The self-assembly of clusters in inorganic systems is an interesting subject. The self-assembly of big molecules has been well established in biological systems. In addition, the coordination chemistry of metal-sulfur...The self-assembly of clusters in inorganic systems is an interesting subject. The self-assembly of big molecules has been well established in biological systems. In addition, the coordination chemistry of metal-sulfur-nitrogen cluster complexes has been a very active and attracting field for many years as a result of the novelty and versatility of the crystal structures and reactivities of such clusters, as well as their potential applications as the models for the active sites in non-heme proteins. At the same time, there is currently considerable interest in the formation of metal complexes with heterocyclic ligands because of the diverse characteristics of ligands and their consequential wide range of applications.展开更多
The polymerization of amphiphilic self assemblies is a promising method to synthesize nano structured materials with novel properties. These materials have many attractive features for their application in biomedica...The polymerization of amphiphilic self assemblies is a promising method to synthesize nano structured materials with novel properties. These materials have many attractive features for their application in biomedical area and materials science, such as catalysis, separation, surface modification, and therapeutics areas. A general review on the polymerization of lipids and surfactant self assemblies to amphiphilic self assemblies is given in this paper with 49 references. The polymerization and the subsequently resulted structure of lipids in different morphologies are summarized. The polymerization of polymerizable surfactants(surfmers) in emulsion and liquid crystalline phases are also discussed. The potential application of new nano porous materials is briefly described.展开更多
The layer by layer complexation technique of polymer and metal ion was successfully utilized to fabricate the ultrathin multilayer film of poly(3 thiophene acetic acid (PTAA) and Tb 3+ ion by dipping the subst...The layer by layer complexation technique of polymer and metal ion was successfully utilized to fabricate the ultrathin multilayer film of poly(3 thiophene acetic acid (PTAA) and Tb 3+ ion by dipping the substrates alternatively in polymer and Tb 3+ ion aqueous solutions. UV-vis measurement revealed that the absorbance has linearity with the bilayer number from layer to layer and the X ray photoelectron spectrum (XPS) confirmed the existence of Tb 3+ ion. The pH of both the polymer and TbCl 3 solutions influence the thickness dramatically while the concentration of the solutions is not so sensitive. The luminescent spectrum of the complex film shows the characteristic emission of Tb 3+ ion as well as the ligand indicating the formation of the complex.展开更多
Amphiphilic block copolymers can exhibit rich and complex morphologies in aqueous solutions, but these structures are usually delicate, easily disturbed by composition change or temperature change. In this work, the u...Amphiphilic block copolymers can exhibit rich and complex morphologies in aqueous solutions, but these structures are usually delicate, easily disturbed by composition change or temperature change. In this work, the use of different methods to cross link block copolymer self assemblies in the presence of a selective solvent and to stabilize the structures is reviewed. In addition, the cross linking reaction kinetics of block copolymer amphiphilic self assemblies is briefly discussed.展开更多
Gold nanorods with aspect ratios of from 1 (particles) to 31.6 were synthesized by the seed-mediated method and packed in a highly ordered structure on a large scale on silicon substrates through capillary force ind...Gold nanorods with aspect ratios of from 1 (particles) to 31.6 were synthesized by the seed-mediated method and packed in a highly ordered structure on a large scale on silicon substrates through capillary force induced self-assembly behaviour during solvent evaporation. The gold nanorod surface exhibits a strong enhancing effect on Raman scattering spectroscopy. The enhancement of Raman scattering for two model molecules (2-naphthalenethiol and rhodamine 6C) is about 5-6 orders of magnitude. By changing the aspect ratio of the Au nanorods, we found that the enhancement factors decreased with the increase of aspect ratios. The observed Raman scattering enhancement is strong and should be ascribed to the surface plasmon coupling between closely packed nanorods, which may result in huge local electromagnetic field enhancements in those confined junctions.展开更多
This study investigated the stability behaviour of molecular monolayer symmetric chemically modified tetraether lipids caldarchaeol-PO<sub>4</sub> on the amino-silanised silicon wafer using Langmuir-Blodge...This study investigated the stability behaviour of molecular monolayer symmetric chemically modified tetraether lipids caldarchaeol-PO<sub>4</sub> on the amino-silanised silicon wafer using Langmuir-Blodgett films, Self Assembling Monolayers (SAMs), ellipsometry, and atomic force microscopy (AFM). The monolayers of caldarchaeol-PO<sub>4 </sub>were stable on the solid surface amino-silanised silicon wafer. The organizations of molecular monolayers caldarchaeol-PO<sub>4</sub> by Langmuir-Blodgett method and SAMs have been analyzed. The surface of pressure in Langmuir-Blodgett processing is carried out monolayers caldarchaeol-PO<sub>4</sub> more flat island inhomogeneous. Another method of monolayers caldarchaeol-PO<sub>4</sub> by SAMs is showed a large flat domain. Monolayers caldarchaeol-PO<sub>4</sub> by Langmuir-Blodgett method seems to be stable and chemically resistant after washing with organic solvent and an additional treatment ultrasonification with various thickness lipids arround 2 nm to 6 nm. Conversely, monolayer caldarchaeol-PO<sub>4</sub> by SAMs appears fewer than monolayers caldarchaeol-PO<sub>4</sub> by Langmuir-Blodgett method, the thickness of various from 1 nm to 3 nm.展开更多
