Nanostructured columns with a length about several tens of micrometer and a diameter of about 80 nm were obtained by molecular recognition directed self-assembly of a pair of comple- mentary molecular components, 4-a...Nanostructured columns with a length about several tens of micrometer and a diameter of about 80 nm were obtained by molecular recognition directed self-assembly of a pair of comple- mentary molecular components, 4-amino-2 , 6-didodecylamino-1 , 3, 5-triazine(M) and 5- (4-dode- cyloxybenzylidene )-(1H, 3H)-2, 4, 6-pyrimidinetrione (B) in chloroform. In this system, with positive cooperativity, π-aromatic stacking and van der Waals interactions as well as hydrogen bonds cause the formation of the nanocolumns.展开更多
Thermally stable mesoporous silica and Ti-containing molecular sieves have been synthesized at mild temperature using low-cost and biodegradable --- amphoteric tetradecyl betaine as template. The physicochemical chara...Thermally stable mesoporous silica and Ti-containing molecular sieves have been synthesized at mild temperature using low-cost and biodegradable --- amphoteric tetradecyl betaine as template. The physicochemical characterizations proved that Ti(IV) could be incorporated in the mesoporous struture.展开更多
The hierarchical assemblies of precise nanoparticles(NPs)have created materials with emergent properties and functionalities.However,the complex assemblies remain unclear at a precise scale.Here,we show the hierarchic...The hierarchical assemblies of precise nanoparticles(NPs)have created materials with emergent properties and functionalities.However,the complex assemblies remain unclear at a precise scale.Here,we show the hierarchical self-assembly of atomically precise gold nanoclusters(Au NCs)with molecular rotor-based ligands(MRL),featuring a double-layer surface.Compared to two other types of monolayer-protected(MLP)Au NCs,the significantly reduced surface density for MRL Au NCs profoundly influences their assembly behavior within the lattice.Furthermore,the long length of rotor-based ligands and the rotational freedom of the phenyl-rings of rotor-based ligands also facilitate the assembly of NCs.Our works elucidate the hierarchical assembly on a precise scale,suggesting that the rotor-based ligand’s strategy offers promising potential for designing well-defined and more complex structures in supercrystals.展开更多
Molecular recognition directed self-assemblies from complementary molecular components, melamine and barbituric acid derivatives were studied by means of NMR, fluorescence, and TEM. It was found that both the process ...Molecular recognition directed self-assemblies from complementary molecular components, melamine and barbituric acid derivatives were studied by means of NMR, fluorescence, and TEM. It was found that both the process of the self-assembly and the morphologies of the result- ed self-assemblies could be mediated by modifying the structures of the molecular components used. The effect of the structures of the molecular components on the formation of the self-as- semblies was discussed in terms of intermolecular interactions.展开更多
Nanostructures self-assembled by cross-β peptides with ordered structures and advantageous mechanical properties have many potential applications in biomaterials and nanotechnologies. Quantifying the intra-and inter-...Nanostructures self-assembled by cross-β peptides with ordered structures and advantageous mechanical properties have many potential applications in biomaterials and nanotechnologies. Quantifying the intra-and inter-molecular driving forces for peptide self-assembly at the atomistic level is essential for understanding the formation mechanism and nanomechanics of various morphologies of self-assembled peptides. We investigate the thermodynamics of the intra-and inter-sheet structure formations in the self-assembly process of cross-β peptide KⅢIK by means of steered molecular dynamics simulation combined with umbrella sampling. It is found that the mechanical properties of the intra-and inter-sheet structures are highly anisotropic with their intermolecular bond stiffness at the temperature of 300 K being 5.58 N/m and 0.32 N/m, respectively. This mechanical anisotropy comes from the fact that the intra-sheet structure is stabilized by enthalpy but the inter-sheet structure is stabilized by entropy. Moreover, the formation process of KⅢIK intra-sheet structure is cooperatively driven by the van der Waals （VDW） interaction between the hydrophobic side chains and the electrostatic interaction between the hydrophilic backbones, but that of the inter-sheet structure is primarily driven by the VDW interaction between the hydrophobic side chains. Although only peptide KⅢIK is studied, the qualitative conclusions on the formation mechanism should also apply to other cross-β peptides.展开更多
The molecularly imprinted technology and the self-assembly technique were used together on the calixarene surface acoustic wave (SAW) chemical sensors to detect organophosphorus compounds. 25-(thioalkyl-alkoxy)-p-tert...The molecularly imprinted technology and the self-assembly technique were used together on the calixarene surface acoustic wave (SAW) chemical sensors to detect organophosphorus compounds. 25-(thioalkyl-alkoxy)-p-tertbutylcalix[4] arene with self-assembled monolayer character was the sensitive coating of the sensors. The sensors had a special response to organophosphorus compounds and the response frequency shift of this sensor to organophosphorus compounds in 0.1 mg/m3 was 350 Hz. The response frequency increased linearly with the increase of the concentration of DMMP in the range from 0.1 to 0.6 mg/m3. The possible explanation of the interaction between the coatings and organophosphorus compounds was discussed.展开更多
