论文标题

从异质胶体系统中的热力学分解动力学

Disentangling kinetics from thermodynamics in heterogeneous colloidal systems

论文作者

Almohammadi, Hamed, Martinek, Sandra, Yuan, Ye, Fischer, Peter, Mezzenga, Raffaele

论文摘要

成核和生长(N&G) - 最初均匀阶段的新阶段的出现 - 是气体液体,液体液体和固体液相分离的最重要的物理现象之一。因此,热力学设定了系统必须发展的渐近边界,而动力学试图通过强加实现相位分离的传输速率来应对它。在自然界观察到的所有异质胶体系统中,组成,形状,结构以及最终是由热力学和动力学之间的权衡而产生的。在这项工作中,我们通过仔细选择胶体系统并控制微流体设备中的相位分​​离,表明可以超越N&G,从而使动力学从热力学效应从热力学效应中造成最终系统的组成,结构和物理性质的影响。使用两条单​​独的垂直线给出了使用淀粉样纤维和纤维素纳米晶体丝状胶体胶体,该曲线定义了相图中的两相区域,我们通过两个单独的垂直线给出了一个溶液,在另一个分支内的一个热力学分支中挤出了一个溶液,该溶液在另一个分支内部,通过胆汁液体或胆小性液滴来实现组成部分,而该液体是由热量组成的,同时是由热力学组成的,而参数是在热力学上设置的,同时又有杂物。我们证明,偏离N&G范式揭示了新的物理现象,例如较短的时间尺度,更宽的相图和内部胆固醇结构,这些结构无法通过常规LLP可观察到。我们还表明,通过在胶体液晶液滴中共同分散等离子金纳米颗粒,我们的方法可以在多组分结构液中对多组分异质液晶的需求制造,增强其潜力并引入原始的基本和技术指导。

Nucleation and growth (N&G) - the emergence of a new phase within an initially homogeneous one - is one of the most important physical phenomena by which gas-liquid, liquid-liquid and solid-liquid phase separation takes place. Accordingly, thermodynamics sets the asymptotic boundaries towards which the system must evolve, while kinetics tries to cope with it by imposing the transport rates at which phase separation is realized. In all heterogeneous colloidal systems observed in nature, the composition, shape, structure and ultimately physical properties result from the trade-off between thermodynamics and kinetics. In this work we demonstrate, by carefully selecting colloidal systems and controlling phase separation in microfluidic devices, that it becomes possible to go beyond N&G, disentangling kinetics effects from thermodynamics in composition, structure and physical properties of the final system. Using amyloid fibril and cellulose nanocrystal filamentous colloids for which the binodal curve defining the two-phase region in the phase diagram is given by two separate vertical lines, we extrude a solution set at one thermodynamic branch inside the other branch, realizing nematic or cholesteric droplets where the composition is set by thermodynamics, while the structure and morphology are defined by dynamic flow parameters. We demonstrate that departing from the N&G paradigm unveils new physical phenomena, such as orders of magnitude shorter timescales, a wider phase diagram and internal cholesteric structures that are not observable via conventional LLPS. We also show that by co-dispersing plasmonic gold nanoparticles within colloidal liquid crystalline droplets, our approach enables on-demand fabrication of multicomponent heterogeneous liquid crystals, enhancing their potential, and introducing original fundamental and technological directions in multicomponent structured fluids.

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