用溶致液晶模板合成与组装纳米材料*

总结了溶致液晶作模板合成与组装纳米材料的各种方法,特别分析了近来兴起的以溶致液晶为构建支架,以纳米粒子为构建单元制备无机/有机杂合体的特点,并对未来发展趋势作了展望.     

仿生溶致液晶体系的构建与掺杂

本文综述了以类脂为基础的仿生溶致液晶体系的构建与掺杂，对掺杂物质与液晶模板之间的相互作用进行了分析，并展望了仿生溶致液晶体系在合成新型功能材料、生物学和医学等领域应用的发展前景。     

手性模板合成CdS纳米棒

由于纳米材料具有量子尺寸效应及大的比表面积等性质而使其在电子学[1]、光学[2]、催化[3]和陶瓷[4]等领域显示出诱人的应用前景. 近年来纳米材料的制备及纳米技术发展迅速, 特别是具有特殊光电活性的新型无机纳米材料的制备已引起人们的普遍关注. 现在合成纳米材料的方法主要包括反相胶束法[5]、 LB膜法[6]、嵌段共聚物法[7]和模板合成法[8]. 其中模板合成技术不仅可以通过设计新型的模板分子, 还可通过模板分子的不同自组装行为来调控纳米材料的尺寸和形貌. Stupp等[9]曾利用溶致液晶的六方中间相作为模板, 在其纳米孔隙中成功地合成了具有六方排列超晶格纳米结构的材料. 本文以双亲性丙氨酸衍生物为模板, 在不同的化学微环境下合成了结构不同的CdS纳米棒.     

苯炔体系大环合成、自组装及其应用

含苯炔结构的大环(aryleneethynylenemacrocycle,AEMs)体系具有独特的性质和潜在的应用前景,在过去的数年中被广泛研究和探索。本文系统地介绍了AEMs的合成方法,包括不同关环方法、固相合成、模板合成和聚集驱动关环法等。在研究AEMs性质方面,重点介绍了它们的自组装性能。同时也介绍了AEMs在构造三维纳米结构、液晶、管状通道、主客体复合物等超分子化学领域的应用。     

纤维素及其衍生物液晶研究新进展

本文全面地综述了纤维素及其衍生物溶致性液晶和热致性液晶的形成, 液晶性与大分子链结构, 以及具有胆甾型液晶相结构的纤维素衍生物复合材料等方面的最新研究进展。     

苯炔体系大环合成、自组装及其应用

含苯炔结构的大环(arylene ethynylene macrocycle,AEMs)体系具有独特的性质和潜在的应用前景,在过去的数年中被广泛研究和探索.本文系统地介绍了AEMs的合成方法,包括不同关环方法、固相合成、模板合成和聚集驱动关环法等.在研究AEMs性质方面,重点介绍了它们的自组装性能.同时也介绍了AEMs在构造三维纳米结构、液晶、管状通道、主客体复合物等超分子化学领域的应用.     

溶致液晶模板电化学沉积纳米材料

本文综述了以小分子表面活性剂构成的溶致液晶作模板,采用电沉积方法制备金属、半导体、导电聚合物的纳米膜、纳米线等材料的研究进展.对影响沉积产物形貌和性能的各因素进行了分析,展望了溶致液晶模板电沉积纳米材料的发展趋势.     

以液晶高分子为结构导向设计与合成新型分子筛

利用液晶的有序结构为模板可以制备出性能优异的新型分子筛。综述了双亲分子液晶模板合成分子筛的优缺点,展望了以高分子液晶为模板在分子筛合成与修饰方面的潜力,并预见了以高分子液晶为模板仿生合成具有新型结构分子筛的广阔前景。     