Stress and strain in the structure of self-assembled quantum dots constructed in the Ge/Si(001) system is calculated by using molecular dynamics simulation. Pyramidal hut cluster composed of Ge crystal with {105} face...Stress and strain in the structure of self-assembled quantum dots constructed in the Ge/Si(001) system is calculated by using molecular dynamics simulation. Pyramidal hut cluster composed of Ge crystal with {105} facets surfaces observed in the early growth stage are computationally modeled. We calculate atomic stress and strain in relaxed pyramidal structure. Atomic stress for triplet of atoms is approximately defined as an average value of pairwise (virial) quantity inside triplet, which is the product of vectors between each two atoms. Atomic strain by means of atomic strain measure (ASM) which is formulated on the Green’s definition of continuum strain. We find the stress (strain) relaxation in pyramidal structure and stress (strain) concentration in the edge of pyramidal structure. We discuss size dependency of stress and strain distribution in pyramidal structure. The relationship between hydrostatic stress and atomic volumetric strain is basically linear for all models, but for the surface of pyramidal structure and Ge-Si interface. This means that there is a reasonable correlation between atomic stress proposed in the present study and atomic strain measure, ASM.展开更多
Besides our previous experimental discovery （Zhao Y R, et al. 2015 Langmuir, 31, 12975） that acetonitrile （ACN） can tune the morphological features of nanostructures self-assembled by short peptides KIIIIK （KI4K...Besides our previous experimental discovery （Zhao Y R, et al. 2015 Langmuir, 31, 12975） that acetonitrile （ACN） can tune the morphological features of nanostructures self-assembled by short peptides KIIIIK （KI4K） in aqueous solution, further experiments reported in this work demonstrate that ACN can also tune the mass of the self-assembled nanostructures. To understand the microscopic mechanism how ACN molecules interfere peptide self-assembly process, we conducted a series of molecular dynamics simulations on a monomer, a cross-β sheet structure, and a proto-fibril of KI4K in pure water, pure ACN, and ACN-water mixtures, respectively. The simulation results indicate that ACN enhances the intra-sheet interaction dominated by the hydrogen bonding （H-bonding） interactions between peptide backbones, but weakens the inter-sheet interaction dominated by the interactions between hydrophobic side chains. Through analyzing the correlations between different groups of solvent and peptides and the solvent behaviors around the proto-fibril, we have found that both the polar and nonpolar groups of ACN play significant roles in causing the opposite effects on intermolecular interactions among peptides. The weaker correlation of the polar group of ACN than water molecule with the peptide backbone enhances H-bonding interactions between peptides in the proto-fibril. The stronger correlation of the nonpolar group of ACN than water molecule with the peptide side chain leads to the accumulation of ACN molecules around the proto-fibril with their hydrophilic groups exposed to water, which in turn allows more water molecules close to the proto-fibril surface and weakens the inter-sheet interactions. The two opposite effects caused by ACN form a microscopic mechanism clearly explaining our experimental observations.展开更多
The effect of buried misfit dislocation on the distribution of Ge self-assembled quantum dots (SAQDs) grown on a relaxed SiGe buffer layer was investigated. The strain field of arrays of buried dislocations in a relax...The effect of buried misfit dislocation on the distribution of Ge self-assembled quantum dots (SAQDs) grown on a relaxed SiGe buffer layer was investigated. The strain field of arrays of buried dislocations in a relaxed SiGe buffer layer provided preferential nucleation sites for quantum dots. Burgers vector analysis using plan-view transmission electron microscopy (TEM) verified that the preferential nucleation sites of Ge SAQDs depended on the Burgers vector direction of corresponding dislocations. The measurement of the lateral distance between SAQDs and dislocations together with crosssection TEM observation clarified that the location of SAQDs was at the intersection of the dislocation slip plane and the top surface. The misfit strain should be an additional factor governing the uniformity in size, shape and distribution of Ge SAQDs.展开更多
In this letter. we report that oxidation of 4-aminothiophenol self-assembled monolayeron An electrode produces a couple of redox current peaks with close peak potentials in 0.5 mol/LHCIO4 aqueous solution, and the pea...In this letter. we report that oxidation of 4-aminothiophenol self-assembled monolayeron An electrode produces a couple of redox current peaks with close peak potentials in 0.5 mol/LHCIO4 aqueous solution, and the peaks are ascribed to an electroactive monolayer.Electrochemical properties of the monolayer polymer were investigated with use ofelectrochemical quartz crystal microbalance and cyclic voltammetry.展开更多
基金the National Natural Science Foundation of China.
