Evaporation Of Water Molecules Research Articles

Self-encapsulated ionic fibers based on stress-induced adaptive phase transition for non-contact depth-of-field camouflage sensing

Ionically conductive fibers have promising applications; however, complex processing techniques and poor stability limit their practicality. To overcome these challenges, we proposed a stress-induced adaptive phase transition strategy to conveniently fabricate self-encapsulated hydrogel-based ionically conductive fibers (se-HICFs). se-HICFs can be produced simply by directly stretching ionic hydrogels with ultra-stretchable networks (us-IHs) or by dip-drawing from molten us-IHs. During this process, stress facilitated the directional migration and evaporation of water molecules in us-IHs, causing a phase transition in the surface layer of ionic fibers to achieve self-encapsulation. The resulting sheath-core structure of se-HICFs enhanced mechanical strength and stability while endowing se-HICFs with powerful non-contact electrostatic induction capabilities. Mimicking nature, se-HICFs were woven into spider web structures and camouflaged in wild environments to achieve high spatiotemporal resolution 3D depth-of-field sensing for different moving media. This work opens up a convenient route to fabricate stable functionalized ionic fibers.

D-Amino acid recognition of tripeptides studied by ultraviolet photodissociation spectroscopy of hydrogen-bonded clusters.

To understand the roles of D-amino acids, evaluating their chemical properties in living organisms is essential. Herein, D-amino acid recognition of peptides was investigated using a tandem mass spectrometer equipped with an electrospray ionization source and a cold ion trap. Ultraviolet (UV) photodissociation spectroscopy and water adsorption of hydrogen-bonded protonated clusters of tryptophan (Trp) enantiomers and tripeptides (SAA, ASA, and AAS, where S and A denote L-serine and L-alanine, respectively) were carried out at 8K in the gas phase. In the UV photodissociation spectrum of H+(D-Trp)ASA, the bandwidth of the S1-S0 transition, which corresponds to the ππ* state of the Trp indole ring, was narrower than those of the other five clusters, H+(D-Trp)SAA, H+(D-Trp)AAS, H+(L-Trp)SAA, H+(L-Trp)ASA, and H+(L-Trp)AAS. In the UV photoexcitation of H+(D-Trp)ASA(H2O)n, which were formed via water adsorption on gas-phase H+(D-Trp)ASA, the evaporation of water molecules was the main photodissociation pathway. An NH2CHCOOH-eliminated ion and H+ASA were observed in the product ion spectrum. By contrast, water molecules adsorbed on the other five clusters remained on the product ions for NH2CHCOOH elimination and Trp detachment after the UV photoexcitation. The results indicated that the indole ring of Trp was located on the surface of H+(D-Trp)ASA, and the amino and carboxyl groups of Trp formed hydrogen bonds in H+(D-Trp)ASA. For the other five clusters, the indole rings of Trp were hydrogen bonded in the clusters, and the amino and carboxyl groups of Trp were present on the cluster surfaces.

Accelerating water evaporation from salty droplets on polar substrate: a molecular dynamics study.

Evaporation of seawater containing various ions is the largest source of rainfall, affecting the global climate. In industrial areas, water evaporation finds applications in the desalination of seawater to get fresh water for arid coastal regions. Understanding how ions and substrates influence the evaporation of sessile salty droplets on a substrate is essential to modulate the evaporation rate. In the present study, we investigate the effect of ions (Mg2+, Na+, Cl-) on the evaporation of water molecules from sessile droplets on the solid surface using molecular dynamics simulations. The electrostatic interactions between water molecules and ions suppress water evaporation. However, the interactions between molecules and atoms in the substrates accelerate the evaporation. We increase the evaporation of salty droplets by 21.6% by placing the droplet on the polar substrate.

Chemical properties of inner and surficial regions of hydrogen-bonded clusters of biological molecules: ultraviolet photodissociation and water adsorption analyses in the gas phase.

