起泡剂C_(12)E_8的表面流变学性质

Surface Rheological Properties of Foaming Agent C_(12)E_8

利用表面波技术研究起泡剂C_(12)E_8的表面流变学性质以及解释表面变形所产生的表面张力梯度的修复机理．实验结果表明，起泡剂C_(12)E_8的表面具有粘弹性质，其减胀模量与表面变形频率有关系．在低浓度时，随着溶液浓度的增加，表面吸附量的增加很高了膨胀模量．而在高浓度时，由于表面与溶液之间的扩散交换抵消了膨胀模量的增加，这导致膨胀模量随着溶液浓度增加反而降低．

The gravity draimage of foam leads to the dcforlllation of liquid film that results inthe surface tension gradients and the heterogencity of film thicknesses. The (deformation of liquidfilms causes the rupture of films. However, the deformation of liquid films produced from surfaceactive agents solution can be spontaneously restored by the 'Marangom effect'. This ability ofrestoration is connected with the surface rheology. The aim of this paper is to investigate thesurface rheology of foammg agent C_(12)E_8 by the (lamped longitudillal waves method and explamsthe restoration mechamsm of surface tension gradien due to the stretched surface. It is shown thatthe surface of foammg agent C_(12)E_8 is viscoclastic;and that the surface dilational modulus dependson the frequency of the perturbation,The increase of dilational modulus with concentrations at lower concentration is caused by the surface adsorption of molecules C12E8, while the decreasc athigher concentration is caused by bluk to surface diffusion exchange.