Variation of Surface Adhesion Force During the Formation of OTS Self-assembled Monolayer Investigated by AFM

Variation of the surface adhesion force during the formation of octadecyl trichlorosilane (OTS) self-assembled monolayer on a glass substrate surface was investigated by atomic force microscope (AFM). The research shows that the hydrophobicity and the adhesion force of the sample surface increases gradually while the substrate surface is covered by OTS molecules as the reaction proceeds. After 15min reaction, a close-packed and smooth OTS self-assembled monolayer could form on the glass substrate surface with an advancing contact angle of 105° and an interfacial energy of 55.79mJ·m-2.

Synthesis of a New Porphyrin-fluorescein Hybrid and its Supramolecular Self-assembly with Amino-porphyrinatomanganese(Ⅲ) by Hydrogen-bonding

A new porphyrin-fluorescein hybrid 2 (Fl-PPTPP) has been synthesized and characterized by UV-Vis, IR, H-NMR, ESI-MS and elemental analysis. The supramolecular 1 self-assembly of Fl-PPTPP with amino-porphyrinatomanganese [Mn (p-APTPP)Cl] by hydrogen-bonding was studied using fluorescence spectroscopic titration and ESI-MS.

Design and Synthesis of a Highly Stable Six-hydrogen-bonded Serfassembly Yellowish Green Electroluminescent Molecular Duplex

This paper describes the design, synthesis and characterization of a hydrogen-bonded molecular duplex with 1,8-naphthalimide fluorescent pendants. The two oligoamide molecular strands, with complementary hydrogen bond sequences of DDADAA and AADADD, can form an ultra stable self-assembly duplex. Its molecular structure was confu-med by ^1H NMR and ESI-MS, and its photoluminescence properties were determined. The resulting duplex exhibited a dramatically enhanced photoluminescence （PL） quantum efficiency of 63.7% compared to the corresponding 1,8-naphthalimide segment （32.4%）, suggesting that the formation of the duplex with larger molecular weight could successfully inhibit the quenching of the fluorescent pendant. This novel duplex is a prospective candidate for new electroluminescent emitter.

In situ AFM investigation of dual-mode self-assembling peptide

Nanostructures/patterns formed by biomolecules can produce different physicochemical properties in terms of hydrophobicity, zeta-potential, color, etc., which play paramount roles in life. Peptides, as the main bio-building blocks, can form nanostructures with different functions,either in solutions or on interfaces. Previously, we synthesized a short peptide with the inspiration of an Alzheimer’s disease-related peptide: amyloid β peptide(A-p),namely GAV-9, which can epitaxially self-assemble into regular nanofilaments on liquid-solid interfaces, and it was found that both the hydrophobicity and charge state of the interfaces can significantly influence its assembling behavior. It was also reported that another A-β-containing dipeptide, FF,can self-assemble into nanostructures in solutions. Owing to the close relationship between these two short peptides, it is interesting to conjugate them into a de novo peptide with two separated structural domains and study its self-assembling behavior. To this end, herein we have synthesized the GAV-FF peptide with a sequence of NH2-VGGAVVAGVFF-CONH2 and verified its selfassembling property using the in situ liquid-phase atomic force microscopy. The results show that the GAV-FF peptide can self-assemble into nanofilaments both in solutions and on aqueous-solid interfaces, but with different morphologies. The FF domain accelerates the template-assisted self-assembling(TASA) process of the GAV domain, which in return enhances the solubility of FF in aqueous solutions and further participates in the fibrillization of FF. The current results could help deepen the understanding of the aggregation mechanism of diseaserelated peptides and could also shed light on the strategies to create artificial bio-functional nanostructures/patterns,which hold a significant potential for biomedical applications.

