Directly correlating the morphology and composition of interfacial water is vital not only for studying water icing under critical conditions but also for understanding the role of protein–water interac-tions in bio-...Directly correlating the morphology and composition of interfacial water is vital not only for studying water icing under critical conditions but also for understanding the role of protein–water interac-tions in bio-relevant systems.In this study,we present a model system to study two-dimensional(2D)water layers under ambient conditions by using self-assembled monolayers(SAMs)supporting the physisorp-tion of the Cytochrome C(Cyt C)protein layer.We observed that the 2D island-like water layers were uniformly distributed on the SAMs as characterized by atomic force microscopy,and their composition was confirmed by nano-atomic force microscopy-infrared spectroscopy and Raman spectroscopy.In addition,these 2D flakes could grow under high-humidity conditions or melt upon the introduction of a heat source.The formation of these flakes is attributed to the activation energy for water desorption from the Cyt C being nearly twofold high than that from the SAMs.Our results provide a new and effective method for further understanding the water–protein interactions.展开更多
Microemulsions are usually used to prepare nanomaterials.The fo rmation behavior of microemulsions is crucial to the preparation of nanomaterials.Water in the internal phase is usually replaced by electrolyte solution...Microemulsions are usually used to prepare nanomaterials.The fo rmation behavior of microemulsions is crucial to the preparation of nanomaterials.Water in the internal phase is usually replaced by electrolyte solutions to prepare nanomaterials.Knowing the effects of electrolyte solution on the phase behavior of microemulsion is significant to the nanomaterial preparation.Microemulsion systems were studied by a conductivity method with cyclohexane as oil,Triton X-100 as surfactant,hexanol as cosurfactant,and deionized water or the electrolyte solutions of Cu(Ac)_(2)and Zn(Ac)_(2)as aqueous phases.The results showed that the replacement of water with electrolyte solution had a strong effect on the phase behavior of microemulsion system.The O/W microemulsion zone in water system was not observed in the studied electrolyte system.The shape and area of the corresponding phase zone in electrolyte system were different from that in water system.The microemulsion regions of electrolyte solution systems were always larger than that of water system.Zn(Ac)_(2)showed a larger microemulsion region than Cu(Ac)_(2)at 0.1 mol·L^(-1).The microemulsion phase region formed by 0.1 mol·L^(-1)Zn(Ac)_(2)+0.1 mol·L^(-1)Cu(Ac)_(2)was smaller than that formed by 0.1 mol·L^(-1)Zn(Ac)_(2)or 0.1 mol·L^(-1)Cu(Ac)_(2)lonely.With the increase of electrolyte concentration in the electrolyte solution and the rise of temperature,the microemulsion region shrank gradually.The changes of interactions between different components in the system should be responsible to the variation of phase behavior.The results provide important information for the microemulsion system with electrolyte solution as aqueous phase.展开更多
本研究通过计算机模拟构建三维立方格点模型模拟多嵌段高分子链在条纹表面的动态吸附过程。模拟研究基于动态蒙特卡罗方法,系统分析了温度、嵌段长度和条纹宽度对吸附机制的影响。模拟研究发现,相较于均质链在异构表面,多嵌段高分子链...本研究通过计算机模拟构建三维立方格点模型模拟多嵌段高分子链在条纹表面的动态吸附过程。模拟研究基于动态蒙特卡罗方法,系统分析了温度、嵌段长度和条纹宽度对吸附机制的影响。模拟研究发现,相较于均质链在异构表面,多嵌段高分子链在条纹表面的吸附行为与之存在许多差异。多嵌段高分子链以及条纹表面的特殊结构使得高分子链吸附到表面的机会受到影响,对比于均质链,多嵌段链存在更多更加复杂的构象情况,低温下多嵌段链通过选择性吸附形成“U形”和“拉链”等特殊构象,其临界吸附温度与嵌段序列及表面图案的匹配性密切相关,揭示了嵌段长度与条纹宽度的协同作用对吸附行为的非线性调控机制。In this study, a three-dimensional lattice point model was constructed to simulate the dynamic adsorption process of multi-block polymer chains on stripe surfaces. Based on the dynamic Monte Carlo method, the effects of temperature, block length and stripe width on the adsorption mechanism were systematically analyzed. The simulation results show that the adsorption behavior of multi-block polymer chains on stripe surface is different from that of homogeneous chains on heterogeneous surface. The special structure of the multi-block polymer chain and the striped surface affects the adsorption chance of the polymer chain to the surface. Compared with the homogeneous chain, the multi-block chain has more and more complex conformations. At low temperature, the multi-block chain forms special conformations such as “U-shape” and “zipper” through selective adsorption, and the critical adsorption temperature is closely related to the matching of block sequence and surface pattern. The nonlinear mechanism of the synergistic effect of block length and stripe width on adsorption behavior was revealed.展开更多
We study the effects of gas adsorption on the dynamics and stability of nanobubbles at the solid–liquid interface. The phase diagram and dynamic evolution of surface nanobubbles were analyzed under varying equilibriu...We study the effects of gas adsorption on the dynamics and stability of nanobubbles at the solid–liquid interface. The phase diagram and dynamic evolution of surface nanobubbles were analyzed under varying equilibrium adsorption constant.Four distinct dynamic behaviors appear in the phase diagram: shrinking to dissolution, expanding to bursting, shrinking to stability, and expanding to stability. Special boundary states are identified in phase diagram, where the continuous growth of nanobubbles can take place even under very weak gas–surface interaction or with very small initial bubble size. Surface adsorption plays a critical role in the stability, lifetime, radius, and contact angle of nanobubbles, thereby demonstrating that pinning is not a prerequisite for stabilization. Furthermore, stable equilibrium nanobubbles exhibit a characteristic range of footprint radius, a limited height, and a small contact angle, consistent with experimental observations.展开更多
