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Helical nanostructures fabricated via the self‐assembly of artificial motifs have been a captivating subject because of their structural aesthetics and multiple functionalities. Herein, we report the facile construction of a self‐assembled nanohelix (NH) by leveraging an achiral aggregation‐induced emission (AIE) luminogen (G) and pillar[5]arene (H), driven by host–guest interactions and metal coordination. Inspired by the “sergeants and soldiers” effect and “majority rule” principle, the host–guest complexation between G and H is employed to fixate the twisted conformation of G for the generation of “contortion sites”, which further induced the emergence of helicity as the 1D assemblies are formed via Ag(I) coordination and hexagonally packed into nano‐sized fibers. The strategy has proved feasible in both homogeneous and heterogeneous syntheses. Along with the formation of NH, boosted luminescence and enhanced productivity of reactive oxygen species (ROS) are afforded because of the efficient restriction on G, indicating the concurrent regulation of NH′s morphology and photophysical properties by supramolecular assembly. In addition, NH also exhibits the capacity for bacteria imaging and photodynamic antibacterial activities against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). [ABSTRACT FROM AUTHOR]

Dynamic chemistry utilizing both covalent and noncovalent bonds provides valid protocols in manipulating properties of self‐assemblies and functions. Here we employ dynamic chemistry to realize multiple‐route control over supramolecular chirality up to five states. N‐protected fluorinated phenylalanine in the carboxylate state self‐assembled into achiral nanoparticles ascribed to the amphiphilicity. Protonation promoted one‐dimensional growth into helices with shrunk hydrophilicity, which in the presence of disulfide pyridine undergo chirality inversion promoted by the hydrogen bonding‐directed coassembly. Further interacting with the water‐soluble reductant cleavages the disulfide bond to initiate the rearrangement of coassemblies with a chirality inversion as well. Finally, by tuning the pH environments, aromatic nucleophilic substitution reaction between reduced products and perfluorinated phenylalanine occurs, giving distinct chiral nanoarchitectures with emerged luminescence and circularly polarized luminescence. We thus realized a particular five‐state control by combining dynamic chemistry at one chiral compound, which greatly enriches the toolbox in fabricating responsive chiroptical materials. [ABSTRACT FROM AUTHOR]

Many studies on the basis of cholesteric liquid crystal (CLC) have focused on dynamic optical changes utilizing photochemical reactions raising helical pitch variations. However, the conventional dyes doped in CLC system often show reversible isomerization such as trans‐cis, E‐Z, and open‐close forms that hampers the fixation of desired color cues. Here, a cyanostilbene‐based reactive mesogen (CSRM) for phototunable and subsequently polymerizable smart CLC paints is newly designed and synthesized. The structural color of the CLC paint can be precisely manipulated in remote controllable manner by inducing a photochemical reaction of CSRM. Due to the irreversible isomerization behaviors of CSRM, the constructed periodic structures with different helical pitches are intactly fixed via in situ photopolymerization under 460 nm light. In addition, the combination of helical nanostructures and cyanostilbene luminophore produces a circularly polarized light emission. The dissymmetry factor of circularly polarized luminescence is dependent on the photoregulated helical nanostructures in CLC films. The decoupled system of triple photofunctionality in a single component of chirophotonic crystalline material is applied to develop advanced optical information storages. [ABSTRACT FROM AUTHOR]

Examples of anisotropic movement paired with helical geometry abound in the animal and plant kingdoms are used for a variety of reasons, such as diverse social signaling directed at conspecifics or camouflage to avoid predation. Inspired by these natural phenomena, a smart sensor is developed with a chiroptical 3D actuator that can fold, bend, and twist in response to external stimuli, reflecting light of specific wavelengths, and possessing circular polarization properties. Chirophotonic crystal actuators are constructed with an asymmetric Janus structure and are fabricated by self‐assembly, screen printing, and in situ photopolymerization. The optically active layer consists of cholesteric liquid crystal polymer, and the mechanically active layer is composed of a polymeric gel thin film. The programmed in‐planar and out‐of‐planar asymmetric Janus structures control the directionality of various shapes morphing from 2D to 3D. Finite element simulations allow to predict the shape changes associated with these chirophotonic crystal actuators: flower blooming, tendril climbing, eagle hunting, ant lifting, and inchworm moving motions. By utilizing the chirophotonic crystal actuator, a reusable and portable methanol‐laced water identifier is developed. [ABSTRACT FROM AUTHOR]

