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Application of self-consistent field theory to self-assembled bilayer membranes

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Chinese Physics B 2015年第12期24卷 45-52页

作者：张平文史安昌 LMAM CAPT & School of Mathematical Sciences Peking University Department of Physics & Astronomy Mc Master University

Bilayer membranes self-assembled from amphiphilic molecules such as lipids, surfactants, and block copolymers are ubiquitous in biological and physiochemical systems. The shape and structure of bilayer membranes depend crucially on their mechanical properties such as surface tension, bending moduli, and line tension. Understanding how the molecular properties of the amphiphiles determine the structure and mechanics of the self-assembled bilayers requires a molecularly detailed theoretical framework. The self-consistent field theory provides such a theoretical framework, which is capable of accurately predicting the mechanical parameters of self-assembled bilayer membranes. In this mini review we summarize the formulation of the self-consistent field theory, as exemplified by a model system composed of flexible amphiphilic chains dissolved in hydrophilic polymeric solvents, and its application to the study of self-assembled bilayer membranes.

关键词： amphiphilic molecules bilayer membranes elastic moduli self-consistent field theory

An Efficient Algorithm for self-consistent field theory Calculations of Complex self-assembled Structures of Block Copolymer Melts

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Chinese Journal of Polymer Science 2018年第4期36卷 488-496页

作者： Jun-Qing Song Yi-Xin Liu Hong-Dong Zhang State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular Science Fudan University

self-consistent field theory（SCFT）, as a state-of-the-art technique for studying the self-assembly of block copolymers, is attracting continuous efforts to improve its accuracy and efficiency. Here we present a fourth-order exponential time differencing Runge-Kutta algorithm（ETDRK4） to solve the modified diffusion equation（MDE） which is the most time-consuming part of a SCFT calculation. By making a careful comparison with currently most efficient and popular algorithms, we demonstrate that the ETDRK4 algorithm significantly reduces the number of chain contour steps in solving the MDE, resulting in a boost of the overall computation efficiency, while it shares the same spatial accuracy with other algorithms. In addition, to demonstrate the power of our ETDRK4 algorithm, we apply it to compute the phase boundaries of the bicontinuous gyroid phase in the strong segregation regime and to verify the existence of the triple point of the O70 phase, the lamellar phase and the cylindrical phase.

关键词： Block copolymer self-consistent field theory Algorithm Pseudo-spectral Phase structure

Numerical Study of Two Opposing Weak Polyelectrolyte Brushes by the self-consistent field theory

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Chinese Journal of Polymer Science 2024年第11期42卷 1668-1678,I0007页

作者： Bei-Ning Wang Huan-Da Ding Zhi-Kuan Chen Chao-Hui Tong Department of Physics Ningbo UniversityNingbo315211China Ningbo Institute of Northwestern Polytechnical University Ningbo315103China

The self-consistent field theory(SCFT)was employed to numerically study the interaction and interpenetration between two opposing weak polyelectrolyte(PE)brushes formed by grafting weak PE chains onto the surfaces of two long and parallel columns with rectangularshaped cross-section immersed in a salty aqueous *** dependences of the brush heights and the average degree of ionization on various system parameters were also *** the brush separation is relatively large compared with the unperturbed brush height,the degree of interpenetration between the two opposing PE brushes was found to increase with increasing grafting density and bulk degree of *** degree of interpenetration also increases with the bulk salt concentration in the osmotic brush *** results further revealed that,at a brush separation comparable to the unperturbed brush height,the degree of interpenetration does not increase further with increasing bulk degree of ionization,bulk salt concentration in the osmotic regime and grafting *** saturation of the degree of interpenetration with these system parameters indicates that the grafted PE chains in the gap between the two columns retract and tilt in order to reduce the unfavorable electrostatic and steric repulsions between the two opposing PE *** on salt ion concentrations at the midpoint between the two opposing brushes,a quantitative criterion in terms of the unperturbed brush height and Debye screening length was established to determine the threshold value of the brush separation beyond which they are truly independent from each other.