Inorganic NiO_(x) based inverted structure perovskite solar cells (PSCs) is reported to be more stable than that with the organic hole transport materials.In this work,NiO_(x)/MAPbI_(3) interface chemical reaction ind...Inorganic NiO_(x) based inverted structure perovskite solar cells (PSCs) is reported to be more stable than that with the organic hole transport materials.In this work,NiO_(x)/MAPbI_(3) interface chemical reaction induced instability of perovskite is unveiled:Ni^(3+) and I^(-) exhibit redox reactions and deprotonation of MA^(+) happens,which result in interface defects and perovskite lattice deformation.Thus the defective interface accelerates the degradation of perovskite by defect pathways from the bottom interface to the perovskite surface contacting H_(2)O/O_(2).Self-assembled interlayer of NH_(2)^(-)end silane on NiO_(x)separates the reactive NiO_(x)and MAPbI_(3),tunes the interface energy states by–NH_(2) end group.As a result,the PSC based on the silane treated NiO_(x)achieves enhanced PCE of 20.1%with decent stability under environmental and extreme conditions (high temperature,high humidity,light infiltration).Our work highlights the interface chemical problem induced PSC instability and a simple interface modification to achieve the stable PSCs.展开更多
The direct electron transfer of amino oxidase on electrode surface based on self assembly technique occurs at 505 mV( vs . Ag/AgCl), indicating that copper atoms are the electron transfer centers and catalytic cent...The direct electron transfer of amino oxidase on electrode surface based on self assembly technique occurs at 505 mV( vs . Ag/AgCl), indicating that copper atoms are the electron transfer centers and catalytic centers of amino oxidase.展开更多
The self-assembled formation of a one-dimensional lanthanum salicylald imine coordination polymer was proved by the X-ray diffraction analysis of new l anthanum(Ⅲ) nitrate complex containing N,N’-bis(salicylidene)-1...The self-assembled formation of a one-dimensional lanthanum salicylald imine coordination polymer was proved by the X-ray diffraction analysis of new l anthanum(Ⅲ) nitrate complex containing N,N’-bis(salicylidene)-1,5-pentanediami ne ligand(H2L) . It was obtained in situ in a one-step,metal-templated condensa tion of salicylaldehyde with 1,5-pentanediamine(cadaverine,biogenic polyamine) and characterized by microanalysis and spectroscopic(IR,ESI-MS,UV-Vis,and 1 H NMR) data. The [La(NO3) 3(μ-H2L) 2]∞ complex displayed 10-coordinate distorted bicapped dodecahedron geometry with unusual coordination pattern of undeprotonat ed salicylaldimines which acted as μ-bridging ditopic ligands using exclusivel y the oxygens as donor atoms with the nitrogen atoms not being involved in the c oordination environment.展开更多
We demonstrate the self-assembly of solution-processible gold nanoparticles into the nanoholes consisting of patterned substrate through annealing, which facilitates successful fabrication of square lattices of gold n...We demonstrate the self-assembly of solution-processible gold nanoparticles into the nanoholes consisting of patterned substrate through annealing, which facilitates successful fabrication of square lattices of gold nanocylinders with a period of 350 nm, a height of about 200 nm, and an aspect ratio larger than 2.展开更多
Ordered zinc oxide (ZnO) rod arrays with very high orientation were fabricated on Si substrates by using a solution method. The substrate surfaces were functionalized by Self-Assembly Monolayers (SAMs). In the ver...Ordered zinc oxide (ZnO) rod arrays with very high orientation were fabricated on Si substrates by using a solution method. The substrate surfaces were functionalized by Self-Assembly Monolayers (SAMs). In the very early growth stage, the oriented ZnO crystals had already grown, which appeared to be the main reason why ZnO nanorods showed very high orientation. The un-dense and un-uniform SAMs provided a surface that was heterogeneous to ZnO nucleation. Consequently, highly oriented ZnO rods were selectively grown on the "coin-like" SAM-uncovered regions. The route developed here can provide some helpful information to control the nucleation and orientation of ZnO in aqueous solution. Also, the site-selective growth mechanisms can indicate a clue to grow patterned highly oriented ZnO nanorod arrays by the organic template.展开更多
Developing high‐performance adhesive materials not only aims at industrial and social requirements but also bears the fundamental importance of understanding the chemical factors of biological adhesion to develop bio...Developing high‐performance adhesive materials not only aims at industrial and social requirements but also bears the fundamental importance of understanding the chemical factors of biological adhesion to develop biomimetic adhesive materials.Owing to the wide development of supramolecular chemistry,numerous supramolecular tools are exploited and proved to be reliable in the replacement of traditional covalent materials by reversible noncovalent or dynamic covalent materials.Taking advantage of these readyto‐use supramolecular toolboxes,supramolecular adhesive materials are rising and promising toward“smart”adhesives,that is,enabling