一些典型的软物质物理中的非平衡自组织现象

在软物质物理中经常有自组织(self-organization)现象发生.这一现象通常在非平衡的过程中产生,并生成非常美丽和有趣的图案与结构.具体例子包括胶体颗粒的扩散限制凝聚(diffusion limited aggregation,DLA),Hele-Shaw盒中产生的流体分形结构,凝胶的形成(gelation),生物体自组织聚集,以及颗粒类物质(granular material)运动产生的规则图案等.这些现象在软物质物理研究中产生了很多重要结果.文章以比较浅显的文字介绍这些软物质物理中的非平衡自组织现象.     

Self-diffusion in the isotropic and mesomorphic states of the lanthanide-containing system based on nonionic surfactant according to the NMR data

Molecular self-organization in a system based on lanthanum nitrate and the nonionogenic surfactant, viz., decaethylene glycol monododecyl ether, was studied in an aqueous solution and in the liquid-crystalline state. Molecular motion and phase transitions in the system were characterized by the high-resolution pulsed gradient spin-echo ¹H NMR method. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 488–494, March, 2008.     

液体基底表面金薄膜中的有序结构和自组装现象

研究了沉积在液体基底（硅油）表面金薄膜中的带状有序结构和自组装现象.实验结果表明：在一定条件下，生长在硅油表面的金薄膜中可形成一种特征的有序结构，它是由近似矩形状的畴块拼接而成的；相邻畴块的长度近似相等，但宽度一般不同，因而具有特征长度为101—102μm数量级的准周期结构.进一步的实验发现：此类带状有序结构是由薄膜中特征内应力所引起的物质相互挤压而形成的.另外，对此类具有近似自由支撑边界条件的薄膜中的内应力形成机理进行了研究. 关键词： 薄膜 有序结构 内应力 自组装     

Influence of a cationic polyelectrolyte on the inverse micellar region of the ternary system sulfobetaine/water/alcohol

The influence of the cationic polyelectrolyte poly(diallyldimethylammonium chloride) on structure formation in the inverse micellar region (L2 phase) of the ternary system 3 (N,N-dimethyldodecylammonio)propanesulfonate/alcohol/water has been investigated. Up to a polymer concentration in the aqueous phase of 10 wt %, an isotropic phase still exists. As the chain length of the alcohol component increases, the isotropic phase region is reduced and shifted in direction to the water corner. The isotropic polyelectrolyte-modified L2 phase of the heptanol-based microemulsion has been studied in much more detail by means of conductometric, rheological, and differential scanning calorimetry measurements. The polyelectrolyte-modified microemulsion phase shows a characteristic low shear viscosity and Newtonian flow behavior. The characteristic features of the nonpercolated microemulsion droplets are the low conductivity and the disappearance of bulk water. One can conclude from the experimental data that the individual nonpercolated polyelectrolyte-stuffed microemulsion droplets are approximately uniform in size. In addition, the area of the polyelectrolyte-modified inverse microemulsion phase with heptanol and octanol depends on the temperature. This means that the area of the L2 region can be increased by the temperature being increased from room temperature to 40 °C. This behavior can be explained by a change in the bending elasticity of the surface film induced by Coulombic interactions between the functional groups of the polyelectrolyte and the surfactant head groups. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 742–751, 2004     

Quasi-fluid state in gabbro

Usually, the matter state is divided into three kinds: solid state, fluid state and gas state. But under the normal temperature and pressure, the phenomenon of natural oscillation, similar to fluid property, happening on the surface of the solid-state materials, such as steel, Cu-Zn-Al alloy, and silicon single crystal, can be observed[1—3]. In the metal materials of the Cu-Zn-Al alloy and pure silver, the natural oscillation may lead to generation of alloy nanostructure as shown in fig. 1,…     

计入固液界面作用的润滑热力学模型与分析

摩擦与润滑过程是典型的能量耗散过程, 在机理上与非平衡热力学中的熵增、耗散结构等理论颇有相似之处. 通过热力学分析可以对一些典型的摩擦磨损过程做出合理的机理揭示与推测. 本文利用热力学理论对典型的润滑过程进行了建模分析. 采用分离压模型表征和计入了微尺度下的固液界面作用, 揭示分析了润滑热力学模型与润滑状态Stribeck曲线的联系. 从分析计算结果来看, 润滑Stribeck曲线的摩擦系数最低点与系统热力学上的熵增率最低点具有相当好的对应关系, 而润滑状态从弹流润滑向薄膜润滑的转变过程, 可以用耗散结构理论加以机理解释. 文中的热力学模型和方法能够有效地体现出润滑过程中多物理要素跨尺度非线性耦合的作用, 对实际工程与实验有着重要的指导作用.     

Solvent-induced self-organization approach for polymeric architectures of micropores,hexagons and spheres based on polyurethanes prepared via novel melt transurethane methodology

Solvent-induced self-organization approach was developed, for the first time, to produce polyurethane microporous templates and higher ordered morphologies such as micro or nanometer-sized polymeric hexagons and spheres. A novel melt transurethane methodology was designed and developed for synthesizing new class of cycloaliphatic polyurethanes under nonisocyanate and solvent-free conditions. In this new process, a diurethane monomer was polycondensed with equimolar amounts of diol in presence of Ti(OBu)₄ as catalyst with the removal of low boiling alcohol from the equilibrium. The hydrogen bonding of the polyurethanes are very unique to their chemical structure and they undergo selective phase-separation process in solution to produce hexagonally packed microporous templates. The increase of water content in the polymer solution enhances the phase-separation process and the micro pores coalesce to isolate the encapsulated polymer matrix into polymeric hexagons or densely packed solid spheres. The concentration-dependent solution FTIR and ¹H NMR of the polyurethanes revealed that the polymers possessing higher H-bonding association constants (K) have greater tendency to undergo solvent-induced self-organization phenomena. The mechanism of solvent-evaporation process indicated that only microporous polyurethanes have tendency to form higher ordered hexagons and spheres whereas others failed to show any new morphology. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2351–2366, 2007