关键词： Polyelectrolyte Polymer brush self-consistent field theory

Response of Bi-disperse Polyelectrolyte Brushes to External Electric fields A Numerical self-consistent field theory Study

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Chinese Journal of Polymer Science 2017年第1期35卷 98-107页

作者： Cong Kang Shuang-liang Zhao 童朝晖 Department of Physics Ningbo University Ningbo 315211 China College of Chemical Engineering East China University of Science and Technology Shanghai 200237 China

The self-consistent field theory has been employed to numerically study the response of bi-disperse flexible polyelectrolyte （PE） brushes grafted on an electrode to electric fields generated by opposite surface charges on the PE-grafted electrode and a second parallel electrode. The numerical study reveals that, under a positive external electric field, the shorter and negatively charged PE chains are more responsive than the longer PE chains in terms of the relative changes in their respective brush heights. Whereas under a negative external electric field, the opposite was observed. The total electric force on the grafted PE chains was calculated and it was found that, under a positive external electric field, the magnitude of the total electric force acting on one shorter PE chain is larger than that on one longer PE chain, or vice versa. The underlying mechanism was unraveled through analyzing the total electric field across the two oppositely charged electrodes.

关键词： Polyelectrolyte brushes self-consistent field theory Electrical stimulus Polydispersity

Transmembrane transport of multicomponent liposome-nanoparticles into giant vesicles

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Chinese Physics B 2022年第4期31卷 742-751页

作者： Hui-Fang Wang Chun-Rong Li Min-Na Sun Jun-Xing Pan Jin-Jun Zhang Department of Physics and Information Engineering Shanxi Normal UniversityTaiyuan 030000China Beijing Key Laboratory for Sensors Beijing Information Science&Technology UniversityBeijing 100192China Modern College of Humanities and Sciences of Shanxi Normal University Linfen 041004China

With the emergence and rapid development of nanotechnology,the nanoparticles hybridized with multicomponent lipids are more and more used in gene *** vectors interact with the cell membrane before entering into the ***,the nature of this interaction is important in investigating multicomponent liposome-nanoparticle(MLP)transport across the cell *** this paper the transport of MLPs across the membranes of giant vesicles(GVs)in solvents is studied by using the self-consistent field theory(SCFT).Based on the analysis of the MLP permeating the GV membranes,a simple transport model is *** effects of the difference in membrane morphology and the size of the nanoparticle on the endocytosis are discussed *** role of energy barriers in quasi-equilibrium is also *** results indicate that the interaction between MLP and GV is a spontaneous process and the energy barrier needs overcoming to form metastable *** results provide theoretical reference for better understanding the transmembrane transport process of nanoparticles,and guidance for relevant experimental studies as well.

关键词： multicomponent liposome-nanoparticles self-consistent field theory giant vesicles energy barrier

Controllable Nanostructural Transitions in Grafted Nanoparticle-Block Copolymer Composites

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Nano Research 2010年第5期3卷 356-362页

作者： Guang-Kui Xu Xi-Qiao Feng Shou-Wen Yu Institute of Biomechanics and Medical Engineering Department of Engineering MechanicsTsinghua UniversityBeijing 100084China

We report a theoretical investigation of self-assembled nanostructures of polymer-grafted nanoparticles in a block copolymer and explore underlying physical mechanisms by employing the self-consistent field method. By varying the particle concentration or the chain length and density of the grafted polymer, one can not only create various ordered morphologies (e.g., lamellar or hexagonally packed patterns) but also control the positions of nanoparticles either at the copolymer interfaces or in the center of one-block domains. The nanostructural transitions we here report are mainly attributed to the competition between entropy and enthalpy.

