Ginzburg description of anomalous properties of novel room temperature multiferroics Pb(Fe1/2Ta1/2)x(Zr0.53Ti0.47)1-xO3 and Pb(Fe1/2Nb1/2)x(Zr0.53Ti0.47)1−xO3

Landau-Ginzburg thermodynamic formalism is used for the description of the anomalous ferroelectric, ferromagnetic, and magnetoelectric properties of Pb(Fe1/2Ta1/2)x(Zr0.53Ti0.47)1−xO3 and Pb(Fe1/2Nb1/2)x(Zr0.53Ti0.47)1−xO3 micro-ceramics. We calculated temperature, composition, and external field dependences of ferroelectric, ferromagnetic, and antiferromagnetic phases transition temperatures, remanent polarization, magnetization, hysteresis loops, dielectric permittivity, and magnetoelectric coupling. Special attention was paid to the comparison of developed theory with experiments. It appeared possible to describe adequately main experimental results including a reasonable agreement between the shape of calculated and measured hysteresis loops and remnant polarization. Since Landau-Ginzburg thermodynamic formalism appertains to single domain properties of a ferroic, we did not aim to describe quantitatively the coercive field under the presence of realistic poly-domain switching. Information about linear and nonlinear magnetoelectric coupling coefficients was extracted from the experimental data. From the fitting of experimental data with theoretical formula, we obtained the composition dependence of Curie-Weiss constant that is known to be inversely proportional to harmonic (linear) dielectric stiffness, as well as the strong nonlinear dependence of anharmonic parameters in free energy. Keeping in mind the essential influence of these parameters on multiferroic properties, the obtained results open the way to govern practically all the material properties with the help of suitable composition choice. A forecast of the strong enough influence of antiferrodistortive order parameter on the transition temperatures and so on the phase diagrams and properties of multiferroics are made on the basis of the developed theory.

Influence of downstream pressure on pervaporation properties of PDMS and POMS based membranes

Abstract Properties of one POMS and two PDMS based (Pervatech, Pervap 4060) membranes in recovery of various organic components (acetone, butanol, ethanol, ethyl acetate) from aqueous binary mixtures (4 wt.% of organics) were determined during pervaporation at various permeate pressures (1–25 mbar). Performances of membranes were compared, finding that Pervap 4060 is the most effective membrane in all systems tested, whereas Pervatech is the least effective. Permeances of organics and water increased with an increase of pressure on the permeate side in the most of the tested binary aqueous mixtures. Selectivity of the tested membranes towards organics was improved by increase of permeate pressure. Comparing the effectiveness of membranes, it was found that it is related to the hydrophobicity of membranes expressed by surface free energy (SFE) parameter. SFE changes in the following order: Pervap 4060 > POMS > Pervatech. Membrane performances also follow this order during pervaporation.

Genetic variability of free energy in a function of drought tolerance in common bean accessions

Characterisation of bean genotypes, particularly local landraces is important for ongoing breeding programs, especially for drought tolerance. Susceptibility to drought is emphasized when bean is grown as a stubble crop and sown at the middle of summer. The aim of this study was to compare variability of ten bean genotypes to optimal (25?C) and higher (30?C) temperatures in combination with optimal (80%) and reduced (40%) field water capacity (FWC), from the point of growth (root and shoot length and fresh matter accumulation) and thermodynamic parameters of free energy (calculated parameter after drying at 60?C, 105?C and 130?C) during the early seedlings stage. Significant and positive correlation between root length and fresh matter with free energy at symplast and chemically bound water occurred under temperature stress (i.e. 30?C). Root growth and elongation were affected by drought stress, i.e. under a combination of high temperature (30?C) and water deficit (40% FWC). Based on higher energy consumption, the ability of shoot to continue a growth in stressful conditions could be possible to achieve, as was confirm through significant and positive correlation between evaluated growth parameters in shoot and free energy of free water. It could be concluded that most of the examined dry bean accessions expressed some sensitivity to stress applied. Among genotypes tested, local landrace zecak expressed lesser susceptibility to stresses applied. Accession Maksa was more tolerant to changes at cytoplasmic level, while Medijana and Sataja 425 expressed root i.e. shoot stress tolerance. Those accessions could be considered as potentially drought tolerant genotypes.

