Collaborative Research: Reversible and Triggerable Self-Assembly of Photoresponsive Catanionic Vesicles

Cbet-0829209 Lee当一种液体在固体表面置换另一种液体时，它与固体的夹角称为动态接触角。它提供了对固体作用力的测量，并被用来了解工艺可行性的极限。当被驱替的流体被夹带时，就会出现这个极限。这些特征可以在涂布流动中观察到，就像在照相胶片制作中一样，在孔隙中一种流体被另一种流体置换，这在通过与另一种流体置换来回收原油方面具有重要意义，以及在微电子设备中观察到，其中连续的液体或液体池从一个区域移动到另一个区域。智力上的功绩。在这里提出的建模研究中，P.I.将在早期成功的模型之后，将接触线区域近似为该动态接触角的液体楔体，以取代第二个流体。将动量平衡方程按Re，(雷诺数)的顺序正确求解，并计算整个系统的粘性耗散。这等同于表面做功的速度，同样遵循较早的成功模型。最终的解将以角度的形式作为Ca、(毛细管数)和Re的函数。新的特征是：(A)将建立大角度的关联，(B)将建立液-液系统的关联，(C)在夹角=180°(或0°)处的夹带开始，并将确定系统几何形状不同的原因。在不同的公式下，还将分别研究一个更简单的问题，即在后退接触线中的卷吸问题。P.I.还将进行实验，以获得上述系统和操作范围的实验数据。更广泛的影响。这些结果将允许人们在涂层工艺可行的情况下设置操作窗口，假设该工艺在夹带时失败。动态接触角还提供了系统中力平衡的估计值。因此，上述相关性为处于新兴技术前沿的系统中的合理工艺设计提供了非常好的基础。基本理论是直截了当的，所取得的进展也可以纳入到教学中，要么是界面现象课程，要么是输运课程，这两门课程都是由P.I.以技术选修课的形式教授的。本科生和研究生都将在实验室工作。

CBET-0829209 LeeWhen a liquid displaces another fluid on a solid surface, the angle that it subtends with the solid is called the dynamic contact angle. It provides a measure of the force on the solid and is used to understand the limits of the feasibility of the process. This limit arises when the displaced fluid gets entrained. These features are observed in coating flows as in making of photographic films, in displacement of one fluid by another in a pore which is of importance in the recovery of crude petroleum oil by displacement with another fluid, and in microelectronic devices where pools of liquid or liquid in a continuous form is moved from one region to another. Intellectual Merit. In the modeling studies proposed here, the P.I. will approximate the contact line region a liquid wedge of this dynamic contact angle displacing a second fluid following earlier successful models. The momentum balance equations will be solved correct to order of Re,(Reynolds number) and viscous dissipation will be calculated for the whole system. This is equated to the rate of surface work done, again following earlier successful model. Final solution will be in the form of the angle as a function of Ca, (capillary number) and Re. The novel features are (a) correlations at large the angle will be established, (b) correlations for liquid-liquid system will be established (c) the onset of entrainment at the angle = 180° (or at 0°), and the reasons why it may vary from one system geometry to another will be established. A simpler problem of entrainment in a receding contact line will also be studied separately under a different formulation. The P.I. will also perform experiments to obtain experimental data for the above systems and ranges of operation. Broader Impact. These results would allow one to set windows of operation where a coating process is feasible, assuming that the process fails at entrainment. Dynamic contact angles also provide estimates of force balances in the systems. Consequently, the above correlations provide a very good basis for sound process design in systems that are in the cutting edge in emerging technologies. The basic theory is straightforward and the progress that would be made can also be incorporated into teaching either in a course on interfacial phenomena or transport, both of which are taught by the P.I. in form of technical electives. Both undergraduates and graduate students will be employed in the laboratory.