adsorption of alcohols on low energy polymer surfaces.

by William John Murphy in Bradford

Written in English
Published: Downloads: 331
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Edition Notes

Ph.D. thesis. Typescript.

SeriesTheses
The Physical Object
Pagination1 vol
ID Numbers
Open LibraryOL13692688M

The evaluation of thermodynamic parameters describes the spontaneous, endothermic and chemisorption adsorption process while activation energy reveals the physical adsorption mechanism. Therefore, the coordination effects among OPB, MWCNTs and PVA polymer hydrogels can produce a promising adsorbent material for wastewater treatment applications.   The appearance of signals below mM are likely from impurities such as unsulfated alcohols, which have been observed in various commercial SDS products. 39, 53 These fatty alcohols can successfully compete with SDS for surface adsorption sites at SDS solution concentrations below mM and remain in the surface film at least until the. Adsorption is the adhesion of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface. This process creates a film of the adsorbate on the surface of the process differs from absorption, in which a fluid (the absorbate) is dissolved by or permeates a liquid or solid (the absorbent), respectively. Adsorption is a surface phenomenon, while absorption involves. It was found that the polymer has a high affinity with the solvent and each monomer unit has on average hydrogen bonds. The structural and energy characteristics of the polymer adsorption were investigated at different initial positions of the poly(N-vinylpyrrolidone) macromolecule relative to the cellulose fragment.

The highest protein adsorption occurred on surfaces containing the highest amount of hydroxyl groups on the surface (from the % HEMA surfaces). This was initially surprising, as hydroxyl groups have been noted to be hydrophilic in nature and are generally correlated with low protein adsorption on such surfaces as hydroxyl terminated self.   In case of polymer-treated mild steel, appearance of peaks around 3,, 3,, 2,, and 1, cm −1 confirms the adsorption of PVAP on the metal surface. Moreover the intensity of the peaks corresponds to Fe 2 O 3 has been reduced indicating less pronounced attack of the acid on MS in presence of PVAP. Oxidized PDMS surfaces undergo hydrophobic recovery where the PDMS surface returns to its original hydrophobic nature within about min of exposure to air. 25, 26 Almost all theories explaining this phenomena include the importance of low molecular weight polymer chains (often oligomers) from the bulk migrating in some way to the surface. The proceedings cover six major areas of research related to chemical flooding processes for enhanced oil recovery, namely, 1) Fundamental aspects of the oil displacement process, 2) Micro­ structure of surfactant systems, 3) Emulsion rheology and oil dis­ placement mechanisms, 4) Wettability and oil displacement mecha­ nisms, 5) Adsorption.

  Because of extensive applications in industrial and environmental monitoring, biomedicines and pharmaceutics, etc., gas sensors are being focused widely by the research community since a few decades. Generally, gas-sensing materials include semiconducting metal oxides, vapour sensitive polymer, porous silicon, etc. Based on the gas-sensing principle of adsorption/desorption . adsorption on a nickel () surface. The adsorption energy is the difference between twice the Ni — H bond energy and the heat of H. 2. dissociation ( kJ/mol): E. ad = 2 E. Me-H -E. diss. CO-Pd interaction potential. Terminology: associative and dissociative adsorption. H. 2. The permeability of tight gas reservoirs is usually lower than 1 md. When the external fluids from drilling and completion processes invade such reservoirs, formation damage occurs and causes serious damage to oil and gas production. Fluorocarbon surfactants are most often recommended for removing such damage because they have extremely low surface tension, which means that they can change the. For citric acid, a high adsorption density on alumina was measured over a broad pH range, whereas the adsorption of PVA is very low. The adsorption density of citric acid on alumina is not influenced by the presence of PVA, whereas the polymer is displaced by citric acid from the alumina surface.

adsorption of alcohols on low energy polymer surfaces. by William John Murphy Download PDF EPUB FB2

The adsorption of a range of polyvinyl alcohols, containing 12% residual acetyl groups, by sodium, calcium, and cesium montmorillonites has been studied. The polymers were strongly adsorbed by the clays.

The amount of polymer adsorbed depended on the method of mixing the polymer solution and the clay. When maximum adsorption was attained the amount of polymer adsorbed was sufficient to form Cited by: Alcohols are a significant group of surfactants which have been employed extensively in industry to improve the interfacial effects.

