![]() ![]() Within the two-phase region, a polymer solution forms dense droplets with enriched solutes and a depleted dilute phase (2). At concentrations below saturation concentration ( C sat), the system is in the one-phase region (1). Phase separation starting from a homogeneous state (red dot) can be induced by increasing the concentration (Δ C > 0) or decreasing the temperature (Δ T < 0). At the critical point, the composition of the two liquid phases becomes identical, and the density difference between the phases approaches zero. The coexistence line (black curve) separates the one-phase region from the two-phase region on the phase diagram. b A phase diagram describes the phase behavior of macromolecular solutions as a function of concentration, influenced by various modulatory factors such as temperature and pH etc. Converging LCPS and LLPS has rarely been attempted in a synthetic system, although it would add a significant degree of tunability into LCPS if the physical triggers of LLPS, like temperature, were to be utilized in controlling their self-assembly behavior.Ī The volume-composition diagram illustrates two vertical lines at Onsager volume fractions \(\), corresponding to anisotropic colloidal particles with either one-phase or two-phase systems. Once the phase separation occurs, the formed liquid droplet compartments exhibit varying physical properties and assume different colloidal states, such as gel, glass, or crystals 19, 20, 21. LLPS is controlled by a phase equilibrium which depends on, e.g., temperature, pH and/or composition (Fig. By contrast, the underlying driving force of LLPS is the trade-off between enthalpy and entropy toward energy minimization, based on the interactions between different components 15, 16, 17. ![]() LCPS into upper isotropic and bottom ordered anisotropic phases is driven by the interplay between particle orientational entropy and excluded volume packing entropy, where the boundary conditions are governed by the aspect ratio of the particle (Fig. Furthermore, both of these two transitions can be mutually connected: in eucaryotic cells, for example, the membranes are formed by LCPS of lipid molecules whereas the nucleolus is condensed from LLPS of proteins 12, 13. ![]() In another realm, liquid-liquid phase separation (LLPS) in homogeneous macromolecular solutions is a prominent phenomenon in biological systems as it plays a dominant role in realizing cellular functions and creating subtle structures in living organisms 11. Specifically, dispersions of anisotropic particles undergo phase separation above the critical concentration 6, 7, 8, 9, termed as liquid crystal phase separation (LCPS) which has an immense potential in modern materials science with a wide range of applications 10. To minimize free energy, certain kind of colloids can demix into two coexisting phases to reach equilibrium 5. It can be triggered by different stimuli, occurring in a diverse range of natural and synthetic transition processes, including purification, compartmentation, and matter exchange 2, 3, 4. Phase separation is a persistently relevant topic that essentially entails order appearing from disorder in a heterogeneous system 1. Finally, upon drying, the multicomponent mixture undergoes a hierarchical self-assembly of nanocellulose and polymers into stratified cholesteric films, exhibiting compartmentalized polymer distribution and anisotropic microporous structure. Furthermore, a coupled multiphase transition can be realized by tuning the composition and the equilibrium temperature, which results in thermotropic behavior of polymers within a lyotropic liquid crystal matrix. Among which, each relevant multiphase separation kinetics shows fundamentally different paths governed by nucleation and growth of polymer droplets and nanocellulose tactoids. Upon thermodynamic control, two-, three-, and four-phase coexistence behaviors with rich liquid crystal stackings are realized. The phase behavior of the multicomponent mixture is controlled by the trade-off between thermodynamics and kinetics during the two transition processes, displaying cholesteric self-assembly of nanocellulose within or across the compartmented aqueous phases. In the current work, we develop a series of heterogeneous colloidal suspensions that exhibit both liquid-liquid phase separation of semiflexible binary polymers and liquid crystal phase separation of rigid, rod-like nanocellulose particles. Phase separation is a universal physical transition process whereby a homogeneous mixture splits into two distinct compartments that are driven by the component activity, elasticity, or compositions.
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