Phase behavior and second osmotic virial coefficient for competitive polymer solvation in mixed solvent solutions

We apply our recently developed generalized Flory-Huggins (FH) type theory for the competitive solvation of polymers by two mixed solvents to explain general trends in the variation of phase boundaries and solvent quality (quantified by the second osmotic virial coefficient B2) with solvent composition. The complexity of the theoretically predicted miscibility patterns for these ternary mixtures arises from the competitive association between the polymer and the solvents and from the interplay of these associative interactions with the weak van der Waals interactions between all components of the mixture. The main focus here lies in determining the influence of the free energy parameters for polymer-solvent association (solvation) and the effective FH interaction parameters {χαβ} (driving phase separation) on the phase boundaries (specifically the spinodals), the second osmotic virial coefficient B2, and the relation between the positions of the spinodal curves and the theta temperatures at which B2 vanishes. Our classification of the predicted miscibility patterns is relevant to numerous applications of ternary polymer solutions in industrial formulations and the use of mixed solvent systems for polymer characterization, such as chromatographic separation where mixed solvents are commonly employed. A favorable comparison of B2 with experimental data for poly(methyl methacrylate)/acetonitrile/methanol (or 1-propanol) solutions only partially supports the validity of our theoretical predictions due to the lack of enough experimental data and the neglect of the self and mutual association of the solvents.

RNA Thermodynamic Structural Entropy.

Conformational entropy for atomic-level, three dimensional biomolecules is known experimentally to play an important role in protein-ligand discrimination, yet reliable computation of entropy remains a difficult problem. Here we describe the first two accurate and efficient algorithms to compute the conformational entropy for RNA secondary structures, with respect to the Turner energy model, where free energy parameters are determined from UV absorption experiments. An algorithm to compute the derivational entropy for RNA secondary structures had previously been introduced, using stochastic context free grammars (SCFGs). However, the numerical value of derivational entropy depends heavily on the chosen context free grammar and on the training set used to estimate rule probabilities. Using data from the Rfam database, we determine that both of our thermodynamic methods, which agree in numerical value, are substantially faster than the SCFG method. Thermodynamic structural entropy is much smaller than derivational entropy, and the correlation between length-normalized thermodynamic entropy and derivational entropy is moderately weak to poor. In applications, we plot the structural entropy as a function of temperature for known thermoswitches, such as the repression of heat shock gene expression (ROSE) element, we determine that the correlation between hammerhead ribozyme cleavage activity and total free energy is improved by including an additional free energy term arising from conformational entropy, and we plot the structural entropy of windows of the HIV-1 genome. Our software RNAentropy can compute structural entropy for any user-specified temperature, and supports both the Turner’99 and Turner’04 energy parameters. It follows that RNAentropy is state-of-the-art software to compute RNA secondary structure conformational entropy. Source code is available at https://github.com/clotelab/RNAentropy/; a full web server is available at http://bioinformatics.bc.edu/clotelab/RNAentropy, including source code and ancillary programs.

Mass dependence of the activation enthalpy and entropy of unentangled linear alkane chains.

The mass scaling of the self-diffusion coefficient D of polymers in the liquid state, D ∼ M(β), is one of the most basic characteristics of these complex fluids. Although traditional theories such as the Rouse and reptation models of unentangled and entangled polymer melts, respectively, predict that β is constant, this exponent for alkanes has been estimated experimentally to vary from -1.8 to -2.7 upon cooling. Significantly, β changes with temperature T under conditions where the chains are not entangled and at temperatures far above the glass transition temperature Tg where dynamic heterogeneity does not complicate the description of the liquid dynamics. Based on atomistic molecular dynamics simulations on unentangled linear alkanes in the melt, we find that the variation of β with T can be directly attributed to the dependence of the enthalpy ΔHa and entropy ΔSa of activation on the number of alkane backbone carbon atoms, n. In addition, we find a sharp change in the melt dynamics near a "critical" chain length, n ≈ 17. A close examination of this phenomenon indicates that a "buckling transition" from rod-like to coiled chain configurations occurs at this characteristic chain length and distinct entropy-enthalpy compensation relations, ΔSa ∝ ΔHa, hold on either side of this polymer conformational transition. We conclude that the activation free energy parameters exert a significant influence on the dynamics of polymer melts that is not anticipated by either the Rouse and reptation models. In addition to changes of ΔHa and ΔSa with M, we expect changes in these free energy parameters to be crucial for understanding the dynamics of polymer blends, nanocomposites, and confined polymers because of changes of the fluid free energy by interfacial interactions and geometrical confinement.