Determining the structural origins of amyloid fibrillation is essential for understanding both the pathology of amyloidosis and the rational design of inhibitors to prevent or reverse amyloid formation. In this work, the decisive roles of peptide structures on amyloid self-assembly and morphological diversity were investigated by the design of eight amyloidogenic peptides derived from islet amyloid polypeptide. Among the segments, two distinct morphologies were highlighted in the form of twisted and planar (untwisted) ribbons with varied diameters, thicknesses, and lengths. In particular, transformation of amyloid fibrils from twisted ribbons into untwisted structures was triggered by substitution of the C-terminal serine with threonine, where the side chain methyl group was responsible for the distinct morphological change. This effect was confirmed following serine substitution with alanine and valine and was ascribed to the restriction of intersheet torsional strain through the increased hydrophobic interactions and hydrogen bonding. We also studied the variation of fibril morphology (i.e., association and helicity) and peptide aggregation propensity by increasing the hydrophobicity of the peptide side group, capping the N-terminus, and extending sequence length. We anticipate that our insights into sequence-dependent fibrillation and morphological diversity will shed light on the structural interpretation of amyloidogenesis and development of structure-specific imaging agents and aggregation inhibitors.

ABC triblock copolymers with frustrated interactions of χACN ≪ χABN ~ χBCN confined in nanopores with A‐block‐attracting surfaces can self‐assemble into helical morphologies, where the B blocks form helical domains wrapping around C‐core cylinders within the A shell. It has been suggested that the number of helical strands (m) increases as the volume fraction of C block (fC) decreases, while the increasing m is restricted because C blocks forming domains cannot maintain a cylindrical shape as fC gradually decreases, and the B block domains transform from helical structures to toroidal domains. To prevent the restriction of increasing m, in the current study we added C homopolymers into nanopores. For a given triblock copolymer with (χABN, χBCN, χACN) = (80, 80, 20) and (fA, fB, fC) = (0.7, 0.1, 0.2), varying the concentration (ϕH) and the chain length (γ) of the C homopolymers, as well as the diameter (D) of the nanopores, we constructed different two‐dimensional phase diagrams with respect to two of these control parameters using self‐consistent field theory. A number of helical structures with strands ranging from 1 to 6 are predicted. Our calculations indicate that m increases with increasing γ and D and decreasing ϕH. The theoretical results demonstrate that blending of homopolymer with one given triblock terpolymer could provide an efficient route to fabricate different complex helical nanostructures. © 2021 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

Designing broadband enhanced chirality is of strong interest to the emerging fields of chiral chemistry and sensing, or to control the spin orbital momentum of photons in recently introduced nanophotonic chiral quantum and classical optical applications. However, chiral light‐matter interactions have an extremely weak nature, are difficult to control and enhance, and cannot be made tunable or broadband. In addition, planar ultrathin nanophotonic structures to achieve strong, broadband, and tunable chirality at the technologically important visible to ultraviolet spectrum still remain elusive. Here, these important problems are tackled by experimentally demonstrating and theoretically verifying spectrally tunable, extremely large, and broadband chiroptical response by nanohelical metamaterials. The reported new designs of all‐dielectric and dielectric‐metallic (hybrid) plasmonic metamaterials permit the largest and broadest ever measured chiral Kuhn's dissymmetry factor achieved by a large‐scale nanophotonic structure. In addition, the strong circular dichroism of the presented bottom‐up fabricated optical metamaterials can be tuned by varying their dimensions and proportions between their dielectric and plasmonic helical subsections. The currently demonstrated ultrathin optical metamaterials are expected to provide a substantial boost to the developing field of chiroptics leading to significantly enhanced and broadband chiral light‐matter interactions at the nanoscale. [ABSTRACT FROM AUTHOR]