Recently, the change in surface potential (ΔV) of two isomeric hexanols, methyl isobutyl carbinol (MIBC) and 1-hexanol, was investigated by using an ionizing Am electrode. It clearly showed the opposite effects between MIBC and 1-hexanol in the interfacial Cited by: Contact angle studies of some low energy polymer surfaces.

Murphy, M. Roberts and these lower values are attributed to the preferential adsorption of the alcohol molecules at both the polymer-liquid and the polymer-vapour interfaces.

books or book chapters) do not need to formally request permission to reproduce material Cited by: All of the alcohols adsorb at low temperature by forming alkoxy and hydroxyl species on the surface.

On fully oxidized CeO 2 (), recombination occurs between some of the alkoxys and hydroxyls, resulting in alcohol desorption near by: Polymer adsorption by nanoparticles improves the stability of these types of suspensions against aggregation.

In this work, the surface adsorption of polyethylene glycol (PEG) and polyvinyl alcohol (PVA) with different molecular weights onto the Zinc oxide (ZnO) nanoparticles is studied. The effects of solution pH value andCited by: The neutral polymer, polyvinyl alcohol, has been shown to be adsorbed by the hydrated oxides gibbsite and goethite.

A reduction in adsorption on gibbsite is observed when it is dried prior to the. Like low-pressure plasma treatment, irradiation of a polymer surface with low energy ions promotes its adhesion to metals. Due to the complexity of the plasma–polymer interaction there are still many unresolved questions regarding the contribution and the efficiency of the surface modification by different particles generated in the plasma.

A statistical‐mechanical treatment of a polymer molecule adsorbed on a solid surface is given. The surface coverage by adsorbed molecules is assumed to be sufficiently low that the interactions of the adsorbed polymer molecules with each other may be neglected.

The partition function is derived for a polymer molecule with sequences of repeating units adsorbed at an interface and with. To improve methane storage capacity of porous organic materials, this work demonstrates that a rigid ladder-type backbone is more entropically favorable for gas adsorption and leads to a high gas uptake per unit surface area.

A porous ladder polymer network was designed and synthesized as the model material via cross-coupling polymerization and subsequent ring-closing olefin metathesis.

PEO is recognized as a polymer exhibiting low protein adsorption and low cell adhesion due to its minimal interfacial free energy with water, hydrophilicity, high-surface mobility and steric stabilization effects, and unique solution properties and molecular conformation in water. For these materials, the water CAs were above ∼°/° (adv/rec) and BET C constants were in the range of ∼, indicating uniform low-energy surfaces of closely packed alkyl groups on.

This correlates with the regions of emulsion stability at both high and low polymer concentrations, such that the instabilities arise in the regions of low or zero surface charge.

The results presented and their interpretation represent a development in the understanding of polymer–surfactant adsorption at the oil–water interface.

about the surface species during adsorption and reaction lowest energy barrier was kJmol presence of a network of hydrogen-bonded -SO3H groups at low alcohol concentrations and. Kink sites on high Miller index surfaces are either left- or right-handed and can be thought of as chiral, when the step lengths on either side of the kink site are unequal.

A silver single crystal was oriented and cut to expose the Ag() surface on one side and the Ag(6̄4̄3̄) surface on the other side. A system is proposed for naming these surfaces as Ag()S and Ag()R, respectively.

Purchase Hydrophobic Surfaces - 1st Edition. Print Book & E-Book. ISBN  It is important to mention that several studies have already been done on the separation of short-chain alcohols by adsorption, mostly on silica aerogels and their organic derivatives, zeolites [29,30], activated carbons and polymer resins [, ], as adsorption requires less energy compared to other separation technologies.

Studies on the separation of alcohols by polymeric/co-polymeric gels. Present book chapter deals with production and potential applications of nanocarbon and nanocarbon-polymer composite materials, with special attention on the energy and environmental related sector and their significant role in enhancing the efficacy for.

Adsorption is the adhesion of ions or molecules onto the surface of another phase. Adsorption may occur via physisorption and chemisorption. Ions and molecules can adsorb to many types of surfaces including polymer surfaces.