关键词： Block copolymer nanocomposite pattern formation self-assembly self-consistent field theory

Pair interaction of bilayer-coated nanoscopic particles

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Chinese Physics B 2009年第2期18卷 658-663页

作者：张启义 Department of Mathematics and Physics Chongqing University of Science and Technology

The pair interaction between bilayer membrane-coated nanosized particles has been explored by using the self- consistent field （SCF） theory. The bilayer membranes are composed of amphiphilic polymers. For different system parameters, the pair-interaction free energies are obtained. Particular emphasis is placed on the analysis of a sequence of structural transformations of bilayers on spherical particles, which occur during their approaching processes, For different head fractions of amphiphiles, the asymmetrical morphologies between bilayers on two particles and the inverted micellar intermediates have been found in the membrane fusion pathway. These results can benefit the fabrication of vesicles as encapsulation vectors for drug and gene delivery.

关键词： bilayer membrane inverted micellar intermediates nanoparticle self-consistent field theory

Supramolecular self-assembly Behaviors of Asymmetric Diblock Copolymer Blends with Hydrogen Bonding Interactions between Shorter Blocks Modelled by Yukawa Potentials

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Chinese Journal of Polymer Science 2021年第11期39卷 1502-1509页

作者： Xu Zhang Jialiang Chen Lin Xu Tianxi Liu Innovation Center for Textile Science and Technology State Key Laboratory for Modification of Chemical Fibers and Polymer MaterialsCollege of Materials Science and EngineeringDonghua UniversityShanghai 201620China National Garment and Accessories Quality Supervision Testing Center(Fujian) Fujian Provincial Key Laboratory of Textiles Inspection TechnologyFujian Fiber Inspection CenterFuzhou 350026China Key Laboratory of Synthetic and Biological Colloids Ministry of EducationSchool of Chemical and Material EngineeringJiangnan UniversityWuxi 214122China

We employed the extended self-consistent field theory to investigate the supramolecular self-assembly behaviors of asymmetric diblock copolymer blends(AB/B’C)with hydrogen bonding interactions between shorter B and B’*** hydrogen bonding interactions are described by Yukawa potentials,where the hydrogen bonding donors and acceptors were modelled as two blocks smeared with opposite screened *** hierarchical microstructures with parallelly packed lamellae-in-lamellae(Lam)and 4.8.8 Archimedean tilting pattern(4.8.8)were observed at lower and higher hydrogen bonding density(θ),*** hierarchy of Lam and 4.8.8 were demonstrated by the one-and two-dimensional density profiles and the underlying order of the large-length-scale and small-length-scale microstructures were also *** was found that the 4.8.8 is favorable to the stronger hydrogen bonding density or ***θincreases,the microphase transition from Lam to 4.8.8 occurs atθ=0.34,which is mainly attributed to the optimization of the electrostatic energy and conformational entropy with sacrificing the interfacial *** work can provide a new strategy to understand the supramolecular self-assembly as well as the mechanism behind the formation of complex hierarchical microstructures.

关键词： Supramolecular self-assembly Hydrogen bond Block copolymer self-consistent field theory Hierarchical microstructure

Structures and Surface States of Polymer Brushes in Good Solvents:Effects of Surface Interactions

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Chinese Journal of Polymer Science 2018年第9期36卷 1047-1054页

作者： Yi-Xin Liu Hong-Dong Zhang State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular Science Fudan University

The influence of the surface interaction on the mesoscopic structure of grafted polymers in good solvents has been examined. At high surface coverage, tethered polymers are in the brush state and the parabolic segment density profile is confirmed by self-consistent field theory （SCFT） calculations. It is found that this is a universal behavior for a whole range of surface interactions from complete repulsion to strong attraction. More interestingly, finite surface repulsion may lead to the maximum in the proximal layer of its segment density profile, which is significantly different from both the depletion layer of pure repulsion and the adsorbing layer of attraction. In addition to the brush state on both repulsive and attractive surfaces, three additional surface states were identified by analyzing the scaling behavior of the layer thickness of polymer brushes： the mushroom state on repulsive substrates, the dilute and the semidilute surface states on attractive substrates.

关键词： self-consistent field theory Scaling theory Polymer thin film Polymer brush