Self-assembled structures with circularly polarized luminescence (CPL) have attracted great attention in recent years. π-conjugated N-terminal amino acids with chiral amino acid residues and luminophores are capable of forming selfassembled structures at hierarchical levels, whereby chirality can be transferred to the macroscopic scale with easily modulated CPL properties. Due to the presence of multiple noncovalent binding sites, including hydrogen bonding and aromatic interactions, π-conjugated N-terminal amino acids are emerging core candidates for incorporation into multicomponent self-assembled architectures, accomplishing rational control over supramolecular chirality as well as showing rich chiroptical properties. In this Minireview, we provide a brief summary of multiple-component coassembled systems comprising π-conjugated N-terminal amino acids, small organic species and metal ions. The synthesis of helical structures and manipulation of supramolecular chirality by controlling the selfassembled species is introduced, and the CPL properties of multiple-component π-conjugated N-terminal amino acids are also briefly summarized. [ABSTRACT FROM AUTHOR]

Protein allostery, a chemical‐to‐mechanical effect that can precisely regulate protein structure, exists in many proteins. Herein, we demonstrate that protein allostery can be used to drive self‐assembly for the construction of tunable protein architectures. Calmodulin (CaM) was chosen as a model allosteric protein. Ca2+‐mediated contraction of CaM to a closed state can activate CaM and its ligand to self‐assemble into a 1D protein helical microfilament. Conversely, relaxation of CaM to the open state can unwind and further dissociate the helical assemblies. Fine regulation of the protein conformation by tuning the external Ca2+ level allows us to obtain various protein helical nanostructures with tunable helicity. This study offers a new approach toward chemomechanically controlled protein self‐assembly. [ABSTRACT FROM AUTHOR]

Among various metal oxide semiconductors, hematite ( α-FeO) is a considerable candidate for solar energy applications due to its moderate bandgap, good chemical stability and lower cost. However, hematite has a low diffusion length of charge carriers and low photocurrent generation efficiency restricting its widespread applications. In this work, we have studied the improvement of light absorption properties of a hematite thin film by adjoining the film by an array of silver helical nanostructures. Different forms of normal and conical nanohelices are fabricated using glancing angle deposition method. The helical nanostructures are fixed to a substrate and then are covered by a thin film of hematite nanoparticles. Measurement of UV-Vis spectra of the fabricated thin films indicates the remarkable broadband enhancement of the light absorption properties in the visible and near infrared regions. The improvement is more broadband for conical nanohelices than the normal ones. The experiments have also been supplemented by consistence finite element numerical calculations. Both the experiment and the simulation confirm improvement of the light absorption of the hematite thin film by about 45 and 52 % using normal and helical Ag nanostructures, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • Electro-optical effects in liquid crystal helical nanostructures are analyzed. • Achievements to create liquid crystals with subwavelength helix pitch are emphasized. • Advantages of helical liquid crystals for use in photonic devices are underlined. • The unsolved problems in physics of helical smectic liquid crystals are mentioned. The origin of ferroelectricity in smectic liquid crystals is attributed to the chirality of their molecules. The chirality reduces the space symmetry and leads to the helical (helicoidal) spatial distribution of molecular axes in ferroelectric and antiferroelectric liquid crystals (FLCs and AFLCs), called a helical structure, or helical nanostructure, if its period is much less than any wavelength of visible light. Deformations of FLCs and AFLCs helical structures under the applied electric field E lead to the emergence of a number of specific electro-optical effects. This review analyzes the main results of experimental and theoretical studies of various electro-optical manifestations of FLCs and AFLCs helical nanostructures deformations, which are already used to develop displays and photonic devices of a new generation. [ABSTRACT FROM AUTHOR]

