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Photonic Titanium dioxide film obtained from hard template with chiral nematic structure for environmental application
摘要： In the present work, mesoporous TiO2 with a photonic structure was elaborated using cellulose nanocrystals (CNCs) as a biotemplate by two-step hard template methods. This strategy enables to replicate the chiral nematic (CN) structure of the photonic films (biotemplate) in TiO2 films. A series of iridescent CNCs films with different weight ratios of silica/CNCs composite photonic films were prepared via evaporation induced self-assembly (EISA) method. The films showed iridescent color and tuneable Bragg reflection wavelengths by solely changing the ratio between the silica and the CNCs biotemplate. Polarized optical microscopy (POM) performed on hydride SiO2/CNCs films showed a birefringence and typical fingerprint of chiral nematic structure. This birefringence was also observed for TiO2 films obtained using SiO2 films as a hard template, which suggested the transfer of the chiral nematic structure in TiO2 materials. Afterwards, their optical, morphological and electronic properties were studied by scanning electron microscope (SEM), POM, energy-dispersive X-ray spectroscope (EDX) and time resolved microwave conductivity (TRMC). The photocatalytic activities were evaluated by following the phenol degradation using high performance liquid chromatography (HPLC). The results showed that the structuration of the TiO2 film using a chiral nematic SiO2 film as hard template enhances the photocatalytic performance compared to non-structured mesoporous TiO2.
关键词： hard template,cellulose nanocrystals,iridescent film,evaporation induced self-assembly,light harvesting,phenol degradation,chiral nematic structure
更新于2025-09-23 15:22:29
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AIE-active Metal-organic Coordination Complexes Based on Tetraphenylethylene Unit and Their Applications
摘要： Tetraphenylethylene (TPE) and its derivatives, as the widely used aggregation-induced emission (AIE) fluorophores, have attracted rapidly growing interest in the fields of material science and biological technology due to their unique light-emitting mechanism—they are nearly non-emissive in dilute solution but emit brilliant fluorescence in the aggregate state because of the restriction of intramolecular motion. Coordination-driven self-assembly, which provides a highly effective method to put the individual chromophores together, is consistent with the AIE mechanism of TPE. During the past few years, some AIE-active metal-organic coordination complexes have been successfully constructed via coordination-driven self-assembly, and their AIE properties and applications have been investigated. In this review, we survey the recent progress on TPE-based metal-organic coordination complexes and their applications in fluorescence sensors, cell imaging, and light-emitting materials. We will introduce them from three different types of structures: metallacycles, metallacages, and metal-organic frameworks (MOFs).
关键词： Tetraphenylethylene,Self-assembly,Aggregation-induced emission,Sensor,Metal-organic coordination complexes
更新于2025-09-23 15:22:29
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Ordered Particle Arrays via a Langmuir Transfer Process: Access to Any Two-Dimensional Bravais Lattice
摘要： We demonstrate how to directly transform a close-packed hexagonal colloidal monolayer into non-close packed particle arrays of any two-dimensional symmetry at the air/water interface. This major advancement in the field of nanoparticle self-assembly is based on a simple one-dimensional stretching step in combination with the particle array orientation. Our method goes far beyond existing strategies and allows access to all possible 2D Bravais lattices. A key element of our work is the possibility to macroscopically stretch a particle array in a truly one-dimensional manner, which has not been possible up to now. We achieve this by stretching the nanoparticle array at an air/water interface during the transfer process. The degree of stretching is simply controlled by the wettability of the transfer substrate. To retain the symmetry of the transferred structure, the capillary forces upon drying have to be circumvented. We demonstrate two concepts based on thermal fixation for this. It allows for the first time to fabricate non-close packed, non-hexagonal colloidal monolayers on a macroscopic length scale.