文摘Nanostructured columns with a length about several tens of micrometer and a diameter of about 80 nm were obtained by molecular recognition directed self-assembly of a pair of comple- mentary molecular components, 4-amino-2 , 6-didodecylamino-1 , 3, 5-triazine(M) and 5- (4-dode- cyloxybenzylidene )-(1H, 3H)-2, 4, 6-pyrimidinetrione (B) in chloroform. In this system, with positive cooperativity, π-aromatic stacking and van der Waals interactions as well as hydrogen bonds cause the formation of the nanocolumns.
文摘Thermally stable mesoporous silica and Ti-containing molecular sieves have been synthesized at mild temperature using low-cost and biodegradable --- amphoteric tetradecyl betaine as template. The physicochemical characterizations proved that Ti(IV) could be incorporated in the mesoporous struture.
基金supported by the National Key R&D Program of China(No.2023YFC3404200)the National Natural Science Foundation of China(Nos.21974147,22325406)+1 种基金the 2022 Shanghai“Science and Technology Innovation Action Plan”Fundamental Research Project,China(No.22JC1401203)the Science Foundation of the Shanghai Municipal Science and Technology Commission,China(No.21dz2210100).
文摘The hierarchical assemblies of precise nanoparticles(NPs)have created materials with emergent properties and functionalities.However,the complex assemblies remain unclear at a precise scale.Here,we show the hierarchical self-assembly of atomically precise gold nanoclusters(Au NCs)with molecular rotor-based ligands(MRL),featuring a double-layer surface.Compared to two other types of monolayer-protected(MLP)Au NCs,the significantly reduced surface density for MRL Au NCs profoundly influences their assembly behavior within the lattice.Furthermore,the long length of rotor-based ligands and the rotational freedom of the phenyl-rings of rotor-based ligands also facilitate the assembly of NCs.Our works elucidate the hierarchical assembly on a precise scale,suggesting that the rotor-based ligand’s strategy offers promising potential for designing well-defined and more complex structures in supercrystals.
基金the National Natural Science Foundation of China.
文摘Molecular recognition directed self-assemblies from complementary molecular components, melamine and barbituric acid derivatives were studied by means of NMR, fluorescence, and TEM. It was found that both the process of the self-assembly and the morphologies of the result- ed self-assemblies could be mediated by modifying the structures of the molecular components used. The effect of the structures of the molecular components on the formation of the self-as- semblies was discussed in terms of intermolecular interactions.
基金Project supported by the National Basic Research Program of China(Grant No.2013CB932804)the National Natural Science Foundation of China(Grant Nos.11421063,11647601,11504431,and 21503275)+1 种基金the Scientific Research Foundation of China University of Petroleum(East China)for Young Scholar(Grant Y1304073)financial support through the CAS Biophysics Interdisciplinary Innovation Team Project(Grant No.2060299)
文摘Nanostructures self-assembled by cross-β peptides with ordered structures and advantageous mechanical properties have many potential applications in biomaterials and nanotechnologies. Quantifying the intra-and inter-molecular driving forces for peptide self-assembly at the atomistic level is essential for understanding the formation mechanism and nanomechanics of various morphologies of self-assembled peptides. We investigate the thermodynamics of the intra-and inter-sheet structure formations in the self-assembly process of cross-β peptide KⅢIK by means of steered molecular dynamics simulation combined with umbrella sampling. It is found that the mechanical properties of the intra-and inter-sheet structures are highly anisotropic with their intermolecular bond stiffness at the temperature of 300 K being 5.58 N/m and 0.32 N/m, respectively. This mechanical anisotropy comes from the fact that the intra-sheet structure is stabilized by enthalpy but the inter-sheet structure is stabilized by entropy. Moreover, the formation process of KⅢIK intra-sheet structure is cooperatively driven by the van der Waals （VDW） interaction between the hydrophobic side chains and the electrostatic interaction between the hydrophilic backbones, but that of the inter-sheet structure is primarily driven by the VDW interaction between the hydrophobic side chains. Although only peptide KⅢIK is studied, the qualitative conclusions on the formation mechanism should also apply to other cross-β peptides.
