Controlled Directional Water‐Droplet Spreading on a High‐Adhesion Surface

Controlled directional spreading of a droplet on a smart high‐adhesion surface was made possible by simply controlling anodic oxidation. The wettability gradient of the surface was controlled from 0.14 to 3.38° mm^?1 by adjusting the anodic oxidation conditions. When a water droplet made contact with the substrate, the droplet immediately spread in the direction of the wettability gradient but did not move in other directions, such as those perpendicular to the gradient direction, even when the surface was turned upside down. The spreading behavior was mainly controlled by the wettability gradient. Surfaces with a V‐ or inverse‐V‐shaped wettability gradient were also formed by the same method, and two droplets on these surfaces spread either toward or away from one another as designed. This method could be used to oxidize many conductive substrates (e.g., copper, aluminum) to form surfaces with variously shaped wettability gradients. It has potential for application in microfluidic devices.     

Droplet Precise Self‐Splitting on Patterned Adhesive Surfaces for Simultaneous Multidetection

Precise separation and localization of microdroplets are fundamental for various fields, such as high‐throughput screening, combinatorial chemistry, and the recognition of complex analytes. We have developed a droplet self‐splitting strategy to divide an impacting droplet into predictable microdroplets and deposit them at preset spots for simultaneous multidetection. No matter exchange was observed between these microdroplets, so they could be manipulated independently. Droplet self‐splitting was attributed to anisotropic liquid recoiling on the patterned adhesive surface, as influenced by the droplet Weber number and the width of the low‐adhesive stripe. A quantitative criterion was also developed to judge the droplet self‐splitting capability. The precise separation and distribution of microdroplets enabled simultaneous arrayed reactions and multiple analyte detection using one droplet of sample.     

Self‐Consistent Field Modeling of Three‐Dimensional Morphologies of Branched Lipid Surfactant at Air‐Water Interface

Three‐dimensional mesoscopic morphologies and the thermodynamics of structural phase transitions of amphiphilic lipids at air‐water interfaces are studied using self‐consistent field theory. Changing the relative amount of lipids in the system led to a series of 3D morphologic phases with varying average interfacial area per molecule, mimicking a compression of the model membranes. Membranes of both saturated and unsaturated lipids undergo a transition from cylindrical micelle to lamella when the lipid content in the system increases from 2% to about 19–20%. With further increase in the lipid content, saturated lipids first develop non‐uniform quasi‐2D distributions in the lamella and then gradually transform into a hybrid morphology containing quasi‐planar lamellae. In contrast, unsaturated lipids develop reverse‐micellar morphologies.

     

仿生表面液固界面摩擦力的动态调控

仿生超疏水材料在自清洁、防雾抗冰、油水分离、集水等领域有着重要应用;而在不同疏水状态之间的转换将大大促进仿生超疏水材料在智能技术领域的应用.利用软印刷技术将玫瑰花表面微观结构转印到聚氨酯弹性体PU膜表面,利用机械应力实现表面微结构的动态实时调控,实现了表面微观结构在各向同性与各向异性之间的可逆转换;利用毛细管投影传感技...     

Continuous Bulk Process for the Production of High‐Impact Polystyrene: Recent Developments in Modeling and Control

This work presents (in a wider perspective), some of our recent developments in the mathematical modeling and control of bulk polymerization for the production of HIPS. The recent model by Casís assumes the polymerization to be heterogeneous, and it calculates (in two phases) the global molecular structure of the three polymeric components of HIPS (free polystyrene, unreacted polybutadiene, and graft copolymer). At present, a model is being developed capable of estimating the average particle morphology (salami or core‐shell). Assuming a continuous bulk HIPS process as homogeneous, Luciani estimated the evolution of the MFI of the final product during changes of grade, with the aim of minimizing the intermediate off‐spec product. Finally, an unpublished simulation is presented that describes the transitions between the steady state of a HIPS‐grade and that of a general‐purpose polystyrene.

     

Kinetic Modeling of Semi‐Interpenetrating Polymer Network (SIPN) Process ‐ A Comprehensive Study on the Case of Polyethylene/Polystyrene Semi‐I IPN

A comprehensive kinetic model is developed for a semi‐interpenetrating polymer network (SIPN) process, which involves simultaneous crosslinking, grafting, and degradation. Computational expense has been reduced considerably through a new component decomposition strategy, where a continuous variable approximation and a fixed pivot technique are applied for modeling each component. The inter‐polymer formulation is then reconstructed by a statistical approach. Based on the kinetic parameters obtained from the literature and a series of experiments, the model provides consistent agreement for gel fraction, joint molecular weight distribution (MWD) and polymer composition predicted in the studied cases, showing promising capability for the SIPN industrial application as well as for other polymer composite systems.