A polymer is a large molecule composed of repeating subunits bound together by covalent adsorption of ions and molecules to polymer surfaces plays a role.

The added surfactant may also adsorb onto the membrane surface, 41 and thus reduce the interfacial free ene42 and promote adhesion and, subsequently, chemical attachment of the polymer to. This book documents the proceedings of the Fourth International Symposium on Polymer Surface Modification: Relevance to Adhesion held under the auspices of MST Conferences, LLC in Orlando, FL, JunePolymers are used for a variety of purposes in a host of technological applications and even a cursory look at the literature will evince that currently there is.

Penn et al. studied the chemisorption kinetics of amino-functionalised polystyrene chains on epoxy-functionalised flat surfaces in the presence of good and poor solvents. Figure shows the comparative kinetic curves for amino mono-functional polystyrene chemisorption, as derived from their reported results.

The system characteristics correspond to a true surface-linked polymer brush (2R g. The adsorption of surface-active molecules at a solid/liquid interface provides a versatile tool for modification and structuring of polymer surfaces.

The effect of oxyethylene groups on the adsorption properties of fatty alcohol polyoxyethylene ether sodium sulfate with narrow ethylene oxide distribution (AE m S, m = 3, 5, 7, 9) was characterized by means of the equilibrium surface tension, the dynamic surface tension and the contact angle.

The results show that at a concentration lower than the critical micelle concentration (CMC) the. The adsorption of polymers affects the cost and oil recovery in oil reservoir exploitation and the flocculation effect in the treatment of oil sand tailings.

The adhesion and adsorption of a hydrophobically modified polyacrylamide (HMPAM), i.e., P(AM-NaAA-C 16 DMAAC), on silica and asphaltene were investigated using surface force measurements, thermodynamic analysis and quartz crystal.

Bioethanol is used widely as a solvent and is considered a potential liquid fuel. Ethanol can be produced from biomass by fermentation, which results in low concentrations of alcohol in water. Conventional distillation is normally used to separate ethanol from water, but it required high energy consumption.

Therefore, alternative approaches to this separation are being pursued. Adsorption and desorption behavior of ionic and nonionic surfactants on polymer surfaces†. The adsorption behavior of polyvinyl alcohol (PVA) on the CaCO3/solution interface under the influence of sodium oleate (SOl) interaction was investigated by the adsorbed amount, FTIR spectra, X-Ray diffraction and zeta potential.

Effects of solid to liquid ratio and temperature was also examined. Observed increase of the PVA adsorption in presence of the sodium oleate resulted from a polymer. The polyimides exhibit large adsorption capacities for organic vapors such as benzene ( wt%) and cyclohexane ( wt%) at K and P/P o = In addition, the low-surface-energy trifluoromethyls significantly decrease the water uptake in the fluorinated polyimide compared to.

The primary approach used is through chemical modification of the surface through polymer coatings (Figure 3). Such coating provide a ‘stealth’ effect, [14] which is attributed to the high level of hydration of the hydrophilic polymer backbones, steric repulsion, and reduction of the surface energy of the biomaterial [6,].

Moreover, very few hydrogen bonds are formed between the adsorbate and the PVA surface, since both the protein fragments and the polymer chains separately optimize these interactions. Additional molecular dynamics simulations in explicit solvent were also performed to study the hydration of the adsorbed fragments and to estimate the possible.

The polymer-mineral composites were synthesized using vinyl monomers styrene, methyl acrylate, and butyl acrylate with nano dispersed oxides Fe 2 O 3, Cr 2 O 3, V 2 O 5 and SiO 2 in the presence of benzoyl peroxide and other peroxide initiators. Benzoyl peroxide adsorption on Fe 2 O 3, Cr 2 O 3, and V 2 O 5 surfaces was studied.

The adsorption parameters were found: adsorption-desorption.The London dispersive surface free energy (γ S L) was calculated using the Schultz and Dorris–Gray method.

The maximum surface energy value of (P(VDC-co-AN)) is found to be mJm − 2 and mJm − 2 in both methods respectively.If surface energy is decreased to below 60 mN m-1 by adding more propanol to the water/propanol mixture used as substrate, molecules with long side chains (n = ) that readily break on a /0.