responsiveness,reversibility,and recyclability.Compared with polymeric adhesive materials,low‐molecular‐weight adhesives feature chemically precise structure,easier engineering by molecular design,and hence higher reproducibility.However,it remains highly challenging to make high‐performance adhesive materials by low‐molecular‐weight feedstocks.This review will focus on the recent advancement in the construction of supramolecular adhesive materials by smallmolecule self‐assembly.The design guidelines and consideration on the molecular scale will be discussed and summarized on how to enhance the strength of adhesives.Meanwhile,owing to the dynamic nature of supramolecular self‐assembly,several“smart”functions of such materials will be presented,such as stimuli–responsiveness and adaptiveness.Finally,current challenges and future perspectives of this emerging field will be proposed.展开更多
Polypropylene(PP) meltblown fibers were coated with titanium dioxide(Ti O2) nanoparticles using layer-by-layer(Lb L) deposition technique. The fibers were first modified with 3layers of poly(4-styrenesulfonic a...Polypropylene(PP) meltblown fibers were coated with titanium dioxide(Ti O2) nanoparticles using layer-by-layer(Lb L) deposition technique. The fibers were first modified with 3layers of poly(4-styrenesulfonic acid)(PSS) and poly(diallyl-dimethylammonium chloride)(PDADMAC) to improve the anchoring of the Ti O2 nanoparticle clusters. PDADMAC, which is positively charged, was then used as counter polyelectrolyte in tandem with anionic Ti O2 nanoparticles to construct Ti O2/PDADMAC bilayer in the Lb L fashion. The number of deposited Ti O2/PDADMAC layers was varied from 1 to 7 bilayer, and could be used to adjust Ti O2 loading. The Lb L technique showed higher Ti O2 loading efficiency than the impregnation approach. The modified fibers were tested for their photocatalytic activity against a model dye, Methylene Blue(MB). Results showed that the Ti O2 modified fibers exhibited excellent photocatalytic activity efficiency similar to that of Ti O2 powder dispersed in solution. The deposition of Ti O23 bilayer on the PP substrate was sufficient to produce nanocomposite fibers that could bleach the MB solution in less than 4 hr.Ti O2-Lb L constructions also preserved Ti O2 adhesion on substrate surface after 1 cycle of photocatalytic test. Successive photocatalytic test showed decline in MB reduction rate with loss of Ti O2 particles from the substrate outer surface. However, even in the third cycle, the Ti O2 modified fibers are still moderately effective as it could remove more than 95% of MB after 8 hr of treatment.展开更多
Inspired by the curved branches of fractal trees, hooked Ni–Fe fibers were grown in situ in Ni–Fe composite coatings on a spheroidal graphite cast iron substrate. These hooked Ni–Fe fibers exhibited inclination ang...Inspired by the curved branches of fractal trees, hooked Ni–Fe fibers were grown in situ in Ni–Fe composite coatings on a spheroidal graphite cast iron substrate. These hooked Ni–Fe fibers exhibited inclination angles of about 39°, which was in accordance with the theoretical prediction of 37°. Ni–Fe nanostructures self-assembled to form dendrites and evolved into hooked fibers by an oriented attachment reaction. The orientation rotation of Ni–Fe nanostructures played an important role in the growth of curved hooked Ni–Fe fibers. During sliding wear tests, the volume loss of the spheroidal graphite cast iron substrate was 2.2 times as large as that of the Ni–Fe coating reinforced by hooked fibers. The good load-transferring ability of hooked Ni–Fe fibers led to an improvement in their wear properties during wear tests.展开更多
Swarm intelligence embodied by many species such as ants and bees has inspired scholars in swarm robotic researches. This paper presents a novel autonomous self-assembly distributed swarm flying robot-DSFR, which can ...Swarm intelligence embodied by many species such as ants and bees has inspired scholars in swarm robotic researches. This paper presents a novel autonomous self-assembly distributed swarm flying robot-DSFR, which can drive on the ground, autonomously accomplish self-assembly and then fly in the air coordinately. Mechanical and electrical designs of a DSFR module, as well as the kinematics and dynamics analysis, are specifically investigated. Meanwhile, this paper brings forward a generalized adjacency matrix to describe configurations of DSFR structures. Also, the distributed flight control model is established for vertical taking-off and horizontal hovering, which can be applied to control of DSFR systems with arbitrary configurations. Finally, some experiments are carried out to testify and validate the DSFR design, the autonomous self-assembly strategy and the distributed flight control laws.展开更多
It had very long been a dream in polymer science to synthesize long multi-block polymer chains with an orderedchain sequence and controllable block lengths. Using ionic or living free radical polymerization or furnish...It had very long been a dream in polymer science to synthesize long multi-block polymer chains with an orderedchain sequence and controllable block lengths. Using ionic or living free radical polymerization or furnishing each end ofpolymer blocks with a reactive functional group, one can only prepare heteropolymer chains with few long blocks, such asdiblock and triblock copolymers. The most plausible result so far was a pentablock copolymer. Recently, using a combinationof polymer physics and synthetic chemistry, we have invented self-assembly assisted polycondensation (SAAP). Thiscommunication reports the results of using this novel. method to connect 10-100 triblock polymer chains together to formlong multi-block heteropolymer chains with an ordered sequence and controllable block lengths.展开更多