聚己内酯分子量对乙基纤维素/聚己内酯共混体系的溶致性液晶织构的影响

利用偏光显微镜研究了乙基纤维素与聚己内酯共混物在二氯乙酸中的溶致性液晶形态。结果表明聚己内酯的分子量对共混体系的溶致性液晶结构有明显的影响。差示扫描量法测试显示含不同分子量聚己内酯的共混物,其混溶性及两组分间的相互作用无十分明显的差异。聚内酯分子量对共混体系溶致性液晶的形态和热稳定性的影响,可认为是由于分子量对体系的粘度贡献引起的。     

层状溶致液晶中Ag纳米粒子的掺杂

通过在具有长程有序结构的有机溶致液晶内嵌入预制的、表面性质可调控的银纳米粒子, 得到了亲水与亲油介观空间内同时嵌入纳米粒子的无机/有机杂合体. 掺杂前后液晶结构的变化和杂合体稳定性用小角X射线散射和偏振光学显微镜等进行了表征. 结果表明, 表面活性剂双层膜与导入纳米粒子间的立体化学匹配及相互作用是影响杂合体稳定性的重要因素.     

Ordered 2-D and 3-D nanostructured amphiphile self-assembly materials stable in excess solvent

Amphiphile lyotropic liquid crystalline self-assembly materials are being used for a diverse range of applications. Historically, the most studied lyotropic liquid crystalline phase is probably the one-dimensional (1-D) lamellar phase, which has been employed as a model system for biomembranes and for drug delivery applications. In recent years, the structurally more complex 2-D and 3-D ordered lyotropic liquid crystalline phases, of which reversed hexagonal (H(2)) and reversed cubic phases (v(2)) are two prominent examples, have received growing interest. As is the case for the lamellar phase, these phases are frequently stable in excess water, which facilitates the preparation of nanoparticle dispersions and makes them suitable candidates for the encapsulation and controlled release of drugs. Integral membrane protein crystallization media and templates for the synthesis of inorganic nanostructured materials are other applications for 2-D and 3-D amphiphile self-assembly materials. The number of amphiphiles identified as forming nanostructured reversed phases stable in excess solvent is rapidly growing. In this article, different classes of amphiphiles that form reversed phases in excess solvent are reviewed, with an emphasis on linking phase behavior to amphiphile structure. The different amphiphile classes include: ethylene oxide-, monoacylglycerol-, glycolipid-, phosphatidylethanolamine-, and urea-based amphiphiles.     

Electrochemical synthesis of nanostructured tellurium films

Direct templating of materials via lyotropic liquid crystalline mesophases of non-ionic surfactants provides an elegant and highly versatile route to the production of a wide range of nanostructured materials with well-defined mesoporous architectures of extended spatial periodicities. This technique has now been applied in the electrochemical synthesis of adherent nanostructured tellurium films. This represents an important step towards the synthesis of II–IV semiconductor compounds such as cadmium telluride. Low angle X-ray scattering and transmission electron microscopy (TEM) studies of the resulting tellurium films indicate the presence of a system of uniform cylindrical pores organized in an hexagonal array.     

Liquid crystal templating of nanomaterials with nature's toolbox

Naturally occurring biomolecules are sustainable and green precursors for the development of new materials. Within this family of natural materials, cellulose nanocrystals (CNCs) have emerged as one of the most promising materials because of their outstanding physico-chemical properties and the possibility to produce them in large quantities. One key trait of CNCs is their ability to self-assemble into a chiral nematic liquid crystalline phase. In this review, we discuss how templating can be used to transfer the three-dimensional structure of liquid crystalline CNC phases onto solid materials. This is followed by examples that illustrate the fascinating properties and potential applications that arise from the resulting nanostructured materials such as sensing and catalysis. We then summarize efforts to use the liquid crystalline phase of a selection of other biopolymers for templating. While nanocrystalline chitin, having very similar properties to CNCs, has been successfully employed to make a variety of new materials, efforts to template liquid crystal phases of other biomolecules have been met with limited success. However, we discuss virus nanoparticles and collagen as examples to highlight further possibilities for materials research.     

