Self-assembled Templates Research Articles

Multi-strategy for constructing Z-scheme porous hollow double-shell Fe2O3@Ov-NiFe2O4 nanorods-arrays photocathode: Bias-free synthesis of H2O2, Zn-H2O2 cell and generation of NaZnPO4

The rational design of highly active and cost-effective catalysts for the photoelectrocatalytic H2O2 production plays a crucial role in the development of sustainable energy. An in situ self-assembly template and coupling strategy are demonstrated to design a novel porous hollow double-shell Fe2O3 @Ov-NiFe2O4 with enriched oxygen vacancies and a strongly coupled interface (PDS-Fe2O3 @Ov-NiFe2O4-HR) for producing chemical value-added product and constructing rechargeable Zn-H2O2 batteries. As-resultant Z-scheme PDS-Fe2O3 @Ov-NiFe2O4-HR, by improving light utilization efficiency, redox ability and interfacial charge separation efficiency has fast interfacial carrier transport and low electrochemical resistance, thus kinetically promoting PEC can sustain high H2O2 production rates (6.3 mM h−1). Furthermore, the combined configuration of PDS-Fe2O3 @Ov-NiFe2O4-HR-Ti and Fe2O3-Ti enable the production of H2O2 on both electrodes under an external bias-free condition. Zn-H2O2 cells can also provide sufficient power to a light-emitting diode. This rational design strategy provides a new path for constructing highly efficient heterostructure catalysts on energy-related devices.

Disordered Phase-Assisted Growth of Organic Semiconductor Crystals on Self-Assembled Monolayer Templates.

Achieving high mobility and bias stability is a challenging obstacle in the advancement of organic thin-film transistors (OTFTs). To this end, the fabrication of high-quality organic semiconductor (OSC) thin films is critical for OTFTs. Self-assembled monolayers (SAMs) have been used as growth templates for high-crystalline OSC thin films. Despite significant research progress in the growth of OSC on SAMs, a detailed understanding of the growth mechanism of the OSC thin films on a SAM template is lacking, which has limited its use. In this study, the effects of the structure (thickness and molecular packing) of SAM on the nucleation and growth behavior of the OSC thin films were investigated. We found that disordered SAM molecules assisted in the surface diffusion of the OSC molecules and resulted in a small nucleation density and large grain size of the OSC thin films. Moreover, a thick SAM with disordered SAM molecules on the top was found to be beneficial for the high mobility and bias stability of the OTFTs.

Oxygen vacancy-rich C/Ti3C2/(001)TiO2 hollow microspheres and the photocatalytic degradation of organic pollutants

C/Ti3C2/(001)TiO2 hollow microspheres were prepared by combining the template method, self-assembly and hydrothermal method. Anatase TiO2 nanosheets with rich oxygen vacancies formed on the microspheres and exposed active (001) facets due to the spherical surface. TC was removed 92.3% by C/Ti3C2/(001)TiO2-HMs within 160 min, 28.4% by TiO2 and 49.5% by (001)TiO2/Ti3C2 under the same condition. The high removal efficiency of C/Ti3C2/(001)TiO2-HMs could be because the oxygen vacancies exposed on the surface of (001)TiO2 afforded more active sites, extended the light absorption range and promoted the generation of electron-hole pairs. The composite C/Ti3C2/(001)TiO2 structure could suppress the recombination of electron-hole pairs and prolong their lifetime. The degradation pathway of TC was discussed. The TC removal efficiency of C/Ti3C2/(001)TiO2-HMs was confirmed by treating the wastewater from the Slender West Lake. The production principle of oxygen vacancy could be used for preparing MXene composites with excellent catalytic properties and the C/Ti3C2/(001)TiO2-HMs could be a potential choice for treating wastewater.