Chemical compositions and mierosturcture of mature human tooth enamel were investigated by XRD , FTIR and SEM to further understand the characteristics of tooth enamel. In order to obtain apatite crystals chemically...Chemical compositions and mierosturcture of mature human tooth enamel were investigated by XRD , FTIR and SEM to further understand the characteristics of tooth enamel. In order to obtain apatite crystals chemically and structurally similar to those in tooth enamel, biomimetic way was employed. Self-assembled monolyers terminated with-SO3 H groups were used as deposition substrates and 1.5 SBF ( the concentrations of Ca^2+ and PO4^3- ions 1.5 times ttum those in simulated body fluid ) with and without 5 ppm F^- were used as soaking medium. The XRD and FTIR results showed that both the deposited fluoride-substituted hydroxyapatite ( F-HAp ) crystals in 1.5 SBF with F^- and hydroxyapatite ( HAp ) crystals in 1.5 SBF were carbonate-contain ing, mimicking human tooth enamel in chemical compositions. The SEM photos showed that needle-like F-HAp crystals had large aspect ratios and grew in bundles, which were similar to the crystals in human tooth enomel. The results provide available information on dental restoration.展开更多
The self-assembled metal halide perovskite(MHP)nanocrystal superlattices have attracted many researchers due to their exceptional optical and electrical properties.The bottom-up self-assembly can be facile to generate...The self-assembled metal halide perovskite(MHP)nanocrystal superlattices have attracted many researchers due to their exceptional optical and electrical properties.The bottom-up self-assembly can be facile to generate ideal and periodic structures.The superlattices’stability can be improved and the photoluminescence lifetime can be extended by an order of magnitude.However,due to lack of a comprehensive and systematic understanding of the internal interactions on self-assembled processes now,superlattices cannot be obtained controllably and play full use of their advantages.Therefore,gaining a deep insight of interaction forces about self-assemblies is the premise of designing and controlling the degree of self-assembly so as to prepare ideal materials.In this review,the definitions and functions of driving forces including van der Waals forces,electrostatic interactions and hydrogen bonds are discussed.Subsequently,we aim to explore the dominant factors affecting the driving forces,which can make a difference in the process of MHP self-assembly.Based on current researches,we emphasize on three aspects−the core of nanocrystals,surface ligands and solvents−to clarify their critical roles in controlling the driving forces.Finally,the outlooks and perspectives of how to facilitate the MHP self-assembly and their application on blue light emitting diodes are discussed.展开更多
We experimentally demonstrate that optical tweezers can be used to accelerate the self-assembly of colloidal particles at a water-air interface in this Letter. The thermal flow induced by optical tweezers dominates th...We experimentally demonstrate that optical tweezers can be used to accelerate the self-assembly of colloidal particles at a water-air interface in this Letter. The thermal flow induced by optical tweezers dominates the growth acceleration at the interface. Furthermore, optical tweezers are used to create a local growth peak at the growing front, which is used to study the preferential incorporation positions of incoming particles. The results show that the particles surfed with a strong Marangoni flow tend to fill the gap and smoothen the steep peaks. When the peak is smooth, the incoming particles incorporate the crystal homogeneously at the growing front.展开更多
In this study, self assembly behavior was induced for γ-alumina nanoparticles by adsorption of dimethyl disulfide. Following this trend, we have developed a chemical process to obtain 'y-alumina in the nano scale. S...In this study, self assembly behavior was induced for γ-alumina nanoparticles by adsorption of dimethyl disulfide. Following this trend, we have developed a chemical process to obtain 'y-alumina in the nano scale. Scanning electron microscopy images of the prepared γ-alumina showed big and strong agglomeration of the nanoparticles indicating that these nanoparticles have strong surface forces. Transmission electron microscopy images confirmed that the γ-alumina nanoparticles 3-7 nm in size were converted to uniform spherical shape in the size range of 1-2 mm after shaking with dimethyl disulfide in the presence of n-hexane at room temperature. This phenomenon did not appear in the case of alumina in the micro scale. The surface properties of the prepared γ-alumina in the nano scale were characterized and compared with the γ-alumina in the micro scale by using low temperature nitrogen adsorption-desorption system, indicating that the specific surface area of the prepared γ-alumina nanoparticles is larger than that of the γ-alumina in the micro scale. Furthermore, micro- and meso-pores were observed for the if-alumina nanoparticles while only mesoporous structure was detected for the γ-alumina in the micro scale. These experimental results suggested that the self assembly behavior of the γ-alumina nanoparticles may be due to the selective adsorption ofdimethyl disulfide in the micropores of these nanoparticles to act as bridge linking the nanoparticles.展开更多
基金Supported by the National Natural Science Foundation of China(Nos. 20476011 and 20371007).
