General theory of grain boundaries in crystal

Presented is a microscopic derivation of the theory of grain boundaries in crystal. Fundamental properties of the grain boundaries are also discussed.     

Stress birefringence in amorphous polymers under nonisothermal conditions

The relationship of birefringence to stress in an amorphous polymer was studied, with emphasis on conditions of high stress and rapid cooling. The latter (nonisothermal) conditions are important in connection with studies of polymer processing operations. Polystyrene was pulled at a constant elongation rate (0.075 to 2 sec^?1 in the present and related work) under both isothermal conditions (in the range 120 to 157°C) and nonisothermal conditions (with cooling rates in the range 0.6 to 1.7°C/sec). Generally we conclude that stress in proportional to birefringence under a wide range of conditions, except that a nonlinear regime appears at stresses higher than about 10⁷ dyn/cm². In this regime, stress increases more rapidly with deformation than does birefringence.     

Electrocapillary phenomena at oil-water interfaces

Summary The electrocapillary phenomena at oil-water interfaces, i. e. the change in the interfacial tension with an applied potential difference, take place over a moderate polarization range of ca. 20 to –20 V, when the systems have sufficiently high electric conductance and contain surface active agents. Experiments were carried out in the presence of potassium chloride in the aqueous phase and ionic surface active agents in the oil phase, respectively. It was found that the interfacial tension was suppressed over the cathodic or anodic polarization range, depending on whether the surface active agent used was cationic or anionic, respectively. Here the sign of polarization was conventionally taken as that of the water phase with respect to the oil phase. It was then concluded by the use of theLippmann-Helmholtz equation that the water side of the interface is charged positively or negatively in the respective case mentioned above. It appears that this charge is due to the counter ion layer which is formed corresponding to the adsorption of ionic surface active agents on the oil side.

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Zusammenfassung Die Elektrokapillarität von Öl-Wasser-Grenzflächen mit Kaliumchlorid in den wässerigen und grenzflächenaktiven Ionen in der Ölphase wurde bei geringer Polarisation im Bereich von +20 V bis –20 V untersucht. Dabei wurde beobachtet, daß die Grenzflächenspannung durch kationische bzw. anionische Polarisation erniedrigt wurde, je nachdem, ob die grenzflächenaktiven Stoffe kationisch oder anionisch waren. Die Ergebnisse wurden mit Hilfe derLippmann-Helmholtz-Gleichung gedeutet. Es bildet sich eine elektrische Doppelschicht mit den grenzflächenaktiven Ionen an der Ölschicht und den anorganischen Gegenionen an der wässerigen Seite der Grenzfläche.

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With 10 figures and 2 tables     

The coalescence of mercury droplets in aqueous solutions in the presence of surface active materials

Colloid and Polymer Science - The range of the electrical potential of coalescence of mercury droplets in solutions of surface active materials was measured by using the twin dropping mercury...