关键词： guided assembly,interfacial self-assembly,colloidal self-assembly,non-close-packed monolayers
更新于2025-09-23 15:21:21
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Self-Assembly of Amphiphilic Schiff Base and Selectively Turn on Circularly Polarized Luminescence by Al3+
摘要： We designed glutamide-derived amphiphilic Schiff bases containing three different aldehyde moieties for the fabrication of circularly polarized luminescence (CPL) emitting materials. Upon self-assembly in acetonitrile, Schiff bases featuring 4-(dimethylamino)-2-hydroxylbenzaldehyde and 1-hydroxy-2-naphthaldehyde groups form supramolecular gels with twist and fiber structures, respectively, while Schiff bases featuring 2-hydroxy-1-naphthaldehyde groups forms precipitation with flakes structures. Although emission and circular dichroism (CD) signals can be detected from the supramolecular gels formed by amphiphilic Schiff bases, none of them exhibits circularly polarized luminescence (CPL). While Mg2+, Zn2+ and Al3+ can both significantly enhance the fluorescence of the Schiff bases, interestingly, only Al3+ ion is able to turn on the CPL emission. This study on the one hand provides a simple method to the fabrication of CPL emitting supramolecular materials, and on the other hand offers a novel way to the sensing of aluminum ion with supramolecular materials.
关键词： Self-assembly,Schiff bases,Circularly polarized luminescence,Al3+,Supramolecular gels
更新于2025-09-23 15:21:21
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Control on Dimensions and Supramolecular Chirality of Self-Assemblies through Light and Metal Ions
摘要： Precise control over helical chirality and dimensions of molecular self-assemblies, a remaining challenge for both chemists and materials scientists, is the key to manipulate the property and performance of supramolecular materials. Herein, we report that a cholesterol-azopyridine conjugate could self-assemble into organogels with photo-controllable dimensional transition from 2D microbelts to 1D nanotubes and finally to 0D nanoparticles. The E/Z-Photoisomerization of the 4-azopyridine unit is the major driving force for the dimensional transformation. Furthermore, the self-assembled structures were observed to exhibit metal ion-mediated helicity inversion through the metal coordination. These observations were collectively confirmed by several techniques including scanning electron microscopy, atomic force microscope, circular dichroism, and X-ray crystallography. The rational design of building blocks for the construction of dimension and chirality controllable self-assembly systems may lead to versatile applications in smart display, advanced optoelectronic device, and supramolecular asymmetric catalysis.
关键词： photoisomerization,dimensional transition,supramolecular chirality,metal coordination,self-assembly
更新于2025-09-23 15:21:21
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A self-assembly/disassembly two-photo ratiometric fluorogenic probe for bacteria imaging
摘要： A fluorogenic probe for bacteria imaging was reported. The binding with anionic bacterial surfaces disassembled the self-assembly probe to turn-on the fluorescence and shift pyrene monomer/excimer ratiometric signals.
关键词： Self-assembly,Pyrene,Bacteria,Fluorogenic probe,Imidazolium
更新于2025-09-23 15:21:21
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Preparing Semiconducting Nanoribbons with Tunable Length and Width via Crystallization-Driven Self-Assembly of a Simple Conjugated Homopolymer
摘要： Precise control of width and length of one-dimensional (1D) semiconducting nanostructures has attracted much attention owing to its potential for optoelectronic applications. However, regulating both their length and width using conjugated polymers or even block copolymers is a huge challenge. To solve this problem, we synthesized a unique conjugated polyacetylene homopolymer by living cyclopolymerization, which spontaneously formed 1D nanoribbons via in situ nanoparticlization. Interestingly, their widths could be controlled from 8 to 41 nm, which were directly proportional to their degree of polymerization. Furthermore, a self-seeding technique via crystallization-driven self-assembly (CDSA) was used to control the length of the nanoribbons up to 5.2 μm with narrow distributions less than 1.1. Interestingly, adding a block copolymer unimer to these nanoribbons produced triblock comicelles by the living CDSA mechanism. Finally, these nanoribbons were visualized directly by super-resolution optical fluorescence microscopy. Now, one can modulate both length and width of 1D nanoribbons simultaneously.
关键词： semiconducting nanostructures,crystallization-driven self-assembly,nanoribbons,optoelectronic applications,conjugated polymers
更新于2025-09-23 15:21:21
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Self-Assembly of a Carboxyl-Functionalized BODIPY Dye via Hydrogen Bonding
摘要： We report the synthesis, characterization, and self-assembly behavior of a 4,4-Difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) dye functionalized at the meso-position with a butyric acid group. Various spectroscopic investigations (UV-Vis, emission, and Fourier-transform infrared spectroscopy (FTIR) studies) supported by X-ray analysis revealed the formation of self-assembled structures in the solid state with translationally stacked BODIPY units driven by hydrogen bonding between the carboxyl groups.