3D Growth Kinetics of Precipitates with Anisotropic Interfacial Free Energy: A Phase-Field Study

In this study, we report on the 3D growth kinetics of an isolated β precipitate growing from a supersaturated α matrix. The α-β interfacial energy is assumed to be cubic anisotropic; specifically, either (100) or (111) interfaces are preferred. The diffusivity is maintained a constant in our model; this constant diffusivity is achieved through a combination of Cahn–Hilliard and Allen–Cahn equations (with appropriate choice of model free energy parameters). Our results indicate that depending on the matrix supersaturation, the growth modes can either be shape preserving or non-shape preserving. In the case of shape preserving growth, we are able to verify, that as indicated by the earlier theoretical studies, the classical Zener-Frank theories can be used to predict the growth rates of precipitates.

Comparative antioxidant potency and solvent polarity effects on HAT mechanisms of tocopherols

The antioxidant activity of the four forms of tocopherol has been investigated in gas phase and in different solvents using PBE0/6-31+G(d) level of theory. The three main working mechanisms, homolytic hydrogen atom transfer (HAT), single electron transfer-proton transfer (SET-PT) and sequential proton loss electron transfer (SPLET) have been considered. The O–H bond dissociation free energy (BDFE), ionization potential (IP), proton dissociation free energy (PDFE), proton affinity (PA) and electron transfer free energy (ETFE) parameters have been calculated in gas phase and solvents. The theoretical results show the effect of the substituent position with respect to the phenolic O–H group on the reactivity. The methyl group, in ortho position, lends additional inductive and steric stability to the tocopheroxyl radical and therefore, increases antioxidant activity. α-tocopherol is shown to be the most reactive form in gas phase with the lowest BDFE, IP, and PA values, whereas in all solvents, γ-tocopherol has the lowest PA and PDFE values.The solvent effects are evaluated using an implicit solvation model (IEF-PCM). We have used a good model to calculate the solvation free energy of proton and electron in different media, where proton or electron was attached to one molecule of solvent and the obtained species were optimized using IEF-PCM approach in the same solvent. In gas phase, and non-polar solvents like benzene and toluene, BDFE value is lower than PA and IP, this suggested that HAT would be the most favorable mechanism for explaining the antioxidant activity of tocopherols, whereas SPLET mechanism is thermodynamically preferred in polar solvents like water, DMSO and methanol, where PA value of all forms of tocopherol is considerably lower than BDFE and IP.

Synthesis, and spectroscopic studies of charge transfer complex of 1,2-dimethylimidazole as an electron donor with π-acceptor 2,4-dinitro-1-naphthol in different polar solvents

The charge transfer (CT) complex of 1,2-dimethylimidazole (DMI) as an electron donor with π acceptor 2,4-dinitro-1-naphthol (DNN) has been studied spectrophotometrically in different solvents like chloroform, acetonitrile, methanol, methylene chloride, etc. at room temperature. The CT complex which is formed through the transfer of lone pair electrons from DMI to DNN exhibits well resolved CT bands and the regions of these bands were remarkably different from those of the donor and acceptor. The stoichiometry of the CT complex was found to be 1:1 by a straight-line method between donor and acceptor with maximum absorption bands. The novel CT complex has been characterized by FTIR, TGA–DTA, powder XRD, 1H NMR and 13C NMR spectroscopic techniques. The Benesi–Hildebrand equation has been used to determine the formation constant (KCT), molar extinction coefficient (εCT), standard gibbs free energy (ΔG°) and other physical parameters of the CT complex. The formation constant recorded higher values and molar extinction coefficient recorded lower values in chloroform compared with methylene chloride, methanol and acetonitrile, confirming the strong interaction between the molecular orbital’s of donor and acceptor in the ground state in less polar solvent. This CT complex has been studied by absorption spectra of donor 1,2-dimethylimidazole (DMI) and acceptor 2,4-dinitro-1-naphthol (DNN) by using the spectrophotometric technique in various solvents at room temperature.