Self-assembly of chiral amphiphiles with π-conjugated tectons into one-dimensional helical nanostructures offers great potential applications in the biological, physical, and material sciences. In this review, the recent development of supramolecular self-assembly of chiral amphiphiles with π-conjugated tectons has been discussed on the basis of experimental exploration by elegantly utilizing cooperative noncovalent forces such as π-π stacking, hydrophobic interaction, hydrogen bond and electrostatic interaction, and the potential applications of these self-assembled helical nanostructures in chiral recognition, asymmetric catalysis, electrical conduction, switchable interfaces and soft template for the fabrication of one-dimensional hard materials are described by a representative example. Meanwhile, some scientific and technical challenges in the development of supramolecular self-assembly of chiral amphiphiles with π-conjugated tectons are also presented. It is hoped that this review can summarize the strategies for self-assembling soft nanomaterials by using chiral amphiphiles with π-conjugated tectons, and also as a guideline for design functional nanomaterials for various potential applications. [ABSTRACT FROM AUTHOR]

Abstract: One achiral molecule of thioxanthone–anthracene (TX-A) is able to self-assemble into chiral nanowires by tuning the solvent with different polarity. Left- and right-handed nanowires with helix structure can be produced from chloroform and acetic ester solution of TX-A respectively. The SEM and TEM images confirm the formation of the helical nanowires. The results indicate that the solvent polarity has great influence in controlling of the self-assembly of organic molecules. The growth process demonstrates a promising pathway to investigate the self-assembling from achiral organic molecules to chiral aggregations. [Copyright &y& Elsevier]

In this study, we have investigated the effect of thickness on the structural and optical properties of copper (Cu) helical nanostructures. Thin films with thicknesses of 160 nm, 280 nm, 450 nm, and 780 nm were obtained by e-beam glancing angle deposition. The morphology and the microstructure were studied by field emission scanning electron microscopy, x-ray diffraction and transmission electron microscopy, while for the optical analysis measurements spectroscopic ellipsometry was used. The results show that the deposited structures are porous with nanometer-sized crystallites preferentially oriented along (111) planes, as well as that the diameter of the helices increases with thickness. Detailed analyses of optical properties have demonstrated that the dielectric function of Cu structures is greatly influenced by the films thicknesses. With increasing thickness from 160 nm to 780 nm, the surface plasmon resonance peak was shifted from 1.31 eV to 1.05 eV, which was correlated with the growth mechanism and the size of deposited nanostructures., (© 2022 IOP Publishing Ltd.)

Helical Nanostructures: Broadband Enhanced Chirality with Tunable Response in Hybrid Plasmonic Helical Metamaterials (Adv. Funct. In article number 2010329, Ufuk Kilic, Christos Argyropoulos, and co-workers tackle these important problems by experimentally demonstrating and theoretically verifying spectrally tunable, extremely large, and broadband circular dichroism from new hybrid dielectric and plasmonic nanohelical metamaterial configurations operating at the technologically important visible to ultra-violet spectrum. Keywords: chirality; helical nanostructures; metamaterials; plasmonics EN chirality helical nanostructures metamaterials plasmonics 1 1 1 05/20/21 20210517 NES 210517 Chiral light-matter interactions have an extremely weak nature, are difficult to be controlled and enhanced, and cannot be made tunable or broadband. [Extracted from the article]

