A5046374024- Block Copolymer Self-Assembly
- Advanced Polymer Synthesis and Characterization
- Polymer Surface Interaction Studies
- Theoretical and Computational Physics
- Material Dynamics and Properties
- Surfactants and Colloidal Systems
- Polymer crystallization and properties
- Machine Learning in Materials Science
- Rheology and Fluid Dynamics Studies
- Liquid Crystal Research Advancements
- Electrostatics and Colloid Interactions
- Polymer Nanocomposites and Properties
- Nanopore and Nanochannel Transport Studies
- Lipid Membrane Structure and Behavior
- Supramolecular Self-Assembly in Materials
- Quasicrystal Structures and Properties
- Force Microscopy Techniques and Applications
- Fluid Dynamics and Thin Films
- Anodic Oxide Films and Nanostructures
- Dendrimers and Hyperbranched Polymers
- Advanced Physical and Chemical Molecular Interactions
- Pickering emulsions and particle stabilization
- Surface Modification and Superhydrophobicity
- Surface Chemistry and Catalysis
- Advanced Materials and Mechanics
McMaster University
2016-2025
Hangzhou Medical College
2024
Zhejiang Provincial People's Hospital
2024
Impact
2023
Fudan University
2010-2016
Nankai University
2005-2010
Ministry of Education and Child Care
2007-2009
Brockhouse Institute for Materials Research
2009
Zhejiang University
2009
Beijing National Laboratory for Molecular Sciences
2008
The stability of various spherical phases formed in conformationally asymmetric AB diblock and architecture ABm miktoarm block copolymers is investigated using self-consistent field theory. Both the conformational asymmetries are unified into a parameter degree, ε. We find that complex phase, σ becomes stable its phase region expands between bcc hexagonal as increasing Only for large asymmetry, example, ε = 9 (or m 3), A15 terminates at intermediate segregation region. Compared with has more...
Block copolymers are a class of soft matter that self-assemble to form ordered morphologies at nanometer scales, making them ideal materials for various applications. The self-assembly block is mainly controlled by the monomer–monomer interactions, compositions and molecular architectures. Besides these intrinsic parameters, placing under confinement introduces number extrinsic factors, including degree structural frustration surface–polymer which can strongly influence self-assembled...
The engineering of structures across different length scales is central to the design novel materials with controlled macroscopic properties. Herein, we introduce a unique class self-assembling materials, which are built upon shape- and volume-persistent molecular nanoparticles other structural motifs, such as polymers, can be viewed size-amplified version corresponding small-molecule counterparts. Among them, “giant surfactants” precise have been synthesized by “clicking” compact polar...
We explore the potential of nanocrystals (a term used equivalently to nanoparticles) as building blocks for nanomaterials, and current advances open challenges fundamental science developments applications. Nanocrystal assemblies are inherently multiscale, generation revolutionary material properties requires a precise understanding relationship between structure function, former being determined by classical effects latter often quantum effects. With an emphasis on theory computation, we...
Self-assembly of block copolymers confined in cylindrical nanopores is studied systematically using a simulated annealing technique. For diblock which form two-dimensional hexagonally packed cylinders with period L0 the bulk, novel structures such as helices and stacked toroids spontaneously inside pores. These confinement-induced morphologies have no counterpart bulk system they depend on pore diameter (D) surface-polymer interactions, reflecting importance structural frustration...
The metal atoms in the pyrochlore system of compounds (${\mathit{A}}_{2}$${\mathit{B}}_{2}$${\mathrm{O}}_{7}$, where A and B are metals) form an infinite three-dimensional network corner-sharing tetrahedra with cubic symmetry. For antiferromagnetic nearest-neighbor interactions only magnetic, there is a very high degree frustration, no long-range order predicted absence further neighbor interactions. general mean-field theory developed for dealing n-component classical vector spins on any...
Lamellar single crystals grown in dilute solutions can be used as templates for tethered chain analysis. Two series of diblock copolymers, poly(ethylene oxide)-block-polystyrene (PEO-b-PS) and poly(l-lactic acid)-block-polystyrene (PLLA-b-PS), were model to generate PS blocks on the single-crystal basal surfaces. Controlled tunable reduced tethering density, σ, defined by σπRg2 (where σ is density equal reciprocal covered area Rg radius gyration this its end-free state at same conditions),...
A novel, hierarchical morphology of budded mesoporous silica hollow spheres (see figure), comprising a wormholelike shell and protruding lamellar (vesicular) mesostructured buds, is fabricated by unique, single-step, emulsion-templating method in which the sodium salt N-lauroylsarcosine used as both surfactant an oil phase after acidification. Supporting information for this article available on WWW under http://www.wiley-vch.de/contents/jc_2089/2006/c1321_s.pdf or from author. Please note:...
Self-assembly of symmetric diblock copolymers confined in spherical nanopores is studied using simulated annealing Monte Carlo simulations. The dependence the self-assembled morphologies and chain conformations on degree confinement strength surface interactions examined systematically. A rich variety novel structures under three-dimensional has been revealed. As preference increased gradually from neutral to weakly preferential finally strongly one blocks, observed sequence stable...
The emergence of the complex Frank-Kasper phases from binary mixtures AB diblock copolymers is studied using self-consistent field theory. relative stability different ordered phases, including σ and A15 containing nonspherical minority domains with sizes, examined by a comparison their free energy. resulting phase diagrams reveal that occupies large region in space system. formation mechanism elucidated distribution two lengths compositions. In particular, segregation types copolymers,...