文摘The self-assembly of clusters in inorganic systems is an interesting subject. The self-assembly of big molecules has been well established in biological systems. In addition, the coordination chemistry of metal-sulfur-nitrogen cluster complexes has been a very active and attracting field for many years as a result of the novelty and versatility of the crystal structures and reactivities of such clusters, as well as their potential applications as the models for the active sites in non-heme proteins. At the same time, there is currently considerable interest in the formation of metal complexes with heterocyclic ligands because of the diverse characteristics of ligands and their consequential wide range of applications.
基金Supported by National Natural Science Foundation(No.0 5 1730 0 3) Beijing Science and Technology New Star Program(No.H0 10 4 10 0 10 112 ) and Im portant Natural Science Foundation of Beijing(No.2 0 310 0 1) .
文摘The polymerization of amphiphilic self assemblies is a promising method to synthesize nano structured materials with novel properties. These materials have many attractive features for their application in biomedical area and materials science, such as catalysis, separation, surface modification, and therapeutics areas. A general review on the polymerization of lipids and surfactant self assemblies to amphiphilic self assemblies is given in this paper with 49 references. The polymerization and the subsequently resulted structure of lipids in different morphologies are summarized. The polymerization of polymerizable surfactants(surfmers) in emulsion and liquid crystalline phases are also discussed. The potential application of new nano porous materials is briefly described.
文摘The layer by layer complexation technique of polymer and metal ion was successfully utilized to fabricate the ultrathin multilayer film of poly(3 thiophene acetic acid (PTAA) and Tb 3+ ion by dipping the substrates alternatively in polymer and Tb 3+ ion aqueous solutions. UV-vis measurement revealed that the absorbance has linearity with the bilayer number from layer to layer and the X ray photoelectron spectrum (XPS) confirmed the existence of Tb 3+ ion. The pH of both the polymer and TbCl 3 solutions influence the thickness dramatically while the concentration of the solutions is not so sensitive. The luminescent spectrum of the complex film shows the characteristic emission of Tb 3+ ion as well as the ligand indicating the formation of the complex.
基金Supported by National Natural Science Foundation of China(No.0 5 1730 0 3) Beijing Science and Technology New StarProgram(No.H0 10 4 10 0 10 112 ) and Important Natural Science Foundation of Beijing(No.2 0 310 0 1) .
文摘Amphiphilic block copolymers can exhibit rich and complex morphologies in aqueous solutions, but these structures are usually delicate, easily disturbed by composition change or temperature change. In this work, the use of different methods to cross link block copolymer self assemblies in the presence of a selective solvent and to stabilize the structures is reviewed. In addition, the cross linking reaction kinetics of block copolymer amphiphilic self assemblies is briefly discussed.
基金Project supported by the National Natural Science Foundation of China (Grant No.50872147)the National High Technology Research and Development Program of China (Grant No.2007AA03Z305)the Special Doctoral Foundation of the Ministry of Education of China (Grant No.20775030)
文摘Gold nanorods with aspect ratios of from 1 (particles) to 31.6 were synthesized by the seed-mediated method and packed in a highly ordered structure on a large scale on silicon substrates through capillary force induced self-assembly behaviour during solvent evaporation. The gold nanorod surface exhibits a strong enhancing effect on Raman scattering spectroscopy. The enhancement of Raman scattering for two model molecules (2-naphthalenethiol and rhodamine 6C) is about 5-6 orders of magnitude. By changing the aspect ratio of the Au nanorods, we found that the enhancement factors decreased with the increase of aspect ratios. The observed Raman scattering enhancement is strong and should be ascribed to the surface plasmon coupling between closely packed nanorods, which may result in huge local electromagnetic field enhancements in those confined junctions.
文摘This study investigated the stability behaviour of molecular monolayer symmetric chemically modified tetraether lipids caldarchaeol-PO<sub>4</sub> on the amino-silanised silicon wafer using Langmuir-Blodgett films, Self Assembling Monolayers (SAMs), ellipsometry, and atomic force microscopy (AFM). The monolayers of caldarchaeol-PO<sub>4 </sub>were stable on the solid surface amino-silanised silicon wafer. The organizations of molecular monolayers caldarchaeol-PO<sub>4</sub> by Langmuir-Blodgett method and SAMs have been analyzed. The surface of pressure in Langmuir-Blodgett processing is carried out monolayers caldarchaeol-PO<sub>4</sub> more flat island inhomogeneous. Another method of monolayers caldarchaeol-PO<sub>4</sub> by SAMs is showed a large flat domain. Monolayers caldarchaeol-PO<sub>4</sub> by Langmuir-Blodgett method seems to be stable and chemically resistant after washing with organic solvent and an additional treatment ultrasonification with various thickness lipids arround 2 nm to 6 nm. Conversely, monolayer caldarchaeol-PO<sub>4</sub> by SAMs appears fewer than monolayers caldarchaeol-PO<sub>4</sub> by Langmuir-Blodgett method, the thickness of various from 1 nm to 3 nm.