关键词： hydrogen bonding,Self-Assembly,weak non-covalent interactions,BODIPY dyes
更新于2025-09-23 15:21:21
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Supramolecular Photothermal Nanomaterials as an Emerging Paradigm toward Precision Cancer Therapy
摘要： The concept of the “supramolecular photothermal effects” refers to the collection property and photothermal conversion efficiency resulting from the supramolecular assembly of molecular photothermal sensitizers. This review considers organic supramolecular photothermal materials assembled at the nanoscale via various molecular self-assembly strategies and associated with the organization of multiple noncovalent interactions. In these materials, the individual photosensitizer molecules are typically aggregated through self-assembly in a certain form that exhibits enhanced biostability, increased photothermal conversion efficiency with photoluminescence quenching, and improved photothermal therapeutic effects in comparison with those of the monomeric photosensitizer molecules. These supramolecular photothermal effects are controlled or influenced by intermolecular noncovalent interactions, especially the hydrophobic effects, which are distinct from the mechanisms of conventional sensitizer molecules and polymers and inorganic photothermal agents. A focus lies on how self-assembly strategies give rise to supramolecular photothermal effects, including polymer and protein fabrication, small molecule self-assembly, and the construction of donor–acceptor binary systems. Emphases are placed on the rational design of supramolecular photothermal nanomaterials, drug delivery, and in vivo photothermal therapeutic effects. Finally, the key challenges and promising prospects of these supramolecular photothermal nanomaterials in terms of both technical advances and clinical translation are discussed.
关键词： photothermal therapy,nanomaterials,cancer therapy,supramolecular photothermal effects,self-assembly
更新于2025-09-23 15:21:21
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Liquid-Cell Scanning Transmission Electron Microscopy and Fluorescence Correlation Spectroscopy of DNA-Directed Gold Nanoparticle Assemblies
摘要： In the use of solution-based 3D nanoarchitectures for optics, drug delivery, and cancer treatment, the precise nanoparticle architecture morphologies, architecture sizes, interparticle distances, and the assembly stability are all critical to their functionality. 3D nanoparticle architectures in solution are difficult to characterize, as few techniques can provide individualized information on interparticle spacing (defined by linkage molecule), nanoparticle assembly size, morphology, and identification of false aggregation. Bulk characterization techniques, including small angle x-ray scattering, can provide architecture sizes, though they are unable to precisely measure differences within interparticle spacings for individual architectures and can falsely measure assemblies caused by non-linkage grouped nanoparticles. Two solution-based characterization techniques were used to determine which assembly type and linkage length would produce the fastest assembly rate for large DNA-directed gold nanoparticle assemblies. In-situ liquid-cell scanning transmission electron microscopy (STEM), measured interparticle spacings between DNA-functionalized nanoparticles, and fluorescence correlation spectroscopy provided the bulk volume fraction of large and small assemblies for nanoparticle architectures that were assembled using two different types: (1) the hybrid assemblies join two complementary single-stranded DNA linkages, and (2) the bridged assemblies are comprised of single-stranded DNA (bridging component) that is double the length of two different complementary single-stranded DNA-functionalized gold nanoparticles (Fig. 1). Assembly times were tested at 24-hour intervals over 3 days. Statistics derived from the in-situ liquid-cell STEM images provided data for interparticle distance measurements, which identified the fraction of nanoparticles within the images acquired that were at the expected double-stranded DNA-binding distance of the linkages (varied in three distances for each of the two different architectures). In general, longer linkage lengths assembled in the shortest amount of time. The bridged assemblies formed fewer large architectures at 24-hours but ultimately assembled a greater fraction of nanoparticles, which was due to the longer functionalized DNA lengths for individual nanoparticles. Fluorescence correlation spectroscopy provided a bulk average of the gold nanoparticle assembly sizes over time, which supported the conclusions drawn from the in-situ liquid-cell STEM data. The microscopy provided sub-2 nanometer precision in the interparticle distances between gold nanoparticles in a solution environment. This coupled microscopy and spectroscopy characterization approach can provide more detailed information than bulk characterization methods.
关键词： gold,nanoparticle,DNA,FCS,assembly,liquid-cell TEM
更新于2025-09-23 15:21:21