     

Modeling of Nitroxide‐Mediated Semibatch Radical Polymerization

A mechanistic model is developed for high‐temperature (138 °C) styrene semibatch thermally and conventionally initiated FRP, as well as NMP with a two‐component initiating system (tert‐butyl peroxyacetate, 4‐hydroxy‐TEMPO). The model, using kinetic coefficients from literature, provides a good representation of the FRP experimental results. Implementation of a gel effect correlation to represent the change in the diffusion‐controlled termination rate coefficient with conversion improves the fit to the thermally initiated system, but is not required to represent the production of low molecular weight material ( Dalton) by conventionally initiated FRP or NMP. The low initiator efficiency found in NMP is well explained by a reaction network involving combination of free nitroxide with methyl radicals formed from initiator decomposition.

     

Room‐Temperature Synthesis of Covalent Organic Frameworks with a Boronic Ester Linkage at the Liquid/Solid Interface

With various prospected applications in the field of nanoelectronics and catalysis, on‐surface synthesis of single‐layer covalent organic frameworks (surface COFs) with designable structures and properties have attracted enormous interest. Herein, we report on a scanning tunneling microscopic investigation of the surface‐confined synthesis of a covalently bonded boronic ester network directly at the octanoic acid/ highly oriented pyrolytic graphite(HOPG) interface under room temperature. The dynamic reaction process was investigated in detail. STM results indicate that the surface networks undergo structural evolution from a hybrid covalent/noncovalent multiwall porous network to single‐wall hexagonal COF with the decrease of monomer concentration. Further experimental observation disclosed that the boronic ester‐linked system is sensitive to instantaneous voltage pulses and the stimulation of the STM tip. In addition, the ¹H NMR spectra has further confirmed that the surface and octanoic acid may play important roles in promoting the reaction between 4,4′‐phenylazobenzoyl diboronic acid (ABBA) and 2,3,6,7,10,11‐hexahydroxytriphenylene (HHTP) building units.     

Interface characterization of a metal‐oxide‐semiconductor structure by biased X‐ray photoelectron spectroscopy

X‐ray photoelectron spectroscopy (XPS) measurements of a Pt/HfO₂(SiO₂)/Si metal‐oxide‐semiconductor (MOS) structure under a bias voltage applied between the gate metal and the silicon substrate were studied. The binding energy shifts of Pt 4f, Hf 4f, O 1s and Si 2p according to the applied voltage were investigated using the MOS structure. After the influence of measurements on the results was carefully examined under various conditions, the amount of the shifts was analyzed from a viewpoint of band alignment. Based on the experimental results, a new way of interpreting the deviation of the electric properties from the ideal ones in a band diagram was proposed. It was demonstrated that the biased XPS is a very powerful method to understand the origin of the electric properties of MOS. Copyright © 2010 John Wiley & Sons, Ltd.     

Conformational and Dynamical Properties of the Isolated,Three‐Dimensional Single‐ and Double‐Tethered Polymer Chain on an Infinite Surface

By Monte Carlo simulations we provide insight into the isolated single‐ and double‐tethered (ST and DT) polymer chain attached to an impenetrable surface to elucidate open theoretical questions and guide future experiments investigating the impact of tethering on the genome packaging by concurrent visualisation of multiple loci along the chromosome(s). In the models, either one or both ends (at a grafting distance d) are fixed or the ST and DT chain are “annealed” by permitting the anchor(s) to diffuse laterally along the surface. We analyse chain self‐entanglement, intrachain segment correlations, the relationship between mean square physical distance and corresponding contour length and provide the first report on the diffusion behaviour.

     

Interface characteristics of a Zr‐based BMG/copper laminated composite

Diffusion bonding of metallic glasses and crystalline metals utilizing excellent superplasticity of monolithic bulk metallic glasses (BMGs) within supercooled liquid region has been found to be an efficient method to improve the room temperature plasticity and fracture toughness of metallic glass. A Zr‐based BMG/copper laminated composite was fabricated by copressing method, and the interface bonding status was characterized by scanning electron microscopy (SEM) and high‐resolution transmission electron microscopy. No void or crack is detected, and the interface is a metallurgical bonding of atomistic level. Although the BMG retains amorphous state after copressing at 390 °C, the region of the amorphous‐crystalline mixture structure with the width of 30–40 nm occurred within the diffusion zone. Copyright © 2013 John Wiley & Sons, Ltd.     