基金supported by the Ningbo S&T Innovation 2025 Major Special Program (2018B10055)the K.C. Wong Magna Fund in Ningbo University, China。
文摘Inorganic NiO_(x) based inverted structure perovskite solar cells (PSCs) is reported to be more stable than that with the organic hole transport materials.In this work,NiO_(x)/MAPbI_(3) interface chemical reaction induced instability of perovskite is unveiled:Ni^(3+) and I^(-) exhibit redox reactions and deprotonation of MA^(+) happens,which result in interface defects and perovskite lattice deformation.Thus the defective interface accelerates the degradation of perovskite by defect pathways from the bottom interface to the perovskite surface contacting H_(2)O/O_(2).Self-assembled interlayer of NH_(2)^(-)end silane on NiO_(x)separates the reactive NiO_(x)and MAPbI_(3),tunes the interface energy states by–NH_(2) end group.As a result,the PSC based on the silane treated NiO_(x)achieves enhanced PCE of 20.1%with decent stability under environmental and extreme conditions (high temperature,high humidity,light infiltration).Our work highlights the interface chemical problem induced PSC instability and a simple interface modification to achieve the stable PSCs.
文摘The direct electron transfer of amino oxidase on electrode surface based on self assembly technique occurs at 505 mV( vs . Ag/AgCl), indicating that copper atoms are the electron transfer centers and catalytic centers of amino oxidase.
基金Project supported by the Polish Ministry of Science and Higher Education (NN204 0317 33)
文摘The self-assembled formation of a one-dimensional lanthanum salicylald imine coordination polymer was proved by the X-ray diffraction analysis of new l anthanum(Ⅲ) nitrate complex containing N,N’-bis(salicylidene)-1,5-pentanediami ne ligand(H2L) . It was obtained in situ in a one-step,metal-templated condensa tion of salicylaldehyde with 1,5-pentanediamine(cadaverine,biogenic polyamine) and characterized by microanalysis and spectroscopic(IR,ESI-MS,UV-Vis,and 1 H NMR) data. The [La(NO3) 3(μ-H2L) 2]∞ complex displayed 10-coordinate distorted bicapped dodecahedron geometry with unusual coordination pattern of undeprotonat ed salicylaldimines which acted as μ-bridging ditopic ligands using exclusivel y the oxygens as donor atoms with the nitrogen atoms not being involved in the c oordination environment.
基金This work was supported by the National Natural Science Foundation of China under Grant No.10744001.
文摘We demonstrate the self-assembly of solution-processible gold nanoparticles into the nanoholes consisting of patterned substrate through annealing, which facilitates successful fabrication of square lattices of gold nanocylinders with a period of 350 nm, a height of about 200 nm, and an aspect ratio larger than 2.
基金the National Natural Science Foundation of China(No.50702029)Shandong Provincial Education Department(No.J05D08)Natural Science Foundation of Qingdao(No.05-1-JC-89)
文摘Ordered zinc oxide (ZnO) rod arrays with very high orientation were fabricated on Si substrates by using a solution method. The substrate surfaces were functionalized by Self-Assembly Monolayers (SAMs). In the very early growth stage, the oriented ZnO crystals had already grown, which appeared to be the main reason why ZnO nanorods showed very high orientation. The un-dense and un-uniform SAMs provided a surface that was heterogeneous to ZnO nucleation. Consequently, highly oriented ZnO rods were selectively grown on the "coin-like" SAM-uncovered regions. The route developed here can provide some helpful information to control the nucleation and orientation of ZnO in aqueous solution. Also, the site-selective growth mechanisms can indicate a clue to grow patterned highly oriented ZnO nanorod arrays by the organic template.
基金Shanghai Municipal Science and Technology Major Project,Grant/Award Number:2018SHZDZX03Programme of Introducing Talents of Discipline to Universities,Grant/Award Number:B16017+2 种基金Shanghai Science and Technology Committee,Grant/Award Number:17520750100National Natural Science Foundation of China,Grant/Award Numbers:21672060,21790361,21871084,22025503Program of Shanghai Academic/Technology Research Leader,Grant/Award Number:19XD1421100。
文摘Developing high‐performance adhesive materials not only aims at industrial and social requirements but also bears the fundamental importance of understanding the chemical factors of biological adhesion to develop biomimetic adhesive materials.Owing to the wide development of supramolecular chemistry,numerous supramolecular tools are exploited and proved to be reliable in the replacement of traditional covalent materials by reversible noncovalent or dynamic covalent materials.Taking advantage of these readyto‐use supramolecular toolboxes,supramolecular adhesive materials are rising and promising toward“smart”adhesives,that is,enabling responsiveness,reversibility,and recyclability.Compared with polymeric adhesive materials,low‐molecular‐weight adhesives feature chemically precise structure,easier engineering by molecular design,and hence higher reproducibility.However,it remains highly challenging to make high‐performance adhesive materials by low‐molecular‐weight feedstocks.This review will focus on the recent advancement in the construction of supramolecular adhesive materials by smallmolecule self‐assembly.The design guidelines and consideration on the molecular scale will be discussed and summarized on how to enhance the strength of adhesives.Meanwhile,owing to the dynamic nature of supramolecular self‐assembly,several“smart”functions of such materials will be presented,such as stimuli–responsiveness and adaptiveness.Finally,current challenges and future perspectives of this emerging field will be proposed.
