Perylenediimide-surfactant complexes: thermotropic liquid-crystalline materials via ionic self-assembly

In this communication we present the facile preparation and characterisation of thermotropic liquid-crystalline materials from the ionic self-assembly of a charged perylenediimide derivative and oppositely charged surfactants.     

Hierarchical self-assembly of surfactant-encapsulated and organically grafted polyoxometalate complexes

A series of surfactant-encapsulated and organically grafted polyoxometalates (SEOPs) were prepared through a co-precipitation procedure. Through a rational selection of the molecular components in the structure of the complex, SEOP complexes self-assemble into ordered aggregates with two different hierarchical self-assembled structures in an organic solvent mixture of dichloromethane and methanol in different volume ratios. FTIR, (1)H NMR, and X-ray photoelectron spectroscopy were used to characterize the self-assembly process and the involved driving forces. In a weakly polar solvent, SEOPs aggregated into fibers with a lamellar structure. When the solvent polarity was increased, SEOPs formed ribbonlike aggregates with a tetragonal structure. The change of the hierarchical self-assembled structure was deduced in regard to the arrangement of alkyl chains, electrostatic interactions, and hydrogen bonding between the pyridyl groups and terminal oxygen atoms of the polyoxometalates. The ribbonlike aggregates exhibit birefringence due to the ordered arrangement of SEOPs in the microstructure.     

非共价键自组装有机功能材料

分子自组装对于某些化学反应过程、生物化学过程及生命活动的模拟等方面具有重要的意义。本文对非共价键组装方式自组装的有机功能材料的分类，结构、性质、自组装机理以及研究进展进行了综述。     

Metallopolymer-peptide hybrid materials: synthesis and self-assembly of functional, polyferrocenylsilane-tetrapeptide conjugates

Conjugates of poly(ferrocenyldimethylsilane) (PFDMS) with Ac-(GA)(2)-OH, Ac-A(4)-OH, Ac-G(4)-OH and Ac-V(4)-OH have been prepared by reaction of the tetrapeptide units with the amino-terminated metallopolymer. The number average degree of polymerisation (DP(n)) of the PFDMS was approximately 20 and comparable materials with shorter (DP(n) ≈ 10) and/or amorphous chains have been prepared by the same procedure. Poly(ferrocenylethylmethylsilane) (PFEMS) was employed for the latter purpose. All conjugates were characterised by GPC, MALDI-TOF?MS, NMR and IR spectroscopy. With the exception of Ac-V(4)-PFDMS(20), all materials exhibited some anti-parallel β-sheet structure in the solid state. The self-assembly of the conjugates was studied in toluene by DLS. The vast majority of the materials, irrespective of peptide sequence or chain crystallinity, afforded fibres consisting of a peptidic core surrounded by a PFS corona. These fibres were found in the form of cross-linked networks by TEM and AFM. The accessibility of the chemically reducing PFS corona has been demonstrated by the localised formation of silver nanoparticles on the surface of the fibres.     

Fabrication of functional nano-objects via self-assembly of nanostructured hybrid materials

A simple route to fabricate functional nano-objects via self-assembly of block copolymer-based hybrid materials is described. In water–toluene mixtures, spheres, rod-like morphologies, and ring-like morphologies as well as vesicles of metal loaded block copolymers micelles are fabricated. The concept is generic to realize different functionalities by incorporating various inorganic components (Au, Ag, Pt, Co…) into the block copolymer matrix. A mechanism describing the formation of micellar aggregates with different morphologies is presented based on a simple force balance approach. Moreover, the composition of the solvent mixture is modified to gain control over the morphology of micellar aggregates. It was found that swelling of the micelle core with a selective cosolvent is the driving force to induce morphology transitions from spherical to rod- and ring-like structures as well as vesicles. These nano-objects can be further used as building blocks to construct well-defined structures via self-assembly in spin coated thin films. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1642–1650, 2010     

Hierarchical porphyrin self-assembly in aqueous solution

In aqueous solution meso-tetrakis(4-phosphonatophenyl)porphyrin shows self-aggregation processes controlled by the "sergeant-soldier rule". After partial protonation of the external phosphonic groups, it is possible (i) to further protonate the inner nitrogen atoms of the molecules or (ii) to allow, over time, the system to aggregate. Therefore, the two procedure lead to a different system evolution, producing species with different chemico-physical properties.     

Hierarchical self-assembly of noncovalent amphiphiles

Amphiphiles defined by noncovalent inclusion complexes between an alkylated beta-cyclodextrin and PEG-conjugated guests assemble into higher-ordered structures whose thermodynamic stability reflects that of the defining intermolecular interactions.     

Hierarchical self-assembly of columnar aggregates

Biology often uses hierarchical self-assembly to produce complex functional structures from smaller components. At each level of this stepwise process, non-covalent interactions bring together the subunits of a lower level of complexity, using the information encoded in their structures. Applying this approach to synthetic systems represents a formidable challenge, because it requires a high degree of command of non-covalent interactions. In this tutorial review, recent developments in the hierarchical self-assembly of discrete columnar aggregates are discussed.     

