{"title":"单个微观球体在胶体力场中的布朗运动","authors":"D. Prieve, S. Bike, Nasser A. Frej","doi":"10.1039/DC9909000209","DOIUrl":null,"url":null,"abstract":"Total internal reflection microscopy has been used to monitor the submicroscopic distance separating a microscopic sphere and a transparent plate. Light scattered from an evanescent wave by a single sphere is exponentially sensitive to the elevation of the sphere above the plate. Changes in separation as small as 1 nm are detectable. The technique is virtually instantaneous, non-intrusive, and easily automated. Two applications are discussed: from an equilibrium distribution of separations, a direct measure of the mean potential of surface forces acting on the sphere can be obtained; from an autocorrelation of the separation as a function of time, the sphere's diffusion coefficient, D, can be obtained. Forces as small as 10–13 N can be accurately measured. Owing to its close proximity to the wall, a 10 µm polystyrene sphere in 0.5 mmol dm–3 NaCl has a value of D of ca. 2% of the bulk value. The fractional reduction in D suggests that the sphere resides ca. 100 nm above the glass plate.","PeriodicalId":12210,"journal":{"name":"Faraday Discussions of The Chemical Society","volume":"23 18 1","pages":"209-222"},"PeriodicalIF":0.0000,"publicationDate":"1990-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"36","resultStr":"{\"title\":\"Brownian motion of a single microscopic sphere in a colloidal force field\",\"authors\":\"D. Prieve, S. Bike, Nasser A. Frej\",\"doi\":\"10.1039/DC9909000209\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Total internal reflection microscopy has been used to monitor the submicroscopic distance separating a microscopic sphere and a transparent plate. Light scattered from an evanescent wave by a single sphere is exponentially sensitive to the elevation of the sphere above the plate. Changes in separation as small as 1 nm are detectable. The technique is virtually instantaneous, non-intrusive, and easily automated. Two applications are discussed: from an equilibrium distribution of separations, a direct measure of the mean potential of surface forces acting on the sphere can be obtained; from an autocorrelation of the separation as a function of time, the sphere's diffusion coefficient, D, can be obtained. Forces as small as 10–13 N can be accurately measured. Owing to its close proximity to the wall, a 10 µm polystyrene sphere in 0.5 mmol dm–3 NaCl has a value of D of ca. 2% of the bulk value. The fractional reduction in D suggests that the sphere resides ca. 100 nm above the glass plate.\",\"PeriodicalId\":12210,\"journal\":{\"name\":\"Faraday Discussions of The Chemical Society\",\"volume\":\"23 18 1\",\"pages\":\"209-222\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"1990-01-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"36\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Faraday Discussions of The Chemical Society\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1039/DC9909000209\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Faraday Discussions of The Chemical Society","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1039/DC9909000209","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
Brownian motion of a single microscopic sphere in a colloidal force field
Total internal reflection microscopy has been used to monitor the submicroscopic distance separating a microscopic sphere and a transparent plate. Light scattered from an evanescent wave by a single sphere is exponentially sensitive to the elevation of the sphere above the plate. Changes in separation as small as 1 nm are detectable. The technique is virtually instantaneous, non-intrusive, and easily automated. Two applications are discussed: from an equilibrium distribution of separations, a direct measure of the mean potential of surface forces acting on the sphere can be obtained; from an autocorrelation of the separation as a function of time, the sphere's diffusion coefficient, D, can be obtained. Forces as small as 10–13 N can be accurately measured. Owing to its close proximity to the wall, a 10 µm polystyrene sphere in 0.5 mmol dm–3 NaCl has a value of D of ca. 2% of the bulk value. The fractional reduction in D suggests that the sphere resides ca. 100 nm above the glass plate.