基金supported by Rachadapisek Sompote Fund for Postdoctoral Fellowship, Chulalongkorn University, Thailandthe Nanotechnology Center (NANOTEC), NSTDA Ministry of Science and Technology, Thailand, through its program of Center of Excellence Network+1 种基金National Research University Project of CHEthe Rachadapisek Sompote Endowment Fund (No. AM1041A)
文摘Polypropylene(PP) meltblown fibers were coated with titanium dioxide(Ti O2) nanoparticles using layer-by-layer(Lb L) deposition technique. The fibers were first modified with 3layers of poly(4-styrenesulfonic acid)(PSS) and poly(diallyl-dimethylammonium chloride)(PDADMAC) to improve the anchoring of the Ti O2 nanoparticle clusters. PDADMAC, which is positively charged, was then used as counter polyelectrolyte in tandem with anionic Ti O2 nanoparticles to construct Ti O2/PDADMAC bilayer in the Lb L fashion. The number of deposited Ti O2/PDADMAC layers was varied from 1 to 7 bilayer, and could be used to adjust Ti O2 loading. The Lb L technique showed higher Ti O2 loading efficiency than the impregnation approach. The modified fibers were tested for their photocatalytic activity against a model dye, Methylene Blue(MB). Results showed that the Ti O2 modified fibers exhibited excellent photocatalytic activity efficiency similar to that of Ti O2 powder dispersed in solution. The deposition of Ti O23 bilayer on the PP substrate was sufficient to produce nanocomposite fibers that could bleach the MB solution in less than 4 hr.Ti O2-Lb L constructions also preserved Ti O2 adhesion on substrate surface after 1 cycle of photocatalytic test. Successive photocatalytic test showed decline in MB reduction rate with loss of Ti O2 particles from the substrate outer surface. However, even in the third cycle, the Ti O2 modified fibers are still moderately effective as it could remove more than 95% of MB after 8 hr of treatment.
基金financially supported by the Project of Education Department of Liaoning Province,China(No.990790)the National Natural Science Foundation of China(No.51402035)
文摘Inspired by the curved branches of fractal trees, hooked Ni–Fe fibers were grown in situ in Ni–Fe composite coatings on a spheroidal graphite cast iron substrate. These hooked Ni–Fe fibers exhibited inclination angles of about 39°, which was in accordance with the theoretical prediction of 37°. Ni–Fe nanostructures self-assembled to form dendrites and evolved into hooked fibers by an oriented attachment reaction. The orientation rotation of Ni–Fe nanostructures played an important role in the growth of curved hooked Ni–Fe fibers. During sliding wear tests, the volume loss of the spheroidal graphite cast iron substrate was 2.2 times as large as that of the Ni–Fe coating reinforced by hooked fibers. The good load-transferring ability of hooked Ni–Fe fibers led to an improvement in their wear properties during wear tests.
基金the National High-tech Research and Development Program of China(''863''Program)(No.2012AA041402)National Natural Science Foundation of China(Nos.61175079and51105012)Fundamental Research Funds for the Central Universities (No.YWF-11-02-215)
文摘Swarm intelligence embodied by many species such as ants and bees has inspired scholars in swarm robotic researches. This paper presents a novel autonomous self-assembly distributed swarm flying robot-DSFR, which can drive on the ground, autonomously accomplish self-assembly and then fly in the air coordinately. Mechanical and electrical designs of a DSFR module, as well as the kinematics and dynamics analysis, are specifically investigated. Meanwhile, this paper brings forward a generalized adjacency matrix to describe configurations of DSFR structures. Also, the distributed flight control model is established for vertical taking-off and horizontal hovering, which can be applied to control of DSFR systems with arbitrary configurations. Finally, some experiments are carried out to testify and validate the DSFR design, the autonomous self-assembly strategy and the distributed flight control laws.
基金Financial support of the Research Grants Council of the Hong Kong Special Administration Region Earmarked Grant (CUHK4267/00P, CUHK 4209/99P, 2160122) and NNSFC 29974027 is gratefully acknowledged.