Polymerization of and within self-organized media

Self-organized surfactant solutions, such as microemulsions, vesicular solutions or dispersions, or lyotropic mesophases can serve as templates for the structure directed synthesis of organic polymers. Recent developments of templating within these equilibrium nanostructured fluids are reviewed. Depending on the template structure and the reaction conditions, the outcomes may be polyampholytes, amphiphiles, nanoparticles, hollow spheres, or mesoporous polymers. For each structure and morphology, the final product materials reflect a delicate balance between phase behavior and the reaction and mass transfer parameters that set structure. Experimental and theoretical aspects of reaction kinetics and thermodynamics such as monomer partitioning, swelling behavior and polymerization-induced phase separation are discussed.     

Templating hydrogels

Templating processes for creating polymerized hydrogels are reviewed. The use of contact photonic crystals and of non-contact colloidal crystalline arrays as templates are described and applications to chemical sensing and device fabrication are illustrated. Emulsion templating is illustrated in the formation of microporous membranes, and templating on reverse emulsions and double emulsions is described. Templating in solutions of macromolecules and micelles is discussed and then various applications of hydrogel templating on surfactant liquid crystalline mesophases are illustrated, including a nanoscale analogue of colloidal crystalline array templating, except that the bead array in this case is a cubic array of nonionic micelles. The use of particles as templates in making core-shell and hollow microgel beads is described, as is the use of membrane pores as another illustration of confinement templating.     

Biomimetic Synthesis of Shaped and Chiral Silica Entities Templated by Organic Objective Materials

Organic molecules with accompanying self‐organization have been a great subject in chemistry, material science and nanotechnology in the past two decades. One of the most important roles of organized organic molecules is the capability of templating complexly structured inorganic materials. The focus of this Minireview is on nanostructured silica with divergent morphologies and/or integrated chirality directed by organic templates of self‐assembled polyamine/polypeptides/block copolymers, chiral organogels, self‐organized chiral amphiphiles and chiral crystalline complexes, etc., by biomimetic silicification and conventional sol–gel reaction. Among them, biosilica (diatoms and sponges)‐inspired biomimetic silicifications are particularly highlighted.     

Emulsions with structured continuous phases

Recent research on the role of the continuous phase in emulsions is reviewed. Special attention is given to the structured continuous phases such as lyotropic and thermotropic liquid crystals and gel networks. The implications in the formation, stability and properties of emulsions are discussed. Some recent applications, particularly in templating for the preparation of new materials, are also introduced.     

Double direct templating of periodically nanostructured ZnS hollow microspheres

We introduce a "double direct templating" method for obtaining hollow microspheres with periodically nanostructured walls. Silica or polystyrene colloids are dispersed in a self-assembled hexagonal lyotropic liquid crystal containing precursors for ZnS. The semiconductor ZnS mineralizes on the surface of the colloid, expressing a pore morphology that is a copy of the structure of the liquid crystal. After etching of the sacrificial colloids, hollow capsules with templated and uniform mesoporous shells are obtained.     

Lyotropic liquid crystal engineering-ordered nanostructured small molecule amphiphile self-assembly materials by design

Future nanoscale soft matter design will be guided to a large extent by the teachings of amphiphile (lipid or surfactant) self-assembly. Ordered nanostructured lyotropic liquid crystalline mesophases may form in select mixtures of amphiphile and solvent. To reproducibly engineer the low energy amphiphile self-assembly of materials for the future, we must first learn the design principles. In this critical review we discuss the evolution of these design rules and in particular discuss recent key findings regarding (i) what drives amphiphile self-assembly, (ii) what governs the self-assembly structures that are formed, and (iii) how can amphiphile self-assembly materials be used to enhance product formulations, including drug delivery vehicles, medical imaging contrast agents, and integral membrane protein crystallisation media. We focus upon the generation of 'dilutable' lyotropic liquid crystal phases with two- and three-dimensional geometries from amphiphilic small molecules (225 references).