Organic–Inorganic Nanocomposites of Aspergillus terreus Extract and Its Compounds with Antimicrobial Properties

Due to its distinct, atypical features and possible applications, three-dimensional (3D) hierarchical nanoflowers have sparked considerable interest. Copper (II) ions were employed as inorganic components in this study, whereas various extracts from Aspergillus terreus and their extracted main components were used as organic components. Extracts from A. terreus and its isolated principal component molecules can first form complexes with copper ions, and these complexes subsequently become nucleation sites for primary copper phosphate crystals, showing interactions using an easy and successful self-assembly template synthesis technique. Therefore, the process results in the formation of 3D nanoflowers among the A. terreus extract and its remoted important additives in addition to copper ions, ensuing in a completely unique round flower-like shape containing loads of nanopetals under the most excellent conditions along with pH, attention of organic–inorganic additives, temperature, and the quantity of copper nitrate on nanoflower formation. Furthermore, A. terreus and its isolated major components, Cu3(PO4)2 nanoflowers, seemed to have a remarkable antibacterial effect. Our findings highlight the benefits of nanoflowers made with A. terreus and its isolated secondary metabolites of inorganic structures, which could be used in industrial biocatalysts, biosensors, and environmental chemistry.

Design of hierarchically porous Zr-MOFs with reo topology and confined PMA for ultra-efficient oxidation desulfurization

It is challenging but desirable to synthesize hierarchically porous MOFs (HP-MOFs) with well-defined topology. Herein, a series of HP-Zr-MOFs (H-UiO-66-X) with different topologies were synthesized through an in situ self-assembly template strategy. Further, H3PMo12O40 (PMA) was dispersed within H-UiO-66-X to illustrate the confinement effect of HP-MOFs on PMA as ultra-efficient ODS catalysts. Potentiometric acid–base titration is used to evaluate three typical types of Brønsted acid protons (μ3–OH, Zr-OH2, and Zr-OH) presented in the nodes of defect HP-MOFs according to their different pKa values (∼3, ∼6 and ∼8). By quantifying the amount of defect sites (Zr-OH2 and Zr-OH) resulting from either missing Zr6O8 clusters or missing linkers in the HP-MOFs, the information about the true topology of HP-MOFs is provided. The Zr-OH2 defects are correlated to missing Zr6O8 cluster and the Zr-OH defects are related to missing linkers. The loaded PMA molecules mainly occupy the Zr-OH2 defect sites by the substitution of H2O molecules and still maintain the Keggin structure. The results give deep insight on the structure-activity relationship for PMA confined in HP-Zr-MOFs with clear topologies.

Gelatin Matrix as Functional Biomaterial for Immobilization of Nanoparticles of Metal-Containing Compounds.

The data concerning the synthesis and physicochemical characteristics of specific functional biomaterials-biopolymer-immobilized matrix systems based on gelatin as an array and chemical compounds, which include atoms of various metal elements-are systematized and discussed. The features of this biopolymer which determine the specific properties of the immobilized matrix systems formed by it and their reactivity, are noted. Data on gelatin-immobilized systems in which immobilized substances are elemental metals and coordination compounds formed as a result of redox processes, nucleophilic/electrophilic substitution reactions, and self-assembly (template synthesis), are presented. The possibilities of the practical use of metal-containing gelatin-immobilized systems are promising for the future; in particular, their potential in medicine and pharmacology as a vehicle for "targeted" drug delivery to various internal organs/tissues of the body, and, also, as potential biosensors is noted.

Breaking sensitivity limits of QCM-D: An integrated nano-honeycomb sensor for characterization molecular interactions with lipid bilayers.