Dynamic Self‐Assembly Adhesion of a Paraquat Droplet on a Pillar[5]arene Surface

The adhesion of herbicide droplets on leaf surfaces plays an important role in the herbicide's adsorption by crops. How to control the adhesive binding which occurs through dynamic self‐assembly between the macroscopic droplet and the surface is a challenging task. We introduce a host onto surfaces that controls the binding of guests in the paraquat droplets. The pillar[5]arene‐functional surface showed the selective binding of paraquat droplets via the host–guest interaction. The work is promising for improving the efficiency of herbicides.     

Interface of ZnS single sheet and substrates: a first‐principles study

Two‐dimensional materials have aroused great interests because of their unique properties not seen in the bulk counterparts. The interface of the ZnS single sheet and substrates are studied in this paper. Different from isolated ZnS single sheet, here in this study, the ZnS single sheet has a remarkable corrugation feature because of the interaction between the ZnS single sheet and the substrate. The top‐site Zn means an attractive reaction with the substrate while the top‐site S means repulsive. For ZnS single sheet/Si(111) interface, the symmetry of the interface does not decrease after geometry optimization because the two layers have a good lattice matching. For ZnS single sheet/Ag(111) interface, an unbalanced interaction (attractive or repulsive) between the ZnS single sheet (Zn or S atom) and Ag surface leads to remarkable corrugation of the ZnS single sheet and the symmetry of the interface decreases. Copyright © 2017 John Wiley & Sons, Ltd.     

Single Oil Drop Electrochemistry on a Screen‐Printed Electrode Surface

The use of a contaminated single oil drop on a screen‐printed carbon electrode is described for the first time here. The simple methodology developed herein opens the possibility of conducting such measurements. R‐(+)‐limonene oil, some samples of which were contaminated with 4‐nitrophenol (4‐NP), was used as the oil phase, and Britton? Robinson (BR) buffer was used as the aqueous phase. An oxidation peak at approximately 0.8 V vs. Ag was obtained when the system comprised an oil/water interface. The charge transfer resistance decreased by a factor of approximately 7.1 when an interfacial system composed of two immiscible liquids was used as an electrochemical tool.     

Metal‐Atom Impact on the Self‐Assembly of Cup‐and‐Ball Metalloporphyrin–Fullerene Conjugates

A fullerene ammonium derivative has been combined with different metalloporphyrin–crown ether receptors to generate very stable supramolecules. The combination of fullerene–porphyrin and ammonium–crown ether interactions leads to a strong chelate effect as evidenced by a high effective molarity (3.16 M ). The different parameters influencing the stability of the supramolecular ensembles, in particular the nature of the metal in the porphyrin moiety, have been rationalized with the help of theoretical calculations thus providing new insights into fullerene–porphyrin interactions.     

Self‐Assembly of Two Agents in a Core‐Shell‐Corona Multicompartment Micelle Studied by Dissipative Particle Dynamics Simulations

Summary: Dissipative particle dynamics simulations are performed on the distributions of two agents in a core‐shell‐corona multicompartment micelle. The simulated results show that when the agents are weakly hydrophobic, their distributions in the multicompartment micelle are largely affected by the interactions between the agents and the blocks; while for strongly hydrophobic agents, the self‐assembly of solubilized species in the micelle is also affected largely by the interactions between the species. This work confirms that a multicompartment micelle can store two agents within separate nanoscopic compartments simultaneously, and shows that the distributions of the agents can be tailored easily by changing the interactions presented. This provides molecular‐level information that is useful for the future rational design of new micellar systems with tailored properties.

Simulated cross sections of the multicompartment micelles with strongly hydrophobic solubilized agents (the solvent and block A are omitted for clarity, block B is dark gray, block C is light gray, agent P is white, and agent Q is black).     

Reversible Control by Light of the High‐Spin Low‐Spin Elastic Interface inside the Bistable Region of a Robust Spin‐Transition Single Crystal

By using a weak modulated laser intensity we have succeeded in reversibly controlling the dynamics of the spin‐crossover (SC) single crystal [{Fe(NCSe)(py)₂}₂(m‐bpypz)] inside the thermal hysteresis. The experiment could be repeated several times with a reproducible response of the high‐spin low‐spin interface and without crystal damage. In‐depth investigations as a function of the amplitude and frequency of the excitation brought to light the existence of a cut‐off frequency ca. 1.5 Hz. The results not only document the applicability of SC materials as actuators, memory devices, or switches, but also open a new avenue for the reversible photo‐control of the spin transition inside the thermal hysteresis.