The chemical and physical properties of cold, gas-phase hydrogen-bonded clusters of L-alanine (L-Ala), L-trialanine (L-Ala3), L-tetraalanine (L-Ala4), and tryptophan (Trp) enantiomers were investigated using tandem mass spectrometry with an electrospray ionization source and cold ion trap. From the ultraviolet (UV) photodissociation spectra at 265-290nm, the electronic structures of homochiral H+(L-Trp)(L-Ala) at 8K were found to be different from those of heterochiral H+(D-Trp)(L-Ala) and protonated Trp. The number of water molecules adsorbed on the surface of gas-phase H+(D-Trp)(L-Ala) was larger than that of H+(L-Trp)(L-Ala), indicating stronger intermolecular interactions of L-Ala with H+(L-Trp) than those with H+(D-Trp). The product ion spectrum obtained by 265nm photoexcitation of H+(L-Trp)(L-Ala3)(H2O)n formed via gas-phase water adsorption on H+(L-Trp)(L-Ala3) showed that the evaporation of water molecules was the main photodissociation process. In the case of H+(L-Trp)(L-Ala4)(H2O)n, signals of H+(L-Ala4) (H2O)n formed via L-Trp evaporation were observed in the product ion spectra, and the cross-section for UV photoinduced L-Trp evaporation became larger as the number of adsorbed water molecules increased. This observation indicates that water molecules were selectively adsorbed on the H+(L-Ala4) side of H+(L-Trp)(L-Ala4) and weakened the intermolecular interactions between L-Trp and H+(L-Ala4) in the hydrogen-bonded cluster.

Impacts of Climate Change on the Plant Water Interactions

Climate change has an impact on ecosystem structure and function globally by altering the relationships between plants and soil organisms. Despite the fact that water is the most plentiful molecule on Earth's surface, water scarcity is the element that most severely limits global terrestrial plant production. Little is known about the climatic factors that drive phenological responses to climate change, and less attention has been paid to the fact that phenology is also responsive to other climatic. The aim of this study was to assess the impacts of climate change on plant water interactions. This study was guided by the specific objectives, which included examining the relationship between climate change and plant function; finding out the impacts of climate change on plant water interactions; and assessing how plants handle water scarcity. It was found that there was a linkage between climate change and plant function. The evaporation of water molecules from the outer surfaces of the mesophyll cells initiates the upward transpiration pull in the leaves, and respiring starches and sugars are created during photosynthetic processes using sunlight energy. Climate change enhanced the most enormous movement of species that has occurred without direct human intervention. It was also found that precipitation was a key driver of phenological changes in desert ecosystems. It was also found that drought was one of the most significant biotic challenges faced by plants, with considerable genetic variation in water deficit responses. There is a need for research on climate change to ease biodiversity conservation. Keywords: Climate change, Plant water interactions, Plant, Water DOI: 10.7176/JRDM/87-01 Publication date: September 30 th 2022

Multi-scale deformation characteristics and mechanism of red-bed mudstone in dry-wet environment

Repeated swelling-shrinking behaviors of red-bed mudstone poses a potential threat to high-speed railways. Through swelling test and dry-wet cycle test, the deformation law of mudstone samples was discussed. Using X-ray CT scanning, MIP and BET technology, the inner relationship between deformation and structural characteristics were clarified. The results showed that the surface of sample was chipped and peeled off after two cycles. During the dehumidification, the mudstone has undergone three stages of shrinkage adjustment, accelerated shrinkage and stable shrinkage. Uneven tensile stress caused by evaporation of water molecules in the initial stage of drying delayed the shrinkage. Initial water content was opposite to the changes of stable strain after water immersion and residual strain after dehydration, while it was positively correlated with environmental temperature. Porosity and connectivity keep increasing with the continuous cycle, and the number appeared to gradually descend from the two ends to the middle in space. Successive drying and wetting promoted a wider range of diameter-length ratio by the swelling of hydrophilic minerals and uneven shrinkage stress. Spatial orientation also transitioned to the polar angle. Specifically, the structure evolved from the layered shape to the tree-like and net-like in order. Microscopic scale mainly included uniform flat pores and wedge-shaped capillary pores, ranging from 10 to 80 Å. The number of cycles didn’t affect the morphology of micropores, but only caused volume and specific surface area to enlarge. The existence of clays generated irreversible deformation of micropores and initiated the gradual extension. This work will provide key data and necessary methods for the geohazard problems.