In the last few years Quartz Crystal Microbalance with Dissipation (QCM-D) emerged as an indispensable label-free method for monitoring formation of lipid bilayers on surfaces and assessing quality of the bilayers formed. QCM-D provides time-resolved data on mass and viscoelastic properties of molecular layers at the sensor surface and therefore is suitable for detecting vesicle adhesion, rupture, and spreading to form planar surface-supported bilayers. However, the small surface areas of QCM sensors impose severe limitation on mass sensitivity of the method. This is, perhaps, the main reason why QCM-D is rarely employed for studying lipid bilayer phase transitions and membrane binding events. To overcome these limitations, we have integrated the QCM sensor with an array of rigid honeycomb-packed anodic aluminum oxide (AAO) nanopores of ca. 25-80 nm in diameter and 2-10 μm in length by anodizing aluminum film deposited on the electrode surface. The resulting nanostructured QCM sensor increased surface area and improved sensitivity of the method by >100-fold. AAO-QCM electrode also provided a nanoscale template for self-assembly of lipid bilayers into nanotubular structures without any chemical attachment. We then employed such nanopore-confined bilayers to observe the main and more difficult to characterize pre-transition of membranes prepared from either pure 1,2-dimyristoyl-sn-glycerol-3-phosphocholine (DMPC) or 1,2-dipalmitoyl-sn-glycerol-3-phosphocholine (DPPC) lipids. Observed changes in QCM frequency reflected variations in lipid density upon phase transitions and occurred at temperatures in agreement with literature data. The signal-to-noise ratio of the phase transition peaks increased by 300-fold when compared to conventional QCM-D sensors. To further explore potential applications of AAO-QCM-D, ethanol-induced biphasic effects of phospholipid bilayers were studied. High sensitivity of AAO-QCM electrodes makes the method highly attractive for developing biosensing applications based on detecting changes in lipid packing at the nanoscale.

Impact of self-assembled monolayer templates on electrodeposition of Pt particles

Active templating is commonly used to fabricate nanoparticles. We have demonstrated that self-assembled monolayers (SAMs) on gold can be employed as active templates for nanoparticle synthesis. This work further expands the use of active template by evaluating the effect of thiol terminal groups (CH3, COOH and OH) and their chain lengths (C6, C10/C11 and C16) on electrochemical Pt particle growth. The result suggests that the size, distribution and the potential difference (ΔEdep = ELOP - EFOP) between the first observable peak (EFOP) and the last observable peak (ELOP) in the cathodic region, are strongly affected by the terminal groups and their hydrophilicity/hydrophobicity. Methyl terminal groups lead to the expected ΔEdep > 0, but surprisingly resulted in an increase in the particle count with a decrease in the average particle size with increasing thiol length. Both hydrophilic terminal groups demonstrated ΔEdep < 0 with the expected decrease in particle count with an increase in their size by increasing the thiol chain length. The results suggest thiol motion and hydrophobicity significantly influence particle growth behaviour.

DNA-templated self-assembly of bradykinin into bioactive nanofibrils.

Bradykinin (BK) is a peptide hormone that plays a crucial role in blood pressure control, regulates inflammation in the human body, and has recently been implicated in the pathophysiology of COVID-19. In this study, we report a strategy for fabricating highly ordered 1D nanostructures of BK using DNA fragments as a template for self-assembly. We have combined synchrotron small-angle X-ray scattering and high-resolution microscopy to provide insights into the nanoscale structure of BK-DNA complexes, unveiling the formation of ordered nanofibrils. Fluorescence assays hint that BK is more efficient at displacing minor-groove binders in comparison with base-intercalant dyes, thus, suggesting that interaction with DNA strands is mediated by electrostatic attraction between cationic groups at BK and the high negative electron density of minor-grooves. Our data also revealed an intriguing finding that BK-DNA complexes can induce a limited uptake of nucleotides by HEK-293t cells, which is a feature that has not been previously reported for BK. Moreover, we observed that the complexes retained the native bioactivity of BK, including the ability to modulate Ca2+ response into endothelial HUVEC cells. Overall, the findings presented here demonstrate a promising strategy for the fabrication of fibrillar structures of BK using DNA as a template, which keep bioactivity features of the native peptide and may have implications in the development of nanotherapeutics for hypertension and related disorders.

Unraveling the impact of template geometry and confinement on template-assisted self-assembly of nanoparticles

In templated self-assembly, nanoparticles are slotted far from and ahead of the receding contact line.

Macroporous SnO2/MoS2 inverse opal hierarchitecture for highly efficient trace NO2 gas sensing.

The innovation of NO2 gas sensors is highly desirable in environmental monitoring and human safety. Herein, a macroporous SnO2/MoS2 inverse opal hierarchitecture has been constructed with substantial interface charge transfer, which realizes the efficient and stable detection of NO2 with an enhanced response, fast kinetics, and high selectivity at low temperatures.