Various Silver Nanostructures on Sapphire Using Plasmon Self-Assembly and Dewetting of Thin Films

Silver(Ag) nanostructures demonstrate outstanding optical, electrical, magnetic, and catalytic properties and are utilized in photonic, energy, sensors, and biomedical devices.The target application and the performance can be inherently tuned by control of configuration, shape, and size of Ag nanostructures. In this work, we demonstrate the systematical fabrication of various configurations of Ag nanostructures on sapphire(0001) by controlling the Ag deposition thickness at different annealing environments in a plasma ion coater. In particular, the evolution of Ag particles(between 2 and 20 nm),irregular nanoclusters(between 30 and 60 nm), and nanocluster networks(between 80 and 200 nm) are found be depended on the thickness of Ag thin film. The results were systematically analyzed and explained based on the solid-state dewetting,surface diffusion, Volmer–Weber growth model, coalescence,and surface energy minimization mechanism. The growth behavior of Ag nanostructures is remarkably differentiated at higher annealing temperature(750 ℃) due to the sublimation and temperature-dependent characteristic of dewetting process.In addition, Raman and reflectance spectra analyses reveal that optical properties of Ag nanostructures depend on their morphology.

Hexacyanoferrate as the Electrochemical Probe for 2-Mercaptobenzothiazole Modified Gold Electrode

A gold electrode covered with selfassembled monolayers of 2mercaptobenzothiazole(Au/MBT)has been developed and its electrochemical characteristics have been investigated in detail.Using hexacyanoferrate as the electrochemical probe for studying the characteristics of the MBT monolayer film,the results,obtained by A.C.impedance spectroscopy technique,show that the electron transfer of hexacyanoferrate()on Au|MBT in higher pH media was more difficult than that obtained in H2SO4 medium or on a bare gold electrode.The electrochemical reversibility of Fe(CN)3-6/Fe(CN)4-6 changed with pH of the solution due to the proton and deproton states of N atom of MBT.The relationship between the coverage of MBT on Au surface or pH and the apparent heterogeneous rate constant was derived and discussed.The double layer capacitance of Au|MBT is(76455)F/cm2.The characteristic frequency was dependent on the pH of the solution.

The 2017 IRDS Lithography Roadmap

Technology roadmaps have been a part of the semiconductor industry for many years.The first roadmap was Moore’s law,which started as an empirical observation that competitive forces then turned into a prediction that became an industry roadmap.Then the ITRS roadmap was developed and for many years was used by leading edge semiconductor producers to drive new technology they needed.Now there is the IRDS roadmap,which projects semiconductor end user requirements and develops a technology roadmap based on those requirements.The 2017 IRDS roadmap was just released.To prepare the roadmap,we received input from experts around the world.The roadmap predicts that the requirements of high performance logic will drive the development of different device structures in logic chips.Memory technology will also advance but is more focused on cost than high performance logic is.Because of this,there may be a split in the patterning roadmaps for different types of devices.Logic will adopt EUV and its extensions,while flash memory will consider nanoimprint.Directed self-assembly and direct write e-beam are also being developed.DSA has the potential to improve CD uniformity and lower costs.Direct write e-beam promises to make personalization of chips more feasible.DRAM memory will trail logic in critical dimensions and will adopt EUV when it becomes cost effective.The lithography community will both have to make EUV work and overcome the challenges of randomness in CDs and resist performance,while memory will try to make nanoimprint a reliable and low defect method of patterning.Long term,logic is expected to start focusing on 3D architectures in the late 2020’s.This will put a tremendous stress on the yield of patterning processes and on reducing the number of process steps that are required.It will also put more focus on hole type patterns,which will become one of the key patterning challenges in the future.

