Collaborative Research: Understanding the Collective Effects in Suspensions of Vesicles, Capsules, and Particles

奖项：1066263 PI：Shaqfeh/MullerThis项目代表了对囊泡，胶囊和胶囊/颗粒混合物的个体动力学和集体相互作用的全面调查。这项合作研究是多相流现象的高性能计算机（HPC）模拟以及使用微流体和微流变学的详细实验之间的协同努力。新的方面的模拟算法包括一个光滑的粒子网格埃瓦尔德边界元代码采用频谱，循环细分，和边界元分辨率的变形和相互作用的接口。基本上，可以包括界面建模中的任意剪切、弯曲和伸缩模量，从而允许在复杂的微流体几何形状中模拟从胶囊到囊泡（包括刚性颗粒和混合物）的全范围动力学。此外，非布朗和布朗悬浮液可以模拟与高分辨率的界面。实验包括直接可视化，通过荧光显微镜，详细的囊泡随时间变化的动力学，并通过创造性的界面化学，在（a）微流体四辊磨机装置中具有变化剪切模量的胶囊（能够在滞流点附近再现任何平面混合流，在滞流点处囊泡/胶囊可以被捕获并观察延长的时间）和（B）微通道几何形状设计用于检查集体悬浮动力学。实验还将集中在测量，通过荧光显微镜和颗粒跟踪，剪切引起的颗粒扩散和流变行为的限制长度尺度是不同的。应用包括理解微循环中的血小板止血以及医学应用中的工程囊泡。

Award: 1066263PI: Shaqfeh/MullerThis project represents a comprehensive investigation of the individual dynamics and the collective interactions of vesicles, capsules, and capsule/particle mixtures. The collaborative research is a synergistic effort between high performance computer (HPC) simulations of multiphase flow phenomena as well as detailed experiments using microfluidics and microrheology. Novel aspects of the simulation algorithm include a smooth particle mesh Ewald boundary element code employing both spectral, Loop subdivision, and boundary element resolution of the deforming and interacting interfaces. Essentially, arbitrary shear, bending, and dilatational moduli in the interfacial modeling can be included thus allowing the full range of dynamics from capsules to vesicles including rigid particles and mixtures to be simulated in complex microfluidic geometries. Moreover, nonBrownian and Brownian suspensions can be simulated with high resolution of the interfaces. The experiments include direct visualization, via fluorescence microscopy, of the detailed time varying dynamics of vesicles, and, by creative interfacial chemistry, capsules with varying shear modulus in (a) the microfluidic four roll mill device (capable of reproducing any planar mixed flow in the vicinity of a stagnation point at which the vesicle/capsule may be trapped and observed for extended times) and (b) microchannel geometries designed for examination of collective suspension dynamics. Experiments will also focus on measurements, through fluorescence microscopy and particle tracking, of the shear-induced diffusion of particles and the rheological behavior as the confinement length scale is varied. Applications including understanding platelet hemostasis in the microcirculation as well as engineering vesicles for medical applications.