Development of Nanocolloidosome Based Formulations and Characterization

Microencapsulation, 30 year old field is still growing with development of new materials and active ingredient. Encapsulation is an imperative technology used to deliver the component to targeted site in an intact manner with no effect from surrounding environment. Colloidosome a novel class of microcapsule generated from the concept Pickering emulsion which is used for production of microcapsule by fixing the particle assembly at interface. Colloidosomes are hollow spherical capsule developed from controlled self-assembly of colloidal particles on emulsion droplets which reduces total interfacial energy and stabilize the structure. In this droplet act as templates for self-assembly of colloidal particles which develops stable form as per their shapes, surface properties, mass and electrical charge. Different types of emulsions are used to develop the various colloidosomes such as aqueous colloidosomes, hairy colloidosomes, nanoparticle colloidosomes, layer by layer colloidosomes and non-spherical colloidosomes. Structural characterization exhibited that the colloidosomes are most stable structure and intrinsic porosity of colloidosomes can be used for controlled and targeted drug delivery. Study of packing of particle and 3D image revealed the presence of hexagonal and pentagonal patch like soccer ball and C60 fullerenes on the surface of colloidosomes which gives stability without collapsing the structure. Increase in concentration of small particle increases attraction between the colloidosome that causes flocculation. Stability of colloidosomes affected by time required for saturation of large particle. Applications of colloidosomes are mainly useful as encapsulating agent and in controlled drug delivery. Colloidosomes are also valuable in tumor therapy, antifungal, antimicrobial therapy and in DNA delivery. The flexibility in formulation of colloidosomes will be helpful in various applications in future.

Self-assembly assisted by microdroplet templates confinement for the preparation of ultramixed composite energetic particulates

Restricted by the macroscopic spatial scale conditions in traditional preparation methods, the improvement of delay precision of the delay composition gradually arrives at the bottleneck. Therefore, a microdroplet-confined coupling polymer self-assembly theory based on microfluidics was proposed to prepare ultramixed self-assembled composite energetic material particulates in order to make a breakthrough in its delay precision. Taking boron (B)/barium chromate (BaCrO4) delay composition as the research object, nano-BaCrO4 particles were prepared and microdroplet templates were generated by using the micromixing and microdispersing reaction systems respectively. With the excellent mixing efficiency of the micromixing reaction system, the effect of reactant concentration and temperature on crystal morphology and particle size of BaCrO4 was investigated, and the spectral response of BaCrO4 particles was analyzed on-line by using an on-line UV–vis spectrophotometer. The results indicated that the reactant concentration exerted a great influence on crystal morphology and particle size of BaCrO4, and the characteristic absorption peak of BaCrO4 was red-shifted regularly with the decrease of crystal thickness at low reactant concentration. Microdroplet templates for self-assembly of B/BaCrO4 nano-composite particles were generated by using a microdispersing reaction system, and the self-assembled B/BaCrO4 particulates were prepared. The particulates were characterized by thermal analysis and the delay precision was measured. The results exhibited that the composite energetic particulates with ultra-homogeneous mixing, excellent combustion performance and high delay precision were prepared. In summary, in this study, ultramixed self-assembled B/BaCrO4 particulates with high delay precision were prepared based on microfluidics, which can provide a novel technology and method for the preparation and mixing of other composites.

Gd3+ ionic nano-aggregate clusters enable metallopolymers redox electrolytes as high-performance flexible radiation shielding

In this work, Gd3+ ionic nano-aggregate clusters were introduced into metallo-polyelectrolytes to balance the conflicts between high mechanical robustness and X-ray attenuation of flexible shielding materials. The segmented polyurethanes (PUs) containing main-chain bisferrocene and pendant sulfonates in hard segments is applied as a macromolecular template for the subsequent self-assembly with Gd3+. Rare earths aggregate into dynamic clusters about 2.2 nm, which is beneficial to improve the radiation attenuation ability and mechanical properties of materials. The hierarchical noncovalent interactions (ionic interactions, coordination interactions, hydrogen bonds, and ferrocene-metal interactions, etc.) in the aggregate PUs enable the co-existence of high mechanical strength, large stretchability, and fast radiation dissipation. As a result, this Gd3+ hybrid bisferrocene-based PU demonstrates extremely high tensile properties (breaking stress = 27.8 ± 0.2 MPa, breaking strain = 576 ± 7%) as well as super atomic shielding efficiency (14.39 cm2 g−1) at 65 keV.

