Colloids and Surfaces最新文献_第3页

The relative solution and interfacial hydrophobicity of ethylene oxide—propylene oxide—ethylene oxide block copolymers 环氧乙烷-环氧丙烯-环氧乙烷嵌段共聚物的相对溶液及界面疏水性

Colloids and Surfaces Pub Date : 1992-12-11 DOI: 10.1016/0166-6622(92)80225-Q

Patrick W. Houlihan, Daniel Fornasiero , Franz Grieser, Thomas W. Healy

{"title":"The relative solution and interfacial hydrophobicity of ethylene oxide—propylene oxide—ethylene oxide block copolymers","authors":"Patrick W. Houlihan, Daniel Fornasiero , Franz Grieser, Thomas W. Healy","doi":"10.1016/0166-6622(92)80225-Q","DOIUrl":"10.1016/0166-6622(92)80225-Q","url":null,"abstract":"<div>By varying the ratio of the ethylene oxide (EO) to propylene oxide (PO) units in a series of poly(ethylene oxide—propylene oxide—ethylene oxide) (EPE) non-ionic copolymers we have been able to quantify the relative hydrophobic energy contribution of the EO and PO units in bulk solution and interfacial processes. These polymers are known to form aggregates in solution which consist of a hydrophobic PO core surrounded by a hydrophilic EO shell. In order to determine the hydrophobic character of the respective EPE polymers the partitioning of pyrene, a strongly hydrophobic probe, between the aqueous environment and the hydrophobic polymer environment was monitored as a function of polymer concentration. Aggregate hydrophobicity was found to be dependent on both the EO and PO chain lengths such that the hydrophobic contribution per PO unit is ten times the hydrophilic contribution per EO unit. The ability of EPE to stabilise an aqueous colloidal dispersion of hydrophobic particles (carbon black) was measured as a function of EPE concentration. The critical stabilisation concentration, which represents the onset of colloidal stability, was round to be inversely related to the hydrophobicity of the polymer aggregates in the bulk solution. The information gathered in this study allows the optimum EO:PO:EO ratio for stabilisation of a hydrophobic colloidal dispersion to be predicted.</div>","PeriodicalId":10488,"journal":{"name":"Colloids and Surfaces","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1992-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0166-6622(92)80225-Q","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75476399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Evidence of complexation between poly(acrylic acid) and sodium dodecyl sulfate 聚丙烯酸和十二烷基硫酸钠之间络合的证据

Colloids and Surfaces Pub Date : 1992-12-11 DOI: 10.1016/0166-6622(92)80228-T

C. Maltesh, P. Somasundaran

引用次数: 21

Interfacial phenomena affecting the adhesion of Thiobacillus ferrooxidans to sulphide mineral surface 影响氧化亚铁硫杆菌与硫化物矿物表面粘附的界面现象

Colloids and Surfaces Pub Date : 1992-12-11 DOI: 10.1016/0166-6622(92)80227-S

Jaime A. Solari , Gladys Huerta, Blanca Escobar, Tómas Vargas, Ricardo Badilla-Ohlbaum, Jorge Rubio

{"title":"Interfacial phenomena affecting the adhesion of Thiobacillus ferrooxidans to sulphide mineral surface","authors":"Jaime A. Solari , Gladys Huerta, Blanca Escobar, Tómas Vargas, Ricardo Badilla-Ohlbaum, Jorge Rubio","doi":"10.1016/0166-6622(92)80227-S","DOIUrl":"10.1016/0166-6622(92)80227-S","url":null,"abstract":"<div>The electrokinetic and hydrophobic properties of the autotrophic bacteria Thiobacillus ferrooxidans as well as selected minerals have been studied by microelectrophoresis, contact angle and hexadecane/aqueous phase partition measurements. Adhesion measurements were conducted on sized fractions of quartz, pyrite, chalcopyrite and other copper sulphides in order to establish the relationships between cell surface properties and cell adhesion to specific mineral surfaces. It was found that the bacteria had an isoelectric point at pH 3.0 and that they were slightly hydrophobic, showing a water contact angle of 20–24 and extraction recoveries into hexadecane in the range 14–22 wt.% Adhesion mechanisms involved in the interaction between Thiobacillus ferrooxidans and mineral surfaces as a function of the electrokinetic and hydrophobic properties of bacteria and minerals are illustrated. Calculated free energies of bacterial adhesion to quartz, chalcopyrite and pyrite indicated that adhesion appears to occur at the secondary minimum according to the Derjaguin—Landau—Verwey—Overbeek theory.</div>","PeriodicalId":10488,"journal":{"name":"Colloids and Surfaces","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1992-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0166-6622(92)80227-S","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81340617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 77