Ce6 nanoassemblies:Molecular mechanism and strategies for combinational anticancer therapy Special Collection:Aggregation-Induced Processes and Functions

Nowadays,cancer has become the leading cause of death worldwide,driving the need for effective therapeutics to improve patient prognosis.Photodynamic therapy(PDT)has been widely applied as an antitumor modality,owing to its minimal invasiveness,localized tumor damage,and high safety profile.However,its efficacy is limited by poor stability of photosensitizers,inadequate tumor accumulation,and a complex tumor microenvironment.To overcome these challenges,extensive endeavors have been made to explore the co-assembly of the widely used photosensitizer chlorin e6(Ce6)with various functional small molecules to enhance pharmacodynamic activity.This review provides a comprehensive overview of current studies on Ce6-based nanoparticles for effective PDT and precise delivery of functional molecules.The self-assembly mechanism will be discussed in detail,with a focus on potential strategies for combinational therapy with PDT.

Hydrogels totally from inorganic nanosheets and water with mechanical robustness,self-healing,controlled lubrication and anticorrosion

Synthetic hydrogels with attractive mechanical strength and self-healing are particular appealing,in light of their significance and prospects in industrial,engineering and biomimetic fields.Fabricating various mechanically robust and self-healable hydrogels have achieved some successes in using strong covalently bonded organic polymers as building blocks.However,creation of such soft materials entirely building on rigid inorganic components remains greatly challenging,because inorganic materials are usually poorly flexible and processable.In this study,mechanical robustness and self-recovery are successfully integrated into a single-component colloidal hydrogel system of aluminium hydroxide nanosheets(AHNSs).The inorganic colloidal hydrogel gains an excellent elasticity and stiffness,as indicated by its elastic modulus>10 MPa,due to the use of tough AHNS gelator and the formation of long-range ordered lamellar architectures consisting of self-assembled side-to-side or interlaced-stacking NS superstructures.The metastability in internal gel network endows the hydrogel a self-healing efficiency of larger than 100%.The AHNS hydrogel has been demonstrated to be effectively lubricative and anti-corrosive.Its mechanical,tribological and anticorrosion properties can be optimized by tuning its internal NS configuration and salt content.Our study may be a potent replenishment to the scope of materials science and may provide new insights into nanotechnology,colloidal chemistry,green tribology and mechanical engineering.

2,5-Dialkoxylphenyl-l,3,4-oxadiazoles as efficient organogelators and their self-assembling property

Four 2,5-dialkoxylphenyl-l,3,4-oxadiazoles are shown to be efficient organogelators. These com- pounds readily form stable gels in many organic solvents and their gelation property as well as supramolecular structures were investigated by scanning electron microscopy （SEM）, X-ray diffraction （XRD）, 1H nuclear magnetic resonance （1H NMR）, and ultraviolet-visible spectroscopy （UV-vis）. The results indicate that the gelator molecules self-assemble into gels with elongated fibrous networks and layer structures, and van der Waals interaction is the main driving force.

A Robust Strategy for Precise Fabrication of Rigid-Flexible Coupling Dendrimers toward Self-Coordinated Hierarchical Assembly

Advances in nanotechnology depend upon expanding the ability to create biologically inspired complex materials with well-defined multidimensional structures.Fabrication of hybrid hierarchical structures by combining colloidal organic and inorganic building blocks remains a challenge due to the difficulty in preparing a diverse spectrum of rigid-flexible coupling units of precise shape and size.Herewe reportageneral strategy for crafting amyriad of uniform aggregates via manipulating self-assembly of distinct dendimers with precisely controlled polyhed raloligomeric silse squioxane(POSS)-embedded cores integrating stiffness and ductility.The rigidity of POSS units exerts steric effects onself-amplification of hydrophobic do mains while the flexibility from internally ductile linkages provides ideal scenarios in establishing self-adaptive structural optimization,which subsequently drive the assemblies to proceed into hierarchical self-assembly via multiple coordination effects,generating highly complex multi compartment micelles(MCMs)without any preprocessing.Our facile approach enables a robust modular nanofabrication of well-organized dendrimers toward artificial functional systems with defined geometric architectures and intriguing functions for advanced biological applications.