Effect of Microhydration on the Temporary Anion States of Pyrene.

The influence of incremental hydration (≤4) on the electronic resonances of the pyrene anion is studied using two-dimensional photoelectron spectroscopy. The photoexcitation energies of the resonances do not change; therefore, from the anion’s perspective, the resonances remain the same, but from the neutral’s perspective of the electron–molecule reaction, the resonances decrease in energy by the binding energy of the water molecules. The autodetachment of the resonances shows that hydration has very little effect, showing that even the dynamics of most of the resonances are not impacted by hydration. Two specific resonances do show changes that are explained by the closing of specific autodetachment channels. The lowest-energy resonance leads to efficient electron capture as observed through thermionic emission and evaporation of water molecules (dissociative electron attachment). The implications of low-energy electron capture in dense molecular interstellar clouds are discussed.

Synthesis of nitrogen-doped carbon embedded TiO2 films for electrochromic energy storage application

The nitrogen-doped carbon embedded nanoporous TiO2 electrode is synthesized by a sol-gel technique assisted the amide condensation reaction for multifunction electrochromic energy storage device. By controlling the content of oleylamine (2.0 wt%), the nitrogen-doped carbon embedded nanoporous TiO2 film has the optimal surface nanoporous morphology (2.0OL-TiO2) and the excellent electrochromic energy storage properties, such as the high coloration efficiency (69.6 cm2 C−1), the short switching time (bleaching time of 4.7 s and coloration time of 5.6 s) and the large specific capacitance (127.5 F g−1) at a current density of 2 A g−1. These fascinating properties are mainly attributed to the optimal surface nanoporous morphology which can improve the electrochemical activity. Here, the nanoporous structure is generated by the evaporation of water molecules which are formed in the amide condensation reaction. In addition, the nitrogen-doped carbon leads to an enhancement in electrical conductivity during the multimeric amide condensation reaction. The results show that the nitrogen-doped carbon can provide adequate ion and electron transport pathways. Therefore, it is worth believing that the research is of great significance to realize the electrode design of multifunctional electrochromic energy storage device.

Thermal Properties of Sago Fiber-Epoxy Composite

The aim of this study is to analyze the thermal properties of sago fiber-epoxy composite. The sago fiber-based composite has been prepared using epoxy resin as the matrix, via a simple mixing followed by compression. The compression process includes hot compression (100 °C/10 kgf cm−2) and cold compression (ambient/10 kgf cm−2). The composite series was prepared with 9%, 13%, 17%, 20%, and 23% (w/w) of epoxy resin. Microstructures of all materials used were observed using an SEM (scanning electron microscope) instrument. The thermal properties of the composite and its components were examined through TG/DTA characterization. The samples were heated using the heating rate of 10 °C/min from room temperature to 400 °C, except for epoxy resin, which was heated to 530 °C. TG/DTA results depict three stages of thermal processes of sago fiber-epoxy composite: evaporation of water molecules at below 100 °C with the peak point within the range of 51.3 and 57.3 °C, the damage of sago fiber within the range of 275 and 370 °C with the peak point within the range of 333.3 and 341.3 °C and the damage of epoxy resin at above 350 °C with the peak point at 376.2 °C.