Alkanes are present in the atmosphere,commonly in the form of aerosols,and can thus interact with water droplets,leading to the formation of new interfaces.Yet,in the study of these interactions,traditional experiment...Alkanes are present in the atmosphere,commonly in the form of aerosols,and can thus interact with water droplets,leading to the formation of new interfaces.Yet,in the study of these interactions,traditional experimental methods often rely on the presence of sample containers,which can interfere with the observations.Acoustic levitation is a technique which allows the manipulation of samples in the microliter regime in a contact-free manner.Hence,interfacial phenomena can be studied without the presence of external surfaces,mimicking atmospheric conditions.Herein,we acoustically levitated a droplet of water in contact with a droplet of hexadecane and observed interfacial crystallization at the hexadecane/water interface that propagated to the entire droplet of hexadecane.It was found that the crystallization occurred up to 3 K above the melting temperature of hexadecane,and at a relative humidity below 30%.Moreover,the volume ratio between water and hexadecane influenced the fraction of crystallized surface area;for a hexadecane:water ratio above 1:2 full surface crystallization occurred.Combining acoustic levitation with Raman spectroscopy allowed the characterization of the phase transition in real time,demonstrating the existence of a solid crystal of alkane upon water evaporation.This study provides insights into the process of interfacial crystallization of hexadecane and demonstrates the suitability of acoustic levitation to study contact-free interfacial phenomena between two immiscible liquids.展开更多
基金supported by the National Natural Science Foundation of China(22273045,52488101 and 22472043)Ningbo Youth Science and Technology Innovation Leading Talent(2023QL041)Tsinghua University Independent Scientific Research Plan for Young Investigator,Tsinghua University Dushi Program,and Initiative Scientific Research Program。
文摘Directly correlating the morphology and composition of interfacial water is vital not only for studying water icing under critical conditions but also for understanding the role of protein–water interac-tions in bio-relevant systems.In this study,we present a model system to study two-dimensional(2D)water layers under ambient conditions by using self-assembled monolayers(SAMs)supporting the physisorp-tion of the Cytochrome C(Cyt C)protein layer.We observed that the 2D island-like water layers were uniformly distributed on the SAMs as characterized by atomic force microscopy,and their composition was confirmed by nano-atomic force microscopy-infrared spectroscopy and Raman spectroscopy.In addition,these 2D flakes could grow under high-humidity conditions or melt upon the introduction of a heat source.The formation of these flakes is attributed to the activation energy for water desorption from the Cyt C being nearly twofold high than that from the SAMs.Our results provide a new and effective method for further understanding the water–protein interactions.
基金funded by the National Natural Science Foundation of China(22078203)fundamental research funds for the central universities(2022SCUH0041)。
文摘Microemulsions are usually used to prepare nanomaterials.The fo rmation behavior of microemulsions is crucial to the preparation of nanomaterials.Water in the internal phase is usually replaced by electrolyte solutions to prepare nanomaterials.Knowing the effects of electrolyte solution on the phase behavior of microemulsion is significant to the nanomaterial preparation.Microemulsion systems were studied by a conductivity method with cyclohexane as oil,Triton X-100 as surfactant,hexanol as cosurfactant,and deionized water or the electrolyte solutions of Cu(Ac)_(2)and Zn(Ac)_(2)as aqueous phases.The results showed that the replacement of water with electrolyte solution had a strong effect on the phase behavior of microemulsion system.The O/W microemulsion zone in water system was not observed in the studied electrolyte system.The shape and area of the corresponding phase zone in electrolyte system were different from that in water system.The microemulsion regions of electrolyte solution systems were always larger than that of water system.Zn(Ac)_(2)showed a larger microemulsion region than Cu(Ac)_(2)at 0.1 mol·L^(-1).The microemulsion phase region formed by 0.1 mol·L^(-1)Zn(Ac)_(2)+0.1 mol·L^(-1)Cu(Ac)_(2)was smaller than that formed by 0.1 mol·L^(-1)Zn(Ac)_(2)or 0.1 mol·L^(-1)Cu(Ac)_(2)lonely.With the increase of electrolyte concentration in the electrolyte solution and the rise of temperature,the microemulsion region shrank gradually.The changes of interactions between different components in the system should be responsible to the variation of phase behavior.The results provide important information for the microemulsion system with electrolyte solution as aqueous phase.
