| The multiphase and multicomponent liquid processing has been widely applied in the fabrication of soft matter,such as the systems of dynamic reaction,drug storage and release,substance transfer and separation,additive manufacturing and artificial cells designing among others.The curvature regulation of the liquid/liquid interface,therein,plays an extremely significant role in its processing procedure,determining the design of each hierarchical structure and final performance of the composite systems.Nevertheless,it becomes a grand challenge to accurately regulate the curvature of the liquid/liquid interface during the processing due to the complexity of multiphase and multicomponent liquid systems and the difficulty in synergistic regulation of the phases/components.For example,the high Laplace pressure(ΔP=γ/h,γ and h respectively represent the interfacial tension and thickness of liquid film)makes it difficult to obtain the zero-curvature liquid film during the coating process of ultra-thin liquid film.Another example is that the interfacial tension of the aqueous two-phase systems(ATPS)is extremely low(<0.1 mN m-1),making it intractable to precisely regulate the curvature of the two-phase interface in these systems.In this paper,the curvature of liquid/liquid interface is regulated by the synergistic action of polymers and otherwise components in the multiphase and multicomponent liquid systems around the above key challenge,realizing the manipulation of zero curvature for the hightension interface and positive/negative curvature at a wide range for the extremely lowtension interface.Firstly,the kinetics of synergistic assembly and the mechanical property of the assemblies are regulated by the interfacial co-assembly between polymers and nanoparticles(NPs),which are utilized to resist the Laplace pressure at oil/water interface and obtain the zero-curvature liquid film,and further achieving the preparation of uniform polymer coating.Secondly,the interfacial evolution of ATPS droplets on the superamphiphobic surface is regulated by the synergistic action between different polymers,so that the positive and negative curvature of aqueous/aqueous interface is accurately adjusted in a large range,and realizing the preparation of Janus particles with controllable interfacial curvature and Janus balance.The details are as follows:(1)The PDMS-NH2-CNC-OSO3H(PCNC)assemblies are formed at the oil/water interface by the electrostatic interactions between amino-functionalized polydimethylsiloxane(PDMS-NH2)dissolved in the oil phase and sulfonated cellulose nanocrystals(CNC-OSO3H)dispersed in the aqueous phase.The packing density of these assemblies are controlled by the assembly conditions,and the conditions of high concentration with low molecular weight of PDMS-NH2(≥ 1 mM,1k),as well as the high concentration of CNC with relatively low aqueous pH(≥ 10 mg mL-1,pH 2.00)promote their rapid co-assemblies to form a dense and rigid PCNC monolayer at the interface.When the interfacial area of liquid reduces,the nonequilibrium interface of which can be stabilized by the jamming of these assemblies.(2)The coaxial drawing fiber fluid coating method is developed,that is,the liquid film of oil phase on the fiber is coated in the aqueous phase.Based on the interfacial co-assembly of PDMS-NH2 and CNC-OSO3H in(1),as well as optimizing and selecting the assembly parameters such as PDMS-NH2(1 mM,1k)in the oil phase and CNC in the aqueous phase(10 mg mL-1,pH 2.00),the zero-curvature polymer liquid film(the curvature for the liquid film at the radial direction of the fiber is 0)on the fiber surface is obtained.The quantitative relationship,i.e.,h=3.01R(ηV/γ)2/3,between the polymer liquid film thickness(h)and the coating parameters,including the fiber drawing velocity(V),fiber radius(R),oil/water interfacial tension(γ)and polymer solution viscosity(η),is established,and guiding the preparation of polymer coating with the controllable thickness(50 nm-12 μm).And,the polymer coating with anti-oxidant function was prepared on the surface of copper fiber.(3)The liquid/liquid interface with tunable positive and negative curvature is another kind of system for multiphase and multicomponent liquid processing.By virtue of the superamphiphobic surface,the typical polyethylene glycol(PEG)/dextran(DEX)aqueous solutions are used to form ATPS droplets.The phase diagram related with the molecular weights and concentrations of PEG and DEX is drawn,and the relationship between this phase diagram and morphological structure of ATPS droplets(curvature of the aqueous/aqueous interface and volume ratio between the two phases)is established.By synergistically adjusting the molecular weights and concentration of the two polymers in ATPS droplets,the transition from positive to negative(the convex is positive while the concave is negative)and precise manipulation at a wide range(-0.64-1.99 mm-1)for the curvature of aqueous/aqueous interface is realized.(4)Based on the thermodynamic relationship between the phase diagram of concentration of PEG/DEX and the interfacial curvature of the ATPS droplets in(3),the ATPS droplets are induced from a single initial state to a variety of final states via the volatilization,and the motion trajectory of components in which on the phase diagram is controlled,further realizing the dynamic manipulation of the morphology of ATPS droplets.And,the effect of hydrophobicity of the substrates on the evolution of droplet phase interface is revealed.The Janus hydrogels and particles with adjustable interfacial curvature(0.44-1.43mm-1)were prepared via introducing the hydrogel monomers,crosslinkers,photoinitiators and/or NPs in the fixed phases on the basis of non-effect for the phase behavior and interfacial evolution of ATPS droplets.In addition,the phase behavior of ATPS solution is mainly controlled by the synergistic action between two different polymer chains,and the interfacial evolution in its droplet is not affected by the system pH. |
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