Impact of a hydrophobic ion on the early stage of atmospheric aerosol formation

Atmospheric aerosols are one of the major factors affecting planetary climate, and the addition of anthropogenic molecules into the atmosphere is known to strongly affect cloud formation. The broad variety of compounds present in such dilute media and their specific underlying thermalization processes at the nanoscale make a complete quantitative description of atmospheric aerosol formation certainly challenging. In particular, it requires fundamental knowledge about the role of impurities in water cluster growth, a crucial step in the early stage of aerosol and cloud formation. Here, we show how a hydrophobic pyridinium ion within a water cluster drastically changes the thermalization properties, which will in turn change the corresponding propensity for water cluster growth. The combination of velocity map imaging with a recently developed mass spectrometry technique allows the direct measurement of the velocity distribution of the water molecules evaporated from excited clusters. In contrast to previous results on pure water clusters, the low-velocity part of the distributions for pyridinium-doped water clusters is composed of 2 distinct Maxwell-Boltzmann distributions, indicating out-of-equilibrium evaporation. More generally, the evaporation of water molecules from excited clusters is found to be much slower when the cluster is doped with a pyridinium ion. Therefore, the presence of a contaminant molecule in the nascent cluster changes the energy storage and disposal in the early stages of gas-to-particle conversion, thereby leading to an increased rate of formation of water clusters and consequently facilitating homogeneous nucleation at the early stages of atmospheric aerosol formation.

Humidity responsive single-layered film fabricated by hydrophilic titanium oxide nanotubes

We fabricated a humidity responsive film comprising a bundle of titanium oxide tubes, which changes its curvature corresponding to the relative humidity. The mechanism of changing the curvature of the film can be explained by adsorption, condensation, and evaporation of water molecules within the film. During adsorption, a liquid bridge is formed because of the growth of a water layer between tubes, thus contracting the tubes. When vapor pressure exceeds the equilibrium vapor pressure, condensation occurs at the meniscus of the liquid bridge, thus expanding the gap between tubes. We obtained the adsorption and desorption isotherms for the humidity responsive film by determining physical adsorption. Additionally, we demonstrated the varying motions of the humidity sensing film when a water droplet was applied on the surface. The sensor could distinguish between saturated and oversaturated humidity conditions, such as fog and rain, respectively, which is not possible using resistive humidity sensors. This humidity responsive film can be applied to environmental monitoring systems and possibly even to energy harvesting systems.

Sequential evaporation of water molecules from protonated water clusters: measurement of the velocity distributions of the evaporated molecules and statistical analysis.

Velocity distributions of neutral water molecules evaporated after collision induced dissociation of protonated water clusters H+(H2O)n≤10 were measured using the combined correlated ion and neutral fragment time-of-flight (COINTOF) and velocity map imaging (VMI) techniques. As observed previously, all measured velocity distributions exhibit two contributions, with a low velocity part identified by statistical molecular dynamics (SMD) simulations as events obeying the Maxwell-Boltzmann statistics and a high velocity contribution corresponding to non-ergodic events in which energy redistribution is incomplete. In contrast to earlier studies, where the evaporation of a single molecule was probed, the present study is concerned with events involving the evaporation of up to five water molecules. In particular, we discuss here in detail the cases of two and three evaporated molecules. Evaporation of several water molecules after CID can be interpreted in general as a sequential evaporation process. In addition to the SMD calculations, a Monte Carlo (MC) based simulation was developed allowing the reconstruction of the velocity distribution produced by the evaporation of m molecules from H+(H2O)n≤10 cluster ions using the measured velocity distributions for singly evaporated molecules as the input. The observed broadening of the low-velocity part of the distributions for the evaporation of two and three molecules as compared to the width for the evaporation of a single molecule results from the cumulative recoil velocity of the successive ion residues as well as the intrinsically broader distributions for decreasingly smaller parent clusters. Further MC simulations were carried out assuming that a certain proportion of non-ergodic events is responsible for the first evaporation in such a sequential evaporation series, thereby allowing to model the entire velocity distribution.

Collision-induced evaporation of water clusters and contribution of momentum transfer

The evaporation of water molecules from high-velocity argon atoms impinging on protonated water clusters has been computationally investigated using molecular dynamics simulations with the reactive OSS2 potential to model water clusters and the ZBL pair potential to represent their interaction with the projectile. Swarms of trajectories and an event-by-event analysis reveal the conditions under which a specific number of molecular evaporation events is found one nanosecond after impact, thereby excluding direct knockout events from the analysis. These simulations provide velocity distributions that exhibit two main features, with a major statistical component arising from a global redistribution of the collision energy into intermolecular degrees of freedom, and another minor but non-ergodic feature at high velocities. The latter feature is produced by direct impacts on the peripheral water molecules and reflects a more complete momentum transfer. These two components are consistent with recent experimental measurements and confirm that electronic processes are not explicitly needed to explain the observed non-ergodic behavior.

