251. Interactions between adsorbed macromolecules : measurements on emulsions and liquid films
- Author
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Lyklema, J., van Vliet, T., Lyklema, J., and van Vliet, T.
- Abstract
The aim of this study was to gain more insight into the factors, determining the inter- and intramolecular interactions between adsorbed macromolecules. To that end several experimental and theoretical approaches were followed, using well-defined systems. It was shown that these interactions could conveniently be studied by measurements on emulsions and thin free liquid films. Two different macromolecules were used: a nonionic one: polyvinyl alcohol (PVA) and an ionic one: a copolymer of methacrylic acid and the methyl ester of methacrylic acid (PMA-pe) in the molar ratio 2:1.The characterization of the used materials has been described in chapter 2. The conformational transition, occurring in dissolved polymethacrylates was briefly discussed. At low pH, the molecules occur in a compact form, the hypercoiled form, or a-conformation. At pH above ~ 6 the molecules occur in the common. more extended b-conformation. From viscometry on PVA solutions conformational parameters, such as the root mean square end-to-end distance, the length of a statistical chain element and the linear expansion factor were determined. These conformational parameters were determined in a I M aqueous glycerol solution because in the film experiments 1 M glycerol was present in the PVA solutions in order to lower the water vapour pressure.In chapter 3 the experimental methods have been described. In the first part attention was paid to the preparation of the emulsions and to the determination of basic properties, such as specific area and adsorbed amount. A variety of rheological measurements were described in the second part. A more detailed description was given of the apparatus for the dynamic measurements (the rheometer) and of that for creep measurements.The end of chapter 3 deals with the thickness measurements of polymerstabilized free liquid films. First, a description of the apparatus and the experimental procedure was given. Subsequently, a discussion followed of the calculation of th
- Published
- 1977