Composites prepared from polyurethanes modified with silicone-acrylic nanopowders

Abstract Linear polyurethanes were obtained the reaction of 1,6-hexamethylene diisocyanate with poly(ɛ-caprolactone)diol and butane-1,4-diol. Synthesis was carried out in the presence of 1, 3 and 5 wt.% of polydimethylsiloxane-poly(methyl methacrylate) core–shell nanopowder. Solutions of resulting polyurethanes were cast on PTFE plates and dried at 140 °C to form films. The presence of structures originating from modifier was confirmed by IR and XPS spectroscopy. DSC analysis revealed the presence of crystalline phase in all samples. Contact angles were determined using standard fluids and surface free energy parameters were calculated. The results of these investigations proved that modification with silicone-acrylic nanopowder resulted in significant increase in hydrophobicity of polyurethane surfaces Changes in surface characteristics were also reflected in surface images obtained in AFM studies. It is suggested that the polyurethane composites obtained in this study can be tested as coatings for biomedical applications.

Interfacial Interactions and Nanostructure Changes in DPPG/HD Monolayer at the Air/Water Interface

Lung surfactant (LS) plays a crucial role in regulating surface tension during normal respiration cycles by decreasing the work associated with lung expansion and therefore decreases the metabolic energy consumed. Monolayer surfactant films composed of a mixture of phospholipids and spreading additives are of optional utility for applications in lung surfactant‐based therapies. A simple, minimal model of such a lung surfactant system, composed of 1,2‐dipalmitoyl‐sn‐glycero‐3‐[phosphor‐rac‐(1‐gylcerol)] (DPPG) and hexadecanol (HD), was prepared, and the surface pressure‐area (π‐A) isotherms and nanostructure characteristics of the binary mixture were investigated at the air/water interface using a combination of Langmuir‐Blodgett (LB) and atomic force microscopy (AFM) techniques. Based on the regular solution theory, the miscibility and stability of the two components in the monolayer were analyzed in terms of compression modulus () , excess Gibbs free energy () , activity coefficients (γ), and interaction parameter (ξ). The results of this paper provide valuable insight into basic thermodynamics and nanostructure of mixed DPPG/HD monolayers; it is helpful to understand the thermodynamic behavior of HD as spreading additive in LS monolayer with a view toward characterizing potential improvements to LS performance brought about by addition of HD to lung phospholipids.

Cellulose acetate graft-(glycidylmethacrylate-g-PEG) for modification of AMC ultrafiltration membranes to mitigate organic fouling

A hydrophilic cellulose acetate-graft-(glycidylmethacrylate-g-polyethylene glycol) (CA-g-(GMA-g-PEG)) was synthesized and incorporated into acetylated methyl cellulose (AMC) to prepare antifouling ultrafiltration membranes. The successful synthesis of CA-g-(GMA-g-PEG) was confirmed by 1H-NMR and X-ray photoelectron spectroscopy studies. The AMC blend membranes were characterized by X-ray diffraction (XRD), thermo gravimetric analysis (TGA), scanning electron microscopy (SEM), atomic force microscopy (AFM), confocal laser scanning microscopy (CLSM) and contact angle analysis to investigate the effect of CA-g-(GMA-g-PEG) on the properties of the membrane surface. The increase of CA-g-(GMA-g-PEG) content in the AMC matrix reduced the macrovoids and transformed to a sponge-like structure in the entire membrane cross section. Furthermore, the increase in the graft moiety enhanced the performance of the membranes. Surface free energy parameters calculated from the contact angle measurements indicate that the interfacial free energy of the blend membranes were lower than those of the pure AMC membranes. The modified membrane surface became more hydrophilic and more wettable because of the preferential orientation of these polar groups towards the membrane surface. The efficiency of these membranes in the separation of singlet foulants and multi foulants increased significantly, thus increasing the fouling resistance. These membranes would be useful for organic fouling prevention during water and wastewater treatment.