DFT(B3LYP/LanL2DZ), non-linear optical and electrical studies of a new hybrid compound: [C6H10(NH3)2]CoCl4·H2O

A new organic-inorganic material [C6H10(NH3)2]CoCl4·H2O was reported. The title compound was synthesized at room temperature by slow evaporation and then characterized by a single X-ray diffraction, spectroscopic measurements, thermal analysis and dielectric technique. It crystallizes in the non-centrosymmetric space group Pna21 with the following unit cell parameters: a=12.5328(1) Å, b=9.0908(1) Å, c=11.7440(1) and α=β=γ=90°. The structure can be described by the alternation of two different cationic-anionic layers. It consists of isolated H2O, isolated [CoCl4]2− tetrahedral anions and diammoniumcyclohexane [C6H10(NH3)2]2+ cations, which are connected via N–H…Cl, N–H…O and O–H…N hydrogen bonds. The Hirshfeld surface analysis was conducted to investigate intermolecular interactions and associated 2D fingerprint plots, revealing the relative contribution of these interactions in the crystal structure quantitatively. Theoretical calculations were performed using DFT/B3LYP/LanL2DZ method for studying the molecular structure and vibrational spectra and especially to examine the non-linear optical behavior of the compound. Solid state 13C NMR spectrum shows three signals correspond to three different carbon environments. Thermal analysis discloses a phase transition at the temperature 315K and the evaporation of water molecule at 327K. A detailed dielectric study was reported and shows a good agreement with thermal measurements.

Proton Migration in Clusters Consisting of Protonated Pyridine Solvated by Water Molecules.

Proton transfer (PT) from protonated pyridine to water molecules is observed after excitation of microhydrated protonated pyridine (Py) clusters PyH(+) (H2 O)n (n=0-5) is induced by a single collision with an Ar atom at high incident velocity (95×10(3) m s(-1) ). Besides the fragmentation channel associated with the evaporation of water molecules, the charged-fragment mass spectrum shows competition between the production of the PyH(+) ion (or its corresponding charged fragments) and the production of H(+) (H2 O) or H(+) (H2 O)2 ions. The increase in the production of protonated water fragments as a function of the number of H2 O molecules in the parent cluster ion as well sd the observation of a stable H(+) (H2 O)2 fragment, even in the case of the dissociation of PyH(+) (H2 O)2 , are evidence of the crucial role of PT in the relaxation process, even for a small number of solvating water molecules.

Smart textile plasmonic fiber dew sensors.

We propose a novel Surface Plasmon Resonance (SPR)-based sensor that detects dew formation in optical fiber-based smart textiles. The proposed SPR sensor facilitates the observation of two phenomena: condensation of moisture and evaporation of water molecules in air. This sensor detects dew formation in less than 0.25 s, and determines dew point temperature with an accuracy of 4%. It can be used to monitor water layer depth changes during dew formation and evaporation in the range of a plasmon depth probe, i.e., 250 nm, with a resolution of 7 nm. Further, it facilitates estimation of the relative humidity of a medium over a dynamic range of 30% to 70% by measuring the evaporation time via the plasmon depth probe.

Bubble Formation on the Surface of Laser-Irradiated Nanosized Particles

It is well known that a phase transition from liquid to vapor occurs in the thermal boundary layer adjacent to a nanoparticle that has a high temperature upon irradiation with a high-power laser. In this study, the mechanism by which the evaporated layer adjacent to a laser-irradiated nanoparticle can grow as a bubble was investigated through detailed calculations. The pressure of the evaporated liquid volume due to heat diffusion from the irradiated nanoparticle was estimated using a bubble nucleation model based on molecular interactions. The bubble wall motion was obtained using the Keller-Miksis equation. The density and temperature inside the bubble were obtained by solving the continuity and energy equation for the vapor inside the bubble. The evaporation of water molecules or condensation of water vapor at the vapor–liquid interface and the homogeneous nucleation of vapor were also considered. The calculated bubble radius-time curve for the bubble formed on the surface of a gold particle with a diameter of 9 nm is close to the experimental result. Our study reveals that an appropriate size of the evaporated liquid volume and a large expansion velocity are important parameters for the formation of a transient nanosized bubble. The calculation result suggests that homogeneous condensation of vapor rather than condensation at the interface occurs.