文摘本研究通过计算机模拟构建三维立方格点模型模拟多嵌段高分子链在条纹表面的动态吸附过程。模拟研究基于动态蒙特卡罗方法,系统分析了温度、嵌段长度和条纹宽度对吸附机制的影响。模拟研究发现,相较于均质链在异构表面,多嵌段高分子链在条纹表面的吸附行为与之存在许多差异。多嵌段高分子链以及条纹表面的特殊结构使得高分子链吸附到表面的机会受到影响,对比于均质链,多嵌段链存在更多更加复杂的构象情况,低温下多嵌段链通过选择性吸附形成“U形”和“拉链”等特殊构象,其临界吸附温度与嵌段序列及表面图案的匹配性密切相关,揭示了嵌段长度与条纹宽度的协同作用对吸附行为的非线性调控机制。In this study, a three-dimensional lattice point model was constructed to simulate the dynamic adsorption process of multi-block polymer chains on stripe surfaces. Based on the dynamic Monte Carlo method, the effects of temperature, block length and stripe width on the adsorption mechanism were systematically analyzed. The simulation results show that the adsorption behavior of multi-block polymer chains on stripe surface is different from that of homogeneous chains on heterogeneous surface. The special structure of the multi-block polymer chain and the striped surface affects the adsorption chance of the polymer chain to the surface. Compared with the homogeneous chain, the multi-block chain has more and more complex conformations. At low temperature, the multi-block chain forms special conformations such as “U-shape” and “zipper” through selective adsorption, and the critical adsorption temperature is closely related to the matching of block sequence and surface pattern. The nonlinear mechanism of the synergistic effect of block length and stripe width on adsorption behavior was revealed.
基金Project supported by the Natural Science Foundation of Guangxi Zhuang Autonomous Region, China (Grant No. 2022GXNSFAA035487)the National Natural Science Foundation of China (Grant Nos. 12272100, 11474285, and 12074382)+2 种基金the Graduate Education Innovation Project of Guangxi Zhuang Autonomous Region, China (Grant No. XJCY2022012)the Guangxi Normal University Ideological and Political Demonstration Course Construction Project (Grant Nos. 2022kcsz15 and 2023kcsz29)the Innovation Project of Graduate Education of Guangxi Zhuang Autonomous Region, China (Grant No. YCBZ2024087)。
文摘We study the effects of gas adsorption on the dynamics and stability of nanobubbles at the solid–liquid interface. The phase diagram and dynamic evolution of surface nanobubbles were analyzed under varying equilibrium adsorption constant.Four distinct dynamic behaviors appear in the phase diagram: shrinking to dissolution, expanding to bursting, shrinking to stability, and expanding to stability. Special boundary states are identified in phase diagram, where the continuous growth of nanobubbles can take place even under very weak gas–surface interaction or with very small initial bubble size. Surface adsorption plays a critical role in the stability, lifetime, radius, and contact angle of nanobubbles, thereby demonstrating that pinning is not a prerequisite for stabilization. Furthermore, stable equilibrium nanobubbles exhibit a characteristic range of footprint radius, a limited height, and a small contact angle, consistent with experimental observations.
基金the financial support from the Swedish Research Council(VR)(Public,Sweden)the Swedish Foundation for Strategic Research(SSF)(Non-Profit,Sweden)。
文摘Alkanes are present in the atmosphere,commonly in the form of aerosols,and can thus interact with water droplets,leading to the formation of new interfaces.Yet,in the study of these interactions,traditional experimental methods often rely on the presence of sample containers,which can interfere with the observations.Acoustic levitation is a technique which allows the manipulation of samples in the microliter regime in a contact-free manner.Hence,interfacial phenomena can be studied without the presence of external surfaces,mimicking atmospheric conditions.Herein,we acoustically levitated a droplet of water in contact with a droplet of hexadecane and observed interfacial crystallization at the hexadecane/water interface that propagated to the entire droplet of hexadecane.It was found that the crystallization occurred up to 3 K above the melting temperature of hexadecane,and at a relative humidity below 30%.Moreover,the volume ratio between water and hexadecane influenced the fraction of crystallized surface area;for a hexadecane:water ratio above 1:2 full surface crystallization occurred.Combining acoustic levitation with Raman spectroscopy allowed the characterization of the phase transition in real time,demonstrating the existence of a solid crystal of alkane upon water evaporation.This study provides insights into the process of interfacial crystallization of hexadecane and demonstrates the suitability of acoustic levitation to study contact-free interfacial phenomena between two immiscible liquids.
