在光敏性三元聚合物混合物中构造 多尺度有序图案

由多组分聚合物混合物所形成的多尺度有序结构能够展现出许多新奇的物理化学性质, 从而使其在材料工程领域具有十分重要的潜 在应用价值. 本文通过计算机模拟, 在光敏性不相容三元混合物体系中创建了多尺度有序结构. 通过调节光照区域和掩膜形状, 获得了棋盘形、箭靶状等十分独特的形貌, 并且这些结构可以在实验上通过在适当的时间淬火而稳定较长的时间. 详细探讨了组分比、掩膜宽度、间距以及光照强度对体系的影响, 从而为实现多尺度长程序花样薄膜的制备提供了一个简便的途径, 同时也为纳米器件的制备提供了一定的指导.     

Phase behaviors in a binary mixture of diblock copolymers confined between two parallel walls

The phase behaviors in a binary mixture of diblock copolymers confined between two parallel walls are investigated by using a cell dynamics simulation of the time-dependent Ginzburg-Landau theory.The morphological dependence of the wall-block interaction and the distance between walls(confinement degree) has been systematically studied,and the effect of repulsive interactions between different monomers is also discussed.It is interesting that multiple novel morphological transitions are observed by changing these factors,and various multilayered sandwich structures are formed in the mixture.Furthermore,the parametric dependence and physical reasons for the microdomain growth and orientational order transitions are discussed.From the simulation,we find that much richer morphologies can form in a binary mixture of diblock copolymers than those in a pure diblock copolymer.Our results provide an insight into the phase behaviors under parallel wall confinement and may provide guidance for experimentalists.This model system can also give a simple way to realize orientational order transition in soft materials through confinement.     

Copolymer-homopolymer mixtures in a nanopore

We have performed the cell dynamics simulation with the time-dependent Ginzburg-Landau theory to study the selfassembled morphology of A-B diblock copolymers and C homopolymers in a neutral nanopore. The nanopore diameter and length are systematically varied to examine their effects on the structures of various morphologies and their phase transition. From the simulation, it is observed that the equilibrium morphology of the confined system is sensitive to pore diameter D and pore length Lpore , the phase behavior in neutral nanopores is due to an interplay of two factors: the surface effect and the extension effect. When the nanopore length and the lamellae spacing are not commensurate, the surface effect prevails at small nanopores (small diameters or short lengths), the extension effect takes over at larger nanopores (large diameters or long lengths). When the nanopore length and the lamellae spacing are commensurate, the surface effect dominates. Furthermore, the interactions between different monomers are also discussed and we obtain a transition from a tilted pancakes/cylinder structure (L⊥tilted ) to a concentric cylindrical structure with defects and to a concentric cylindrical structure (L|| ). We also investigate the effect of the relative concentrations of diblock copolymer-homopolymer and obtain a transition in which the position of the C blocks changes from the outer of the cylinder to the middle of the cylinder and then to the inner of the cylinder with the concentration of the C blocks decreasing.     

伪二元函数的Hermite插值

将一元函数的Hermite插值方法与伪二元函数结合,得到了伪二元函数的Hermite插值函数,并对插值函数进行了误差分析,最后给出了一个实例.     

Observational constraints on running vacuum model

We investigate the power spectra of the CMB temperature and matter density in the running vacuum model(RVM) with the time-dependent cosmological constant of A=3 vH~2+ Λ_0, where H is the Hubble parameter. In this model, dark energy decreases in time and decays to both matter and radiation. By using the Markov chain Monte Carlo method, we constrain the model parameter v as well as the cosmological observables. Explicitly, we obtain v ≤1.54× 10~(-4)(68% confidence level) in the RVM with the best-fit χ_(RVM)~2 =13968.8, which is slightly smaller thanχ_(ΛCDM)~2= 13969.8 in the ΛCDM model of v = 0.     

Phase transition of a diblock copolymer and homopolymer hybrid system induced by different properties of nanorods

We investigated phase transitions in a diblock copolymer–homopolymer hybrid system blended with nanorods(NRs)by using the time-dependent Ginzburg–Landau theory. We systematically studied the effects of the number, length and infiltration properties of the NRs on the self-assembly of the composites and the phase transitions occurring in the material.An analysis of the phase diagram was carried out to obtain the formation conditions of sea island structure nanorodbased aggregate, sea island structure nanorod-based dispersion, lamellar structure nanorod-based multilayer arrangement and nanowire structure. Further analysis of the evolution of the domain sizes and the distribution of the nanorod angle microphase structure was performed. Our simulation provides theoretical guidance for the preparation of ordered nanowire structures and a reference to improve the function of a polymer nanocomposite material.     

纳米粒子驱动受限环境下两嵌段共聚物/均聚物混合体系的自组装行为

采用含时金兹堡-朗道理论(time-dependent ginzburg-landau theory,简称TDGL)方法研究了纳米粒子(nanoparticles,简称NPs)掺杂的两嵌段共聚物/均聚物(AB/C)共混体系在球形受限下的自组装行为.在不同球形受限条件下,两嵌段共聚物/均聚物共混体系形成了多种丰富的形貌,如双螺旋结构、单螺旋结构、层状结构和洋葱环状结构等.当在以上前3种体系中掺杂纳米粒子后,体系结构发生了很大的变化.详细研究了纳米粒子的浓度和浸润强度对以上结构的影响.研究结果表明,通过调控纳米粒子的浓度和浸润性质,该共混体系实现了双螺旋结构→层状结构,单螺旋结构→双螺旋结构,层状结构→单螺旋结构等多种取向序的转变.对于洋葱环状结构,纳米粒子的加入对体系这一结构的影响不大.     

Transmembrane transport of multicomponent liposome-nanoparticles into giant vesicles

With the emergence and rapid development of nanotechnology, the nanoparticles hybridized with multicomponent lipids are more and more used in gene delivery. These vectors interact with the cell membrane before entering into the cell. Therefore, the nature of this interaction is important in investigating multicomponent liposome-nanoparticle (MLP) transport across the cell membrane. In 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 proposed. The effects of the difference in membrane morphology and the size of the nanoparticle on the endocytosis are discussed systematically. The role of energy barriers in quasi-equilibrium is also examined. The results indicate that the interaction between MLP and GV is a spontaneous process and the energy barrier needs overcoming to form metastable intermediates. The results provide theoretical reference for better understanding the transmembrane transport process of nanoparticles, and guidance for relevant experimental studies as well.     

脂质体-纳米粒与单个巨型囊泡相互作用的理论模拟

采用自洽平均场方法模拟了脂质体-纳米粒与巨型囊泡的相互作用.在初始状态,脂质体-纳米粒与巨型囊泡之间有一定距离,随着距离的变化,脂质体-纳米粒与囊泡发生相互作用,最终脂质体小囊泡和巨型囊泡会融合并使粒子释放.随着囊泡的磷脂分子组分的变化,体系呈现出丰富的结构变化.磷脂头体积分数较大时体系形成融合通道(stalk相)或半融合隔膜(HD相)以及融合小孔;磷脂头体积分数较小时体系出现囊泡的渗漏形成亲水聚集体(棒状HII相或IMI相)和融合小孔.改变了所包裹的纳米粒半径,发现对体系的结构影响不大.我们定量的计算了各个体系的自由能,从自由能分析可知,随着距离的减小,脂质体-纳米粒与巨型囊泡相互作用的过程是一个自发过程.在相互作用过程中,新结构的形成需要克服能量壁垒,且能量壁垒随着磷脂头体积分数和纳米粒半径的增大都会有一定程度的增加.