Organic Synthesis in the Interstellar Medium by Low-Energy Carbon Irradiation

We present a first principles molecular dynamics (FPMD) study of the interaction of low-energy neutral carbon projectiles with amorphous solid water clusters at 30 K. Reactions involving the carbon atom at an initial energy of 11 and 1.7 eV with 30-molecule clusters have been investigated. Simulations indicate that the formation of hydroxymethylene, an intermediate in formaldehyde production, dominates at the higher energy. The reaction proceeds by fragmenting a water molecule, binding the carbon to the OH radical, and saturating the C valence with a hydrogen atom that can arise from the originally dissociated water molecule, or through a chain of proton transfer events. We identified several possible pathways for the formation of HCOH. When the initial collision occurs at the periphery of the cluster, we observe the formation of CO and the evaporation of water molecules. At the lower energy water fragmentation is not favorable, thus leading to the formation of weakly bound carbon-water complexes.

Molecular dynamics of electrosprayed water nanodroplets containing sodium bis(2‐ethylhexyl)sulfosuccinate

The behavior of aqueous solutions of sodium bis(2-ethylhexyl)sulfosuccinate (AOTNa) subject to electrospray ionization (ESI) has been investigated by molecular dynamics (MD) simulations at three temperatures (350, 500 and 800 K). We consider several types of water nanodroplets containing AOTNa molecules and composed of a fixed number of water molecules (1000), N(AOT)(0) AOT(-) anions (N(AOT)(0) = 0, 5, 10) and N(Na)(0) sodium ions (N(Na)(0) = 0, 5, 10, 15, 20): in a short time scale (less than 1 ns), the AOTNa molecules, initially forming direct micelles in the interior of the water nanodroplets, are observed in all cases to diffuse nearby the nanodroplet surface, so that the hydrophilic heads and sodium ions become surrounded by water molecules, whereas the alkyl chains lay at the droplet surface. Meanwhile, evaporation of water molecules and of solvated sodium ions occurs, leading to a decrease of the droplet size and charge. At 350 K, no ejection of neutral or charged surfactant molecules is observed, whereas at 500 K, some fragmentation occurs, and at 800 K, this event becomes more frequent. The interplay of all these processes, which depend on the values of temperature, N(AOT)(0) and N(Na)(0) eventually leads to anhydrous charged surfactant aggregates with prevalence of monocharged ones, in agreement with experimental results of ESI mass spectrometry. The quantitative analysis of the MD trajectories allows to evidence molecular details potentially useful in designing future ESI experimental conditions.

Collisions with biomolecules embedded in small water clusters

We have studied fragmentation of water embedded adenosine 5'-monophosphate (AMP) anions after collisions with neutral sodium atoms. At a collision energy of 50 keV, loss of water molecules from the collisionally excited cluster ions is the dominant process and fragmentation of the AMP itself is almost completely prohibited if the number of attached water molecules is larger than 13. However, regardless of the initial number of water molecules attached to the ion, capture of an electron, i.e. formation of a dianion, always leads to loss of a single hydrogen atom accompanied by evaporation of water molecules. This damaging effect becomes more important as the size of the water cluster increases, which is just the opposite to the protective behavior observed for collision induced dissociation (CID) without electron transfer. For both cases, the loss of water molecules within the experimental time frame is qualitatively well described by means of a common model of an evaporative ensemble. These simulations, however, indicate that characteristically different distributions of internal energy are involved in CID and electron capture induced dissociation.