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
Surface chemistry focuses on the investigation of the adsorption,migration,assembly,activation,reaction,and desorption of atoms and molecules at surfaces.Surface chemistry plays the pivotal roles in both fundamental s...Surface chemistry focuses on the investigation of the adsorption,migration,assembly,activation,reaction,and desorption of atoms and molecules at surfaces.Surface chemistry plays the pivotal roles in both fundamental science and applied technology.This review will summarize the recent progresses on surface assembly,synthesis and catalysis investigated mainly by scanning tunneling microscopy and atomic force microscopy.Surface assemblies of water and small biomolecules,construction of Sierpin′ski triangles and surface chirality are summarized.On-surface synthesis of conjugated carbo-and heterocycles and other kinds of carbon nanostructures are surveyed.Surface model catalysis,including single-atom catalysis and electrochemical catalysis,are discussed at the single-atom level.展开更多
The diffusing behavior of water through alkyd coatings with different pigment volume concentration (PVC) has been studied by EIS and SEM techniques. The corresponding diffusion coefficients were also calculated. The e...The diffusing behavior of water through alkyd coatings with different pigment volume concentration (PVC) has been studied by EIS and SEM techniques. The corresponding diffusion coefficients were also calculated. The experimental results showed that, in 0.5 mol· L－ 1 NaCl solution, the diffusion process of water through alkyd coatings with different PVC followed the ideal-Fick′ s law in the initial period.Within the PVC value concerned, the diffusion coefficients initially decreased with the increase of PVC parameter, reaching a minimum value at 60％ , which is the CPVC of micaceous iron oxide, and then increased with the PVC increase. When the PVC was less than CPVC, the barrier property produced by the pigment was the main factor that affected the water diffusion behavior. However, the microstructure of the alkyd coatings played an important role when the PVC was greater than CPVC.展开更多
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.
基金supported by the National Natural Science Foundation of China(Nos.22225202,92356309,22132007,21991132,22172002)。
文摘Surface chemistry focuses on the investigation of the adsorption,migration,assembly,activation,reaction,and desorption of atoms and molecules at surfaces.Surface chemistry plays the pivotal roles in both fundamental science and applied technology.This review will summarize the recent progresses on surface assembly,synthesis and catalysis investigated mainly by scanning tunneling microscopy and atomic force microscopy.Surface assemblies of water and small biomolecules,construction of Sierpin′ski triangles and surface chirality are summarized.On-surface synthesis of conjugated carbo-and heterocycles and other kinds of carbon nanostructures are surveyed.Surface model catalysis,including single-atom catalysis and electrochemical catalysis,are discussed at the single-atom level.
文摘The diffusing behavior of water through alkyd coatings with different pigment volume concentration (PVC) has been studied by EIS and SEM techniques. The corresponding diffusion coefficients were also calculated. The experimental results showed that, in 0.5 mol· L－ 1 NaCl solution, the diffusion process of water through alkyd coatings with different PVC followed the ideal-Fick′ s law in the initial period.Within the PVC value concerned, the diffusion coefficients initially decreased with the increase of PVC parameter, reaching a minimum value at 60％ , which is the CPVC of micaceous iron oxide, and then increased with the PVC increase. When the PVC was less than CPVC, the barrier property produced by the pigment was the main factor that affected the water diffusion behavior. However, the microstructure of the alkyd coatings played an important role when the PVC was greater than CPVC.