Hierarchical self-assembly into chiral nanostructures

One basic principle regulating self-assembly is associated with the asymmetry of constituent building blocks or packing models. Using asymmetry to manipulate molecular-level devices and hierarchical functional materials is a promising topic in materials sciences and supramolecular chemistry. Here, exemplified by recent major achievements in chiral hierarchical self-assembly, we show how chirality may be utilized in the design, construction and evolution of highly ordered and complex chiral nanostructures. We focus on how unique functions can be developed by the exploitation of chiral nanostructures instead of single basic units. Our perspective on the future prospects of chiral nanostructures via the hierarchical self-assembly strategy is also discussed.

This review shows how chirality may be used for the design, construction and evolution of higher ordered and complex chiral nanostructures through hierarchical self-assembly.     

Hierarchical self-assembly: when sugar meets amino acid

正Life is an extremely delicate self-assembly system,where a rich array of small molecules,macromolecules and other entities associate and organize in an intrinsically diverse and precise manner.During the past few decades,scientists have     

Hierarchical assembly of micro-/nano-building blocks: bio-inspired rigid structural functional materials

The huge diversity of hierarchical micro-/nano-rigid structures existing in biological systems is increasingly becoming a source of inspiration of materials scientists and engineers to create next-generation advanced functional materials. In the past decades, these multiscale hierarchical structures have been intensively investigated to show their contributions to high performance in mechanical properties. Recently, accompanied with the development of nanotechnology, some biologically hierarchical rigid structures have been duplicated and mimicked in artificial materials through hierarchical organization of micro-/nano-building blocks. In this critical review, we will present biological rigid structural models, functional micro-/nano-building blocks, and hierarchical assembly techniques for the manufacture of bio-inspired rigid structural functional materials (177 references).     

Hierarchical self-assembly of all-organic photovoltaic devices

Photovoltaic devices built by a hierarchical self-assembly process using hydrogen-bonding terminated self-assembled monolayers (SAMs) on gold and the combination of a hydrogen-bonding barbituric acid appended fullerene and a complementary melamine terminated π-conjugated thiophene-based oligomer are presented. The incorporation of these electron donor (oligomer) and electron acceptor (methanofullerene) assemblies into simple photovoltaic (PV) devices as thin films leads to a 2.5 fold-enhancement in photocurrent compared to analogous systems comprising non-hydrogen-bonding C₆₀-oligomer systems, which is ascribed to higher molecular-level ordering. The modification of the gold electrode surface with self-assembled monolayers bearing hydrogen-bonding molecular recognition endgroups was seen to further enhance the PV response of the corresponding functional supramolecular device. This superposition of two types of self-assembly facilitates the generation of binary supramolecular fullerene-containing architectures. Importantly, all functional materials are accessible in a direct fashion.     

Synthesis and self-assembly of amphiphilic polymeric microparticles

We report the synthesis and self-assembly of amphiphilic, nonspherical, polymeric microparticles. Wedge-shaped particles bearing segregated hydrophilic and hydrophobic sections were synthesized in a microfludic channel by polymerizing across laminar coflowing streams of hydrophilic and hydrophobic polymers using continuous flow lithography (CFL). Particle monodispersity was characterized by measuring both the size of the particles formed and the extent of amphiphilicity. The coefficient of variation (COV) was found to be less than 2.5% in all measured dimensions. Particle structure was further characterized by measuring the curvature of the interface between the sections and the extent of cross-linking using FTIR spectroscopy. The amphiphilic particles were allowed to self-assemble in water or at water-oil interfaces. In water, the geometry of the particles enabled the formation of micelle-like structures, while in emulsions, the particles migrated to the oil-water interface and oriented themselves to minimize their surface energy.     

Hierarchical luminescence patterning based on multiscaled self-assembly

This communication describes a procedure for fabrication of hierarchical luminescence patterns based on the template-assisted assembly of CdSe nanocrystals on a self-assembled structure with green-emitting microstripes, as well as the photoinduced fluorescence enhancement of CdSe nanocrystals and photobleaching of dyes. The technique is low-cost and high-throughput and can be extended to many material combinations.     

Calixarene-encapsulated nanoparticles: self-assembly into functional nanomaterials

Calixarenes are excellent surfactants for enhancing the dispersion and self-assembly of metal nanoparticles into well-defined structures, particularly those with unit length scales in the 10-100 nm size range. Particles within these ensembles are strongly coupled, giving rise to unique collective optical or magnetic properties. The self-assembled nanostructures described in this feature article include 2D arrays of colloidal Au nanoparticles with size-dependent plasmonic responses, and sub-100 nm Co nanoparticle rings with chiral magnetic states. These nanoparticle assemblies may be further developed for applications in chemical sensing based on surface-enhanced Raman scattering (SERS) and as binary elements for nonvolatile memory, respectively.     