• Helical polyphenyl nanostructures were formed on carbon nanotubes through self-assemble process. • A core-shell structure was formed finally. • The interactions between different halogenated benzene polymer and carbon nanotube were also studied. In this manuscript, helical polyphenyl (PP) nanostructures were formed on single-wall carbon nanotubes (SWCNT) through self-assemble process which was investigated by a molecular dynamics simulation. The results displayed that the linear polyphenyl changed into helical structure and finally a core–shell structure was formed. The formation mechanism of whole process was also exhibited. Furthermore, some influence factors such as the initial angle between polyphenyl chain and nanotube axis, the diameter of carbon nanotube were also displayed. Moreover, the interactions between different halogenated benzene polymer and carbon nanotube were also studied. The new geometrical structures between polyphenyl and single-wall carbon nanotubes may attract more attention in chemical functionalization and helical polymer synthesis, which may be helpful for fabricating nanoscale devices. [ABSTRACT FROM AUTHOR]

• Multiple helical nanostructures are formed which are induced by the boron nitride nanotubes. • The chain number of polyacetylene influences the final configuration of polymer. • Some other influence factors are also displayed. In this manuscript, a molecular dynamics simulation was used to investigate the formation process of multiple helical nanostructures which was induced by the boron nitride nanotubes. The results displayed that three chains of polyacetylene changed to helical nanostructures in the boron nitride nanotube through self-assemble process. The combined action of the van der Waals potential well and the π–π stacking interaction between the polyacetylene and the inner surface of boron nitride nanotubes results in the formation of helical nanostructures. The chain number of polyacetylene influences the final configuration of polymer. Furthermore, some other influence factors such as the diameter of boron nitride nanotube and the length of polymer were also displayed. The new geometrical structures between polyacetylene and boron nitride nanotubes may attract more attention in chemical functionalization and helical polymer synthesis, which may be helpful for fabricating nanoscale devices. [ABSTRACT FROM AUTHOR]

We report a large chiro-optical response from a nanostructured film of aperiodic dielectric helices decorated with ellipsoidal metal nanoparticles. The influence of the inherent fabrication variation on the chiro-optical response of the wafer-scalable nanostructured film is investigated using a computational model which closely mimics the material system. From the computational approach, we found that the chiro-optical signal is strongly dependent on the ellipticities of the metal nanoparticles and the developed computational model can account for all the variations caused by the fabrication process. We report the experimentally realized dissymmetry factor ∼1.6, which is the largest reported for wafer scalable chiro-plasmonic samples till now. The calculations incorporate strong multipolar contributions of the plasmonic interactions to the chiro-optical response from the tightly confined ellipsoidal nanoparticles, improving upon the previous studies carried in the coupled dipole approximation regime. Our analyzes confirm the large chiro-optical response in these films developed by a scalable and simple fabrication technique, indicating their applicability pertaining to manipulation of optical polarization, enantiomer selective identification and enhanced sensing and detection of chiral molecules., (© 2021 IOP Publishing Ltd.)

Photocharge generation and formation of long-lived charge carriers are relevant in photosynthesis, photocatalysis, photovoltaics, and organic electronics. A better understanding of the factors that determine these processes in synthetic polymer semiconductors is crucial, but difficult due to their morphological inhomogeneity. Here, we report the formation of exceptionally long-lived photocharges in one-dimensional organic semiconductor nanostructures. These nanostructures consist of chiral oligopeptide-substituted thienothiophene-based chromophores and exhibit a well-defined helical arrangement of these chromophores at their core. The chromophores give rise to spectroscopic H-aggregates and show strong intermolecular excitonic coupling. We demonstrate that all of these parameters are the prerequisites required for the nanostructures to show the efficient formation of polaron-like photocharges upon irradiation with a low-power white light source. The observed charge carriers in the helical nanowires show an unusually long lifetime on the order of several hours and are formed at high concentrations of up to 3 mol % in the absence of any dedicated electron acceptor. They are observed in solution as well as in film and furthermore give rise to a light-induced increase of the macroscopic charge transport. By contrast, no such photocharge generation is observed either in non-aggregating reference systems of the same chromophores or in aggregated but non-helical systems that do not form one-dimensional nanostructures. Our results thus demonstrate a clear correlation between nanoscopic confinement and the generation of long-lived photocharges.