A generic Fourier-space approach to solve the self-consistent field theory of block copolymers is developed. This based on fact that, for any computational box with periodic boundary conditions, all spatially varying functions are spanned by Fourier series determined size and shape box. The method reproduces known diblock copolymer phases. application this a model ``frustrated'' triblock leads phase diagram number new Furthermore, capability reproduce experimentally observed structures...
Self-assembling block copolymers provide access to the fabrication of various ordered phases. In particular, spherical phases can be used engineer soft mesocrystals with domain size at 5-100 nm scales. Simple copolymers, such as diblock form a limited number mesocrystals. However multiblock are capable more complex We demonstrate that designed B1AB2CB3 terpolymers, in which A- and C-blocks domains packing these spheres controlled by changing lengths middle terminal B-blocks, self-assemble...
Cooling disordered compositionally asymmetric diblock copolymers leads to the formation of nearly spherical particles, each containing hundreds molecules, which crystallize upon cooling below order-disorder transition temperature (
Rafts, or functional domains, are transient nano- mesoscopic structures in the exoplasmic leaflet of plasma membrane, and thought to be essential for many cellular processes. Using neutron diffraction computer modelling, we present evidence existence highly ordered lipid domains cholesterol-rich (32.5 mol%) liquid-ordered () phase dipalmitoylphosphatidylcholine membranes. The liquid one-component membranes has previously been a homogeneous phase. presence embedded disordered matrix implies...
Among the various ordered morphologies self-assembled from block copolymers, spherical packing phases are particularly interesting because they resemble familiar atomic crystals. The commonly observed morphology of copolymers is body-centered-cubic phase. Recently, a number novel phases, i.e., complex Frank-Kasper originally obtained in metallic alloys, have been copolymer melts. Theoretical studies revealed that conformational asymmetry different blocks provides key mechanism to stabilize...
Superstretchable materials have many applications in advanced technological fields but are difficult to stretch more than 1000× their original length. A superstretchable dynamic polymer network that can be stretched 13 000× its length is designed. It revealed superstretchability of the derived from synergistic effect two different types bonds, including a small number strong imine bonds maintain integrity during stretching and large weak ionic hydrogen dissipate energy. This approach...
It is generally believed that the spherical domains self-assembled from AB-type block copolymers are composed of minority A blocks with a volume fraction fA < 1/2. Breaking this generic rule so formed by majority (fA > 1/2) requires mechanisms to drastically expand stable region packing phases. Self-consistent field theory predicts dendron-like copolymers, G - 1 generations connected outermost generation B blocks, exhibit phases extending ∼ 0.7. The extremely expanded regions shed light on...
The stability of the diblock copolymer ordered phases is investigated by means a novel theory anisotropic composition fluctuations. analogy between polymer chain in periodic structure and an electron crystalline solid exploited development theory. This allows calculation spinodal lines, most unstable modes, scattering functions phases. one-phase regions lamellar, cylindrical, spherical are found to be within their corresponding regions. On other hand, hexagonally-perforated lamellar phase...
The influence of polydispersity on the phase behavior diblock copolymer melts is studied using a self-consistent field theoretic model. A perturbation theory developed for polydisperse system, in which index, κ = Mw/Mn − 1, taken as parameter. Phase diagrams are constructed reciprocal space method. It found that order−disorder transition boundary shifts to higher temperatures, predicted by random approximation analysis. For asymmetric polymer distributions, favors structures with curved...
Using a variational argument, we show that two-dimensional (2D) crystal becomes defective in the presence of random potential. The threshold pinning force and flow properties plastically deformed are studied using perturbation theory valid for weak potential strong driving force. In case 2D flux-line lattice, it is shown dislocations introduce extra dissipation system, thus increasing total force, resulting nonlinear I-V characteristics.
The self-assembly of asymmetric diblock copolymers confined within cylindrical pores is studied using the self-consistent-field theory. cylinder-forming copolymer chosen to be near cylinder−gyroid phase boundary in intermediate segregation region. This choice makes self-assembled structure highly deformable, leading very rich morphologies under confinement. A variety structures, such as helices, stacked toroids, and perforated tubes, observed a function degree confinement characterized by...
Nucleation of various ordered phases in block copolymers is studied by examining the free-energy landscape within self-consistent field theory. The minimum energy path (MEP) connecting two computed using a recently developed string method. shape, size, and barrier critical nuclei are obtained from MEP, providing information about emergence stable phase metastable phase. In particular, structural evolution embryonic gyroid nucleus predicted to follow possible MEPs, revealing an interesting...
Self-assembly of cylinder-forming diblock copolymers under spherical confinement is studied using real-space self-consistent field theory calculations (SCFT). Various microstructures are found at different dimensions and surface fields. Most these center-symmetric they could not be formed in bulk or planar cylindrical confinements. It also observed that the interactions between polymers have a large effect on self-assembly. When confinement's attracts short blocks, self-assembled structures...
The self-assembly of diblock copolymers under soft confinement is studied systematically using a simulated annealing method applied to lattice model polymers. realized by the formation polymer droplets in poor solvent environment. Multiple sequences confinement-induced copolymer aggregates with different shapes and self-assembled internal morphologies are predicted as functions solvent-polymer interaction monomer concentration. It discovered that morphology largely controlled competition...
The phase behaviors of diblock copolymers confined in thin films with two identical preferential surfaces are investigated using the self-consistent field theory. Around 20 morphologies, including centrosymmetric and non-centrosymmetric ones, considered to construct two-dimensional diagram respect volume fraction film thickness, while interaction parameter χN surface preferences fixed. When these morphologies classified into four categories ordered phases--sphere, cylinder, perforated...