文摘The molecularly imprinted technology and the self-assembly technique were used together on the calixarene surface acoustic wave (SAW) chemical sensors to detect organophosphorus compounds. 25-(thioalkyl-alkoxy)-p-tertbutylcalix[4] arene with self-assembled monolayer character was the sensitive coating of the sensors. The sensors had a special response to organophosphorus compounds and the response frequency shift of this sensor to organophosphorus compounds in 0.1 mg/m3 was 350 Hz. The response frequency increased linearly with the increase of the concentration of DMMP in the range from 0.1 to 0.6 mg/m3. The possible explanation of the interaction between the coatings and organophosphorus compounds was discussed.
文摘Stress and strain in the structure of self-assembled quantum dots constructed in the Ge/Si(001) system is calculated by using molecular dynamics simulation. Pyramidal hut cluster composed of Ge crystal with {105} facets surfaces observed in the early growth stage are computationally modeled. We calculate atomic stress and strain in relaxed pyramidal structure. Atomic stress for triplet of atoms is approximately defined as an average value of pairwise (virial) quantity inside triplet, which is the product of vectors between each two atoms. Atomic strain by means of atomic strain measure (ASM) which is formulated on the Green’s definition of continuum strain. We find the stress (strain) relaxation in pyramidal structure and stress (strain) concentration in the edge of pyramidal structure. We discuss size dependency of stress and strain distribution in pyramidal structure. The relationship between hydrostatic stress and atomic volumetric strain is basically linear for all models, but for the surface of pyramidal structure and Ge-Si interface. This means that there is a reasonable correlation between atomic stress proposed in the present study and atomic strain measure, ASM.
基金Project supported by the National Basic Research Program of China(Grant No.2013CB932804)the National Natural Science Foundation of China(Grant Nos.91227115,11421063,11504431,and 21503275)+1 种基金the Fundamental Research Funds for Central Universities of China(Grant No.15CX02025A)the Application Research Foundation for Post-doctoral Scientists of Qingdao City,China(Grant No.T1404096)
文摘Besides our previous experimental discovery （Zhao Y R, et al. 2015 Langmuir, 31, 12975） that acetonitrile （ACN） can tune the morphological features of nanostructures self-assembled by short peptides KIIIIK （KI4K） in aqueous solution, further experiments reported in this work demonstrate that ACN can also tune the mass of the self-assembled nanostructures. To understand the microscopic mechanism how ACN molecules interfere peptide self-assembly process, we conducted a series of molecular dynamics simulations on a monomer, a cross-β sheet structure, and a proto-fibril of KI4K in pure water, pure ACN, and ACN-water mixtures, respectively. The simulation results indicate that ACN enhances the intra-sheet interaction dominated by the hydrogen bonding （H-bonding） interactions between peptide backbones, but weakens the inter-sheet interaction dominated by the interactions between hydrophobic side chains. Through analyzing the correlations between different groups of solvent and peptides and the solvent behaviors around the proto-fibril, we have found that both the polar and nonpolar groups of ACN play significant roles in causing the opposite effects on intermolecular interactions among peptides. The weaker correlation of the polar group of ACN than water molecule with the peptide backbone enhances H-bonding interactions between peptides in the proto-fibril. The stronger correlation of the nonpolar group of ACN than water molecule with the peptide side chain leads to the accumulation of ACN molecules around the proto-fibril with their hydrophilic groups exposed to water, which in turn allows more water molecules close to the proto-fibril surface and weakens the inter-sheet interactions. The two opposite effects caused by ACN form a microscopic mechanism clearly explaining our experimental observations.
文摘The effect of buried misfit dislocation on the distribution of Ge self-assembled quantum dots (SAQDs) grown on a relaxed SiGe buffer layer was investigated. The strain field of arrays of buried dislocations in a relaxed SiGe buffer layer provided preferential nucleation sites for quantum dots. Burgers vector analysis using plan-view transmission electron microscopy (TEM) verified that the preferential nucleation sites of Ge SAQDs depended on the Burgers vector direction of corresponding dislocations. The measurement of the lateral distance between SAQDs and dislocations together with crosssection TEM observation clarified that the location of SAQDs was at the intersection of the dislocation slip plane and the top surface. The misfit strain should be an additional factor governing the uniformity in size, shape and distribution of Ge SAQDs.
文摘In this letter. we report that oxidation of 4-aminothiophenol self-assembled monolayeron An electrode produces a couple of redox current peaks with close peak potentials in 0.5 mol/LHCIO4 aqueous solution, and the peaks are ascribed to an electroactive monolayer.Electrochemical properties of the monolayer polymer were investigated with use ofelectrochemical quartz crystal microbalance and cyclic voltammetry.