Empirical ion activity products for Fe(OH)3 estimated from the interaction between 59Fe(III) (14C)EDTA and soils 根据59Fe(III) (14C)EDTA与土壤的相互作用估计Fe(OH)3的经验离子活度产物

Colloids and Surfaces Pub Date : 1992-12-11 DOI: 10.1016/0166-6622(92)80220-V

Á. Hargitai-Tóth

引用次数: 0

The behaviour of surfactants in concentrated acids 6. Micellization and interfacial behaviour of n-hexadecyltrimethylammonium bromide in mixtures of methane sulphonic acid and concentrated sulphuric acid 表面活性剂在浓酸中的行为正十六烷基三甲基溴化铵在甲烷磺酸和浓硫酸混合物中的胶束化和界面行为

Colloids and Surfaces Pub Date : 1992-11-23 DOI: 10.1016/0166-6622(92)80232-Q

Annerose Müller, Steffen Giersberg

{"title":"The behaviour of surfactants in concentrated acids 6. Micellization and interfacial behaviour of n-hexadecyltrimethylammonium bromide in mixtures of methane sulphonic acid and concentrated sulphuric acid","authors":"Annerose Müller, Steffen Giersberg","doi":"10.1016/0166-6622(92)80232-Q","DOIUrl":"10.1016/0166-6622(92)80232-Q","url":null,"abstract":"<div>The surface and interfacial activity of cationic surfactants depends on the polarity of the bulk phase. If concentrated sulphuric acid is mixed with water, physical properties such as density, and surface and interfacial tension go through a maximum as the molar composition is changed. Also the properties of surfactants, i.e. surface activity and CMC, do not vary linearly in such aqueous mixtures. However, if concentrated sulphuric acid is mixed with methane sulphonic acid we find a linear relationship.The adsorption isotherms of n-hexadecyltrimethylammonium bromide at the surface (interface) of mixtures of H2SO4 and CH3SO3H/air (n-hexane) and the CMC were determined for various compositions of the acid phase and approximated by the Von Szyskowski equation. The change in the energy of micelle formation, — ΔMG, and the energy of adsorption, — ΔAG°, were calculated as a function of solvent composition. The surface concentration as a function of bulk concentration, the maximum surface coverage and the percentage surface concentration were also calculated.We found a linear dependence of the CMC, and of the lowering of σ and γ at the CMC, on the mole fraction of the acid phase. Also the constant A of the Von Szyskowski equation decreases and the logarithm of B increases linearly with the mole fraction of methane sulphonic acid. Therefore it is possible to calculate all the data needed for the characterization of systems of different acid composition. A special pattern was found for acid mixtures with XCH3SO3H < 0.1. This can be explained by the transformation of micelle structure and the possibility that micelles can solubilize hydrocarbons in this region.</div>","PeriodicalId":10488,"journal":{"name":"Colloids and Surfaces","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1992-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0166-6622(92)80232-Q","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90582924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Light scattering characterization of constituent copolymers from polyacrylate latices 聚丙烯酸酯乳液组成共聚物的光散射特性

Colloids and Surfaces Pub Date : 1992-11-23 DOI: 10.1016/0166-6622(92)80235-T

J. Stejskal , O. Quadrat , P. Bradna , J. Šňupárek

引用次数: 3

Anionic surfactant adsorption on to asphalt-covered clays 阴离子表面活性剂在沥青覆盖粘土上的吸附

Colloids and Surfaces Pub Date : 1992-11-23 DOI: 10.1016/0166-6622(92)80237-V

B. Siffert, A. Jada, E. Wersinger

引用次数: 7

Static and quasi-elastic light scattering of an aggregating colloidal suspension 聚集体胶体悬浮液的静态和准弹性光散射

Colloids and Surfaces Pub Date : 1992-11-23 DOI: 10.1016/0166-6622(92)80240-3

Stephen D.T. Axford, Thelma M. Herrington, B.R. Midmore