The first synergistic dual‐template self‐assembly approach is presented for bottom‐up construction of 2D mesoporous polypyrrole nanosheets based on different supramolecular assemblies, which feature ...a double‐layered architecture, controlled pore sizes, ultrathin thickness, and large surface area. The unique structure rends them with superior reversible discharge capability, rate performance, and stable cyclability when serving as the cathode materials for Na‐ion batteries.
Polymer self‐assembly commonly suffers from retarded equilibrium structure formation caused by the large diffusion barrier of long‐chain molecules. In particular, the defect annihilation kinetics of ...high‐χ block copolymers (BCPs) are generally sluggish because of a slow inter‐block chain diffusion process from strong inter‐block segregation. Therefore, long‐range order of high‐χ BCPs still hard to be obtained by conventional approaches. Here, we introduce near‐infrared laser photothermal treatment to effectively promote high‐χ BCP self‐assembly and demonstrating highly aligned nanoscale patterned structures on silicon substrates. Adequate molecular weight selection of high‐χ PS‐b‐P2VP system enables one‐time laser hot‐zone annealing, resulting in highly ordered nanodomains along laser writing direction. Facile sub‐sequential metal ion loading to P2VP cylinders enables the formation of highly aligned metal nanowires. Moreover, a commonly used silicon substrate without a photoabsorbing layer is employed as a photo‐thermal substrate, demonstrating that the laser writing process is compatible with conventional semiconductor processes.
Directed self‐assembly of a high‐χ block copolymer by laser writing, PS‐b‐P2VP, is demonstrated. Proper selection of molecular weight and thin film geometry can effectively suppress the segregation strength of the system, enabling the utilization of the hot‐zone annealing mechanism‐based laser writing process. A common silicon substrate is employed as a photothermal substrate, demonstrating that this laser writing process can be readily applied to conventional semiconductor processes.
A C3‐symmetric benzene‐1,3,5‐tricarboxamide substituted with ethyl cinnamate was found to self‐assemble into supramolecular gels with macroscopic chirality in a DMF/H2O mixture. The achiral compound ...simultaneously formed left‐ and right‐handed twists in an unequal number, thus resulting in the macroscopic chirality of the gels without any chiral additives. Furthermore, ester–amide exchange reactions with chiral amines enabled the control of both the handedness of the twists and the macroscopic chirality of the gels, depending on the structures of the chiral amines. These results provide new prospects for understanding and regulating symmetry breaking in assemblies of supramolecular gels formed from achiral molecular building blocks.
The self‐assembly of achiral and C3‐symmetric benzene‐1,3,5‐tricarboxamides (BTAC) in DMF/H2O mixtures without any chiral dopants led to supramolecular gels that showed macroscopic chirality. The unequal number of left‐ and right‐handed twists and thus the macroscopic chirality of the gels could be controlled through amide–ester exchange reactions.
Analytical methods that enable visualization of nanomaterials derived from solution self‐assembly processes in organic solvents are highly desirable. Herein, we demonstrate the use of stimulated ...emission depletion microscopy (STED) and single molecule localization microscopy (SMLM) to map living crystallization‐driven block copolymer (BCP) self‐assembly in organic media at the sub‐diffraction scale. Four different dyes were successfully used for single‐colour super‐resolution imaging of the BCP nanostructures allowing micelle length distributions to be determined in situ. Dual‐colour SMLM imaging was used to measure and compare the rate of addition of red fluorescent BCP to the termini of green fluorescent seed micelles to generate block comicelles. Although well‐established for aqueous systems, the results highlight the potential of super‐resolution microscopy techniques for the interrogation of self‐assembly processes in organic media.
Super‐resolution: Stimulated emission depletion microscopy (STED) and single‐molecule localization microscopy (SMLM) have been employed to map living crystallization‐driven block copolymer (BCP) self‐assembly in organic media and determine micelle length distributions in situ.
One plausible approach to endow aerogels with specific properties while preserving their other attributes is to fine‐tune the building blocks. However, the preparation of metallic aerogels with ...designated properties, for example catalytically beneficial morphologies and transition‐metal doping, still remains a challenge. Here, we report on the first aerogel electrocatalyst composed entirely of alloyed PdNi hollow nanospheres (HNSs) with controllable chemical composition and shell thickness. The combination of transition‐metal doping, hollow building blocks, and the three‐dimensional network structure make the PdNi HNS aerogels promising electrocatalysts for ethanol oxidation. The mass activity of the Pd83Ni17 HNS aerogel is 5.6‐fold higher than that of the commercial Pd/C catalyst. This work expands the exploitation of the electrocatalysis properties of aerogels through the morphology and composition control of its building blocks.
Function follows form: Aerogel electrocatalysts consisting of alloyed PdNi hollow nanospheres (HNS) were prepared. Their chemical composition and shell thickness can be controlled based on the ratio of the Ni/Pd precursors. The mass activity of the Pd83Ni17 HNS aerogel is 5.6 times higher than that of the commercial Pd/C catalyst.
•A fundamental description of the energy transfer steps comprising the TTA-UC process.•Current state of the art: Moving TTA-UC from the liquid domain to the solid state.•Design strategies and ...principles for future, efficient solid state TTA-UC systems.