Multidimensional Mass Spectrometry Assisted Metallo-Supramolecular Chemistry

Metallo-supramolecular chemistry based on the reversible,directional,and predictable noncovalent interaction of metal–ligand coordination has been widely applied in constructing a myriad of two-and threedimensional supramolecules with sophisticated structures.The development of metallo-supramolecular chemistry highly relies on facile characterization methods.For advancement of structural complexity with desired functions,however,conventional crystallographicandspectroscopiccharacterizationsarelimited by crystal growth,sample purity,and severe signal overlaps.With high sensitivity and low requirement for purity,multidimensional mass spectrometry(MS),including electrospray ionization-MS(ESI-MS),tandem MS(MS2),and ion mobility-MS(IM-MS),is emerging as an essential analytical tool for characterization of the chemical compositions,connectivity,stability,shape,and size of metallo-supramolecules,as well as kinetic and thermodynamic features of self-assembly processes.Thus,this review mainly focuses on the recentdevelopment ofmultidimensionalMSinmetallosupramolecular characterization and discusses how ESI-MS,MS2,and IM-MS assist the development of metallo-supramolecular chemistry.

AIE-based drug/gene delivery system:Evolution from fluorescence monitoring alone to augmented therapeutics

The aggregation-induced emission luminogens(AIEgens)with unique photophysical properties propel the rapid development of novel delivery systems for drugs and genes.In this review,we first presented numeral classic types of delivery systems based on light-up AIEgens for real-time monitoring of the delivery processes and evaluation of therapeutic outcomes of delivered drugs or genes.Next,general strategies were discussed for the delicately structural design of AIEgens that can self-assemble into bright therapeutic carriers through covalent or noncovalent interactions.Furthermore,given the unprecedented enhancements in therapeutic effects through the use of multimodes of therapy,AIEgens that were endowed with multiproperties and functionalities were investigated in the constructions of delivery systems for multimodality therapy.Especially,the combinational uses of AIE photosensitizers with chemo drug and small interference RNA(siRNA)were given as examples of augmenting the therapeutic performance in drug-resistant treatment and moderate immunotherapy by showing synergistic effects.

Cluster-assembled materials:Ordered structures with advanced properties

Cluster-assembled materials(CAMs)present delicate structures and tailored properties,which have gained extensive interest in recent years.Due to the noncovalent linkage and size of sub-1 nm,clusters present polymer-like solution behaviors distinct from conventional nanocrystals,whereby a variety of CAMs with different constructions have been fabricated.To our knowledge,the morphologies and properties of CAMs are closely connected,which are strongly dependent on the structure and coordination state of cluster building blocks.For the CAMs with superior performances,the specific arrangement and surroundings of clusters at subnanometer scale usually result in wellorganized structures.In this review,we will summarize the recent progress of CAMs with highly ordered structures and advanced properties,where polyoxometalate cluster assemblies as well as cluster-nuclei co-assemblies are involved.The application potentials of CAMs are then discussed,especially on the cluster arrangements and interactions at subnanometer scale.However,current researches are far from reaching the point,and future efforts are needed before the nature of cluster-based nanostructures can be sufficiently revealed.We hope this article can offer unique insights and instructive understanding to the CAMs.

Anion-Coordination-Driven Assembly of Anionic Hexagonal and Square Architectures and the Structural Interconversion

A biphenyl-bridged bis-tris(urea)ligand L was rationally designed with a favorable angle to construct a hexagon-shaped A_(6)L_(6)(A=anion)complex upon assembly with phosphate anions(PO_(4)^(3−))via anioncoordination-driven assembly(ACDA).Due to the moderate flexibility of L,another well-defined discrete architecture,a square-like A_(4)L_(4) complex,has also been obtained from ligand L and PO_(4)^(3−).Interconversion between these two self-assemblies can be readily realized by solvent regulation.In addition,the two anionic architectures display different binding abilities for selected cationic guest molecules,enabling the uptake of a desired guest from amixture of guests.