Control on Pt-containing ordered honeycomb mesoporous nanostructures via self-assembly of block copolymer

Control on the mesoporous nanostructures with uniform-sized and well-arranged mesopores can provide enhanced surface areas and mechanical properties, which are preferred for the development of energies, sensors, and electro-optical devices. Herein, Pt-containing ordered honeycomb (Pt/OHC) nanocomposites with regularly arranged mesopores were synthesized via self-assembly of polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) block copolymers (BCPs), following mechanism study of morphological evolution, concept of structural control, potential in catalyst application, and exploration of various metals. Particularly, it was found that the self-assembly of BCP directed the ordered arrangement of the mesopores, whereas the P4VP blocks incorporated Pt and precisely positioned it on the pore walls and on the outer surface of the honeycomb matrix. Mono- to multi-layered Pt/OHCs could be generated by controlling the thicknesses of the self-assembled pristine templates, and the average diameters of the mesopores could be varied from 12 nm to 40 nm by tuning the PS:P4VP block mass ratios. The obtained Pt/OHC demonstrated promising application as electrocatalysts in hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR), for which an overpotential of 39 mV at current density of 10 mA/cm2 (η10) and a high half wave potential (E1/2) of 0.87 V (vs. RHE), respectively, were observed in acidic media. In addition, the strategy developed here could be expanded for other metals, such as Au and Ir, to be incorporated into the ordered honeycomb matrix, providing a robust method to synthesize metal-containing mesoporous nanomaterials. With this work, we aim to offer an insight of designing ordered mesoporous nanocomposites, a concept of control over the mesoporous nanostructures, and a potential for their application in electrocatalysts.

Fabrication of a humidity-resistant formaldehyde gas sensor through layering a molecular sieve on 3D ordered macroporous SnO2 decorated with Au nanoparticles

The development of highly-sensitive and moisture resistant semiconductor metal oxide (SMO) gas sensors for practical application remains a challenge. Here, a three-dimensional ordered macroporous (3DOM) SnO2 decorated with Au nanoparticles (NPs) was obtained via a facile self-assembly template method and the Au content was optimized. The resulting 3DOM Au/SnO2 gas sensor displayed remarkable performance, with its response and lower actual detection limit to formaldehyde 10.2 times higher and 500 times lower, respectively, compared to the undecorated 3DOM SnO2 sensor at 110 °C. Meanwhile, the fast response-recovery process and the repeatability, stability, and selectivity of the sensor indicate that it can meet the requirements for practical application. Density functional theory (DFT) calculations revealed that the Au/SnO2 NPs have strong adsorption energies and electrical conductivity, allowing for selective formaldehyde detection. Further, the 3MCM-48 layer protects the 3DOM Au/SnO2 layer from moisture, allowing at least 80 % of the initial response value to formaldehyde to be maintained even at> 90 % relative humidity. Hence, the proposed strategy represents, for the first time, a universal and effective way to achieve high response and moisture-resistant formaldehyde sensors and demonstrates the potential of SMO gas sensors for indoor air monitoring.

The synergistic effect of polytetrafluoroethylene in-situ fibrillation and dibenzoyl sebacate hydrazide on the crystallization and foaming behavior of poly (lactic acid)

The fully degradable poly (lactic acid) foam with green environmental protection characteristics can alleviate the shortage of petroleum resources caused by the application of plastics. However, due to the inherent low melt strength and slow crystallization rate of linear PLA. It is difficult to obtain PLA microcellular foam with good morphology. In order to obtain PLA microcellular foam with ultra-high expansion ratio and small cell size, PTFE (polytetrafluoroethylene) nanofibers with excellent CO2 adsorption rate were introduced. Self-assembled nucleator TMC-300(dibenzoyl sebacate hydrazide) was also introduced to blend with PLA to obtain small-sized cells. The results show that the PTFE entanglement network as a self-assembled template can effectively improve the early crystallization nucleation efficiency and increase the crystallinity of branched PLA (CBPLA)/TMC by 7 %. The microcellular foam with PTFE content of 0.5 wt% (CBPLA/TMC/PTFE 0.5) was successfully prepared by physical foaming agent, which had the lowest cell size (8.7 μm) And high expansion ratio (1200 %).