文摘It had very long been a dream in polymer science to synthesize long multi-block polymer chains with an orderedchain sequence and controllable block lengths. Using ionic or living free radical polymerization or furnishing each end ofpolymer blocks with a reactive functional group, one can only prepare heteropolymer chains with few long blocks, such asdiblock and triblock copolymers. The most plausible result so far was a pentablock copolymer. Recently, using a combinationof polymer physics and synthetic chemistry, we have invented self-assembly assisted polycondensation (SAAP). Thiscommunication reports the results of using this novel. method to connect 10-100 triblock polymer chains together to formlong multi-block heteropolymer chains with an ordered sequence and controllable block lengths.
文摘Chemical compositions and mierosturcture of mature human tooth enamel were investigated by XRD , FTIR and SEM to further understand the characteristics of tooth enamel. In order to obtain apatite crystals chemically and structurally similar to those in tooth enamel, biomimetic way was employed. Self-assembled monolyers terminated with-SO3 H groups were used as deposition substrates and 1.5 SBF ( the concentrations of Ca^2+ and PO4^3- ions 1.5 times ttum those in simulated body fluid ) with and without 5 ppm F^- were used as soaking medium. The XRD and FTIR results showed that both the deposited fluoride-substituted hydroxyapatite ( F-HAp ) crystals in 1.5 SBF with F^- and hydroxyapatite ( HAp ) crystals in 1.5 SBF were carbonate-contain ing, mimicking human tooth enamel in chemical compositions. The SEM photos showed that needle-like F-HAp crystals had large aspect ratios and grew in bundles, which were similar to the crystals in human tooth enomel. The results provide available information on dental restoration.
基金supported by the Foundation of Basic and Applied Basic Research of Guangdong Province(No.2019B1515120087)the Fellowship of China Postdoctoral Science Foundation(No.2021M690723)the Guangdong Basic and Applied Basic Research Foundation(No.2021A1515111222).
文摘The self-assembled metal halide perovskite(MHP)nanocrystal superlattices have attracted many researchers due to their exceptional optical and electrical properties.The bottom-up self-assembly can be facile to generate ideal and periodic structures.The superlattices’stability can be improved and the photoluminescence lifetime can be extended by an order of magnitude.However,due to lack of a comprehensive and systematic understanding of the internal interactions on self-assembled processes now,superlattices cannot be obtained controllably and play full use of their advantages.Therefore,gaining a deep insight of interaction forces about self-assemblies is the premise of designing and controlling the degree of self-assembly so as to prepare ideal materials.In this review,the definitions and functions of driving forces including van der Waals forces,electrostatic interactions and hydrogen bonds are discussed.Subsequently,we aim to explore the dominant factors affecting the driving forces,which can make a difference in the process of MHP self-assembly.Based on current researches,we emphasize on three aspects−the core of nanocrystals,surface ligands and solvents−to clarify their critical roles in controlling the driving forces.Finally,the outlooks and perspectives of how to facilitate the MHP self-assembly and their application on blue light emitting diodes are discussed.
基金supported by the National Natural Science Foundation of China under Grant Nos.11302220,61535011,and 11374292
文摘We experimentally demonstrate that optical tweezers can be used to accelerate the self-assembly of colloidal particles at a water-air interface in this Letter. The thermal flow induced by optical tweezers dominates the growth acceleration at the interface. Furthermore, optical tweezers are used to create a local growth peak at the growing front, which is used to study the preferential incorporation positions of incoming particles. The results show that the particles surfed with a strong Marangoni flow tend to fill the gap and smoothen the steep peaks. When the peak is smooth, the incoming particles incorporate the crystal homogeneously at the growing front.
基金supported through Annual Research Grants Program (ARP-29-111) by King Abdulaziz City for Scienceand Technology (KACST)
文摘In this study, self assembly behavior was induced for γ-alumina nanoparticles by adsorption of dimethyl disulfide. Following this trend, we have developed a chemical process to obtain 'y-alumina in the nano scale. Scanning electron microscopy images of the prepared γ-alumina showed big and strong agglomeration of the nanoparticles indicating that these nanoparticles have strong surface forces. Transmission electron microscopy images confirmed that the γ-alumina nanoparticles 3-7 nm in size were converted to uniform spherical shape in the size range of 1-2 mm after shaking with dimethyl disulfide in the presence of n-hexane at room temperature. This phenomenon did not appear in the case of alumina in the micro scale. The surface properties of the prepared γ-alumina in the nano scale were characterized and compared with the γ-alumina in the micro scale by using low temperature nitrogen adsorption-desorption system, indicating that the specific surface area of the prepared γ-alumina nanoparticles is larger than that of the γ-alumina in the micro scale. Furthermore, micro- and meso-pores were observed for the if-alumina nanoparticles while only mesoporous structure was detected for the γ-alumina in the micro scale. These experimental results suggested that the self assembly behavior of the γ-alumina nanoparticles may be due to the selective adsorption ofdimethyl disulfide in the micropores of these nanoparticles to act as bridge linking the nanoparticles.