Metal complexes with polymeric ligands: modular synthesis of multifunctional materials for applications in biomedicine and nanotechnology

Polymeric metal complexes exhibiting useful properties were prepared by chelating macroligands to labile and inert metal ions. The specific structures elucidated through this method, as well as potential applications for these complexes are described. By carefully selecting the appropriate metal ion and polymer, these materials can be tuned for a host of applications in fields ranging from biomedicine to nanotechnology.     

PolyChemPrint: A hardware and software framework for benchtop additive manufacturing of functional polymeric materials

Additive manufacturing (AM, 3D Printing) of hierarchical polymer structures for a targeted function represents a grand challenge in the field of polymer science and engineering. Because advanced functional materials often do not possess suitable mechanical and rheological properties for conventional fused deposition modeling, a key challenge that researchers face is in integrating custom deposition tool heads that enable printing of non-filamentary materials while preserving synchrony with the motion axes. In this article, we demonstrate a highly versatile hardware and software platform for melt and solution-phase benchtop AM and highlight patterning and post-deposition processing of a series of non-filament forming functional polymers, including PS-b-PLA bottlebrush block copolymers, semiconducting polymer DPP2T-TT, conducting polymer PEDOT:PSS [poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)], and an SiO₂-PE nanoporous polymer matrix composite. We present a free and open-source Python module, PolyChemPrint, which serves as a research-optimized AM control software. The cross-platform (Windows/Linux) software is designed to be extremely flexible in terms the hardware that can be connected and a detailed user manual and developer guide are provided for use by researchers without extensive computer programming experience. Finally, we provide extensive details of the hardware used for operation of low- and high-pressure pneumatic extruders and a laser module as rapidly interchangeable tool heads.     

Hierarchical self-assembly of aminopyrazole peptides into nanorosettes in water

Self-association of aminopyrazole peptide hybrid 1 leads to stacked nanorosettes. This remarkable, well-ordered structure obeys the laws of nucleic acid self-assembly. In a strictly hierarchical process, formation of aminopyrazole "base" triplets via a hydrogen bond network is accompanied by pi-stacking with a second rosette and final dimerization of two double rosettes to a four-layer superstructure, stabilized by a six-fold half-crown alkylammonium lock. The final complex is soluble in organic as well as in aqueous solution. It was characterized in the solid state by X-ray crystallography, in water by NMR spectroscopy, and in silico by quantum chemical shift calculation. All these methods provide strong evidence for the same hexameric complex geometry. Its structural features bear striking similarity to nucleic acid architectures and their peptidic counterparts, especially alanyl-PNA. The whole self-assembly process is highly solvent- and temperature-dependent and occurs with a high degree of cooperativity--no intermediates are observed. Formation and dissociation of the nanorosette, however, are kinetically slow. The limitation to a hexameric aggregate can be explained by six sterically demanding valine residues, whose replacement by alanines may result in formation of infinite fibers.     

Reversible shape-shifting in polymeric materials

In recent years, significant progress has been made in polymeric materials, which alter shape upon external stimuli, suggesting potential applications in robotics, biomedical engineering, and optical devices. These stimuli-responsive materials may be categorized into two classes: (i) shape-changing materials in which a specific type of shape-shifting is encoded in the original material structure and (ii) shape-memory materials, which do not possess any predetermined shape-shifting as prepared, yet allow programming of complex shape transformations on demand. While shape alterations in shape-changing materials are intrinsically reversible, shape memory is usually a one-way transformation from a metastable (programmed) to an equilibrium (original) state. Recently, different principles for both one-way reversible and two-way reversible shape memory have been developed. These offer a powerful combination of reversibility and programmability, which significantly expands the range of potential applications. The goal of this review is to highlight recent developments in reversible shape-shifting by introducing novel mechanisms, materials, and applications. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1365–1380     

Exceptional affinity of nanostructured organic-inorganic hybrid materials towards dioxygen: confinement effect of copper complexes

We report the exceptional reactivity towards dioxygen of a nanostructured organic-inorganic hybrid material due to the confinement of copper cyclam within a silica matrix. The key step is the metalation reaction of the ligand, which can occur before or after xerogel formation through the sol-gel process. The incorporation of a Cu(II) center into the material after xerogel formation leads to a bridged Cu(I)/Cu(II) mixed-valence dinuclear species. This complex exhibits a very high affinity towards dioxygen, attributable to auto-organization of the active species in the solid. The remarkable properties of these copper complexes in the silica matrix demonstrate a high cooperative effect for O(2) adsorption; this is induced by close confinement of the two copper ions leading to end-on mu-eta(1):eta(1)-peroxodicopper(II) complexes. The anisotropic packing of the tetraazamacrocycle in a lamellar structure induces an exceptional reactivity of these copper complexes. We show for the first time that the organic-inorganic environment of copper complexes in a silica matrix fully model the protecting role of protein in metalloenzymes. For the first time an oxygenated dicopper(II) complex can be isolated in a stable form at room temperature, and the reduced Cu(2) (I,I) species can be regenerated after several adsorption-desorption cycles. These data also demonstrate that the coordination scheme and reactivity of the copper cyclams within the solid are quite different from that observed in solution.