Photon upconversion through sensitized Triplet–Triplet Annihilation (TTA-UC) has regained a lot of interest during the last decade mainly due to its potential for significantly increased solar energy harvesting. Other applications such as anti-Stokes fluorescence labels for bio-imaging and drug-targeting have also emerged. Considering practical large scale use of TTA-UC, solid state materials are required. The TTA-UC process depends on a sequence of energy transfer processes and it is a great challenge to maintain high efficiencies while solidifying these diffusion limited energy transfer steps. This review covers the basic, fundamental aspects of TTA-UC, but focuses on the current state of the art of the many attempts to develop solid state based TTA-UC systems. In particular, work aiming at overcoming the diffusion limit though supramolecular, macromolecular or self-assembly approaches are highlighted.
Self-Assembled Gelators for Organic Electronics Babu, Sukumaran Santhosh; Prasanthkumar, Seelam; Ajayaghosh, Ayyappanpillai
Angewandte Chemie (International ed.),
February 20, 2012, Letnik:
51, Številka:
8
Journal Article
Recenzirano
Nature excels at engineering materials by using the principles of chemical synthesis and molecular self‐assembly with the help of noncovalent forces. Learning from these phenomena, scientists have ...been able to create a variety of self‐assembled artificial materials of different size, shapes, and properties for wide ranging applications. An area of great interest in this regard is solvent‐assisted gel formation with functional organic molecules, thus leading to one‐dimensional fibers. Such fibers have improved electronic properties and are potential soft materials for organic electronic devices, particularly in bulk heterojunction solar cells. Described herein is how molecular self‐assembly, which was originally proposed as a simple laboratory curiosity, has helped the evolution of a variety of soft functional materials useful for advanced electronic devices such as organic field‐effect transistors and organic solar cells. Highlights on some of the recent developments are discussed.
All gelled together: Solvent‐assisted gelation of functional organic molecules leading to one‐dimensional fibers is an area of great interest. Recent developments in molecular self‐assembly‐assisted gelation of π systems into soft functional materials and their potential application in organic electronic devices, such as organic field‐effect transistors and organic solar cells, are reviewed (see picture).
Supramolecular self‐assembly shows significant potential to construct responsive materials. By tailoring the structural parameters of organic building blocks, nanosystems can be fabricated, whose ...performance in catalysis, energy storage and conversion, and biomedicine has been explored. Since small organic building blocks are structurally simple, easily modified, and reproducible, they are frequently employed in supramolecular self‐assembly and materials science. The dynamic and adaptive nature of self‐assembled nanoarchitectures affords an enhanced sensitivity to the changes in environmental conditions, favoring their applications in controllable drug release and bioimaging. Here, recent significant research advancements of small‐organic‐molecule self‐assembled nanoarchitectures toward biomedical applications are highlighted. Functionalized assemblies, mainly including vesicles, nanoparticles, and micelles are categorized according to their topological morphologies and functions. These nanoarchitectures with different topologies possess distinguishing advantages in biological applications, well incarnating the structure–property relationship. By presenting some important discoveries, three domains of these nanoarchitectures in biomedical research are covered, including biosensors, bioimaging, and controlled release/therapy. The strategies regarding how to design and characterize organic assemblies to exhibit biomedical applications are also discussed. Up‐to‐date research developments in the field are provided and research challenges to be overcome in future studies are revealed.
Nanoparticles self‐assembled from small organic building blocks show a promising application potential for biomedical applications such as cancer theranostics. The dynamic property of rationally designed building blocks enables self‐assembled nanoparticles with high performance in biosensors, bioimaging, and drug delivery.
Simple and powerful: Two germanium/carbon nanostructures were synthesized through a facile self‐assembly method. Controlling the size of the precursor germanium nanoparticles produces cluster and ...non‐clustered nanostructures. The cluster‐Ge/C sample showed better capacity retention and an exceptionally high rate performance (see picture; Q=charge capacity and V=voltage).
Plasmonic chiroptical effects have attracted significant attention for their widespread potential applications in negative‐refractive‐index materials, advanced light‐polarization filters, and ...ultrasensitive sensing devices, etc. As compared to top‐down fabrication methods, the bottom‐up self‐assembly strategy provides nanoscale resolution, parallel production, and isotropic optical response, and therefore plays an indispensable role in the fabrication of chiral plasmonic nanostructures. The optical properties of these chiral structures can be predicted based on the near‐field coupling of localized surface plasmons in structural components, which offers a route to tune or enhance optical activity by selecting building blocks and designing structural configurations. To date, three main types of chiral plasmonic nanostructures, i.e., chiral “plasmonic molecules”, chiral superstructures, and chiral‐molecule–metal hybrid complexes, are usually assembled, in which metal nanoparticles with various sizes, shapes, and compositions, and/or chiral molecules are employed as building blocks. Here, recent achievements in the self‐assembly of chiral plasmonic nanostructures are highlighted and perspectives on the future directions of chiral plasmonics integrated with bottom‐up self‐assembly are presented, showing three typical examples, including chiral plasmonic switches, chiral nanoparticles, and chiral metamaterials.
A large variety of chiral plasmonic nanostructures can be achieved with bottom‐up self‐assembly methods, including DNA‐, peptide‐, and cellulose‐nanocrystal‐directed chiral arrangement of nanoparticles. Self‐assembled chiral plasmonic nanostructures exhibit novel optical activity in the visible wavelength region, and pave the way for the progress of chiral plasmonics.
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