Morphology manipulation of silica nanoparticles via the catalytic templates reaction system

In this study, we have developed a synthetic method which can precisely and conveniently manipulate the morphologies of silica nanoparticles at the molecular level. The reaction system contains cationic cetyltrimethylammonium bromide (CTAB), fatty acid salts, modulating molecules, silica precursor, and water. No additional alkaline catalysts and organic solvents are needed. Fatty acid salts, acting as the catalytic co-surfactants and the shaping agents as well, form uniform self-assembly templates with cationic CTAB. All the synthetic silica nanoparticles are characterized using TEM, SEM and N 2 sorption experiments. Results show that the generated nanoparticles are highly dispersed and demonstrate a variety of surface morphologies such as solid, porous, spokewise, sponge-like, walnut-like, Swiss roll-like appearance. The morphology transitions can be tuned by changing the aliphatic lengths (C2 to C18) of catalytic fatty acid salts, the concentration of silica precursor, and the combination of the fatty acid salts with different carbon chains. In the case of all the porous nanoparticles, the pore size (from ∼2.5 nm to > 100 nm, from single-pore type to dual-pore type) can be obtained by the adjustment of above parameters. In addition, the silica nanoparticles can also be transformed to extremely small granulates（∼8 nm to the lowest）and hollow shells via introducing specific compounds (called modulating molecules) that regulate the molecular interactions within the reaction system. The developed reaction system is environment-friendly. The current work could be applied to the engineering of preparing other nanomaterials via the sol-gel method.

Hollow polypyrrole nanorods via molecular aggregates sacrificial strategy for broadband electromagnetic waves absorption

Polypyrrole (PPy) has aroused great interest due to its excellent physicochemical properties in recent years, especially in the area of electromagnetic wave absorption (EMA). A large number of researches have shown that the regulation of micromorphology has great influence on the EMA performance. Compared with other micromorphology, the hollow structure can significantly promote the EMA performance. In this study, we fabricated hollow PPy (HPPy) nanorods using self-assembly template that can be removed easily. The results show that the dielectric constant of HPPy can be controllably adjusted by tuning the wall thickness, and the HPPy exhibits better EMA performance than the shapeless PPy. Specifically, the minimum reflection loss (RL) can reach − 54.94 dB, and the largest effective absorption bandwidth (EAB) reaches 7.36 GHz under filler loading ratio of 10 wt%. Impedance matching and multiple scattering are considered to be major factors for the improvement of EMA property. This research gives a general method for the preparation of novel hollow electromagnetic absorbing materials.

DNA-POINT: DNA Patterning of Optical Imprint for Nanomaterials Topography.

Engineering well-defined scale-spanning structures through transfer of diverse biomolecules and materials to a surface is of tremendous interest in life sciences research yet remains profoundly challenging. Here, we report a novel method, termed as DNA patterning of optical imprint for nanomaterials topography (DNA-POINT), for rapid photopatterning of large area, geometrically complex surfaces via light-responsive DNA. Our method employs top-down multiphoton-driven patterning of azobenzene-modified DNA strands, offering precise position control of molecules and nanoparticles along the axial plane and a template for bottom-up self-assembly of multiple layers of different chemical composition along the vertical plane. We demonstrate the surface patterning of plasmonic gold nanoparticles, fluorophore-labeled oligonucleotides, and multiple layers consisting of molecule-nanoparticle hybrid patterns into preconceived shapes without compromising on the functionality of the biomolecules. Furthermore, we exhibit scanning mode operation of DNA-POINT, thereby paving the way for maskless and cleanroom-free fast fabrication of biochips for high-throughput diagnostics and biosensing applications.