Giant surface potentials (GSPs) generated by spontaneous orientation polarization in vacuum-deposited organic films have attracted considerable attention for applications such as vibrational energy harvesting. However, their stability under humid conditions remains poorly understood. In this study, we systematically investigate the humidity-dependent degradation of GSPs using two representative materials with contrasting electrical properties: insulating a perfluoro-adamantane derivative (PTAA) and more conductive diarylethene derivative (DAE1). While PTAA exhibits excellent stability, DAE1 shows significant potential decay under humid conditions.

It is well known that vacuum deposition of organic molecules possessing electric dipoles leads to spontaneous molecular orientation, resulting in the formation of a giant surface potential (GSP). The GSP is expected to be useful for energy-harvesting devices, and improving carrier injection in organic light-emitting diodes; therefore, maximizing the GSP is crucial for device performance. Here, we systematically investigate the factors governing GSP formation by examining the roles of glass transition temperature (Tg), substrate temperature (Tsub), and deposition rate using a series of organic materials, including adamantane derivatives, diarylethenes, and spiropyrans. The molecular orientation parameter < cos theta > exhibits a clear dependence on Tg, indicating that surface molecular dynamics during deposition play a dominant role. We demonstrate that the GSP slope is maximized when Tsub is maintained at approximately 0.8-0.85 Tg. This condition coincides with the maximum enthalpy relaxation of vapor-deposited organic glasses. Based on these results, we propose a three-regime model describing GSP generation as a function of surface molecular mobility (Tsub/Tg scaling), providing practical guidelines for maximizing GSP in vapor-deposited organic thin films.

Photoisomerization-induced solubility change of a photochromic diarylethene (DAE) derivative is investigated by a combination of theoretical calculations and experimental measurements. A significant solubility change is experimentally observed between two DAE photoisomers (open and closed forms) in n-octane solution. To elucidate the reason for the observed solubility change, we adopt a thermodynamic model and consider both ideal and nonideal contributions. The analysis revealed that both the crystalline stability of the isomers and their solute-solvent interactions play critical roles in determining the solubility difference. We believe that the current elucidation of thermodynamic properties will be useful to develop new functions of the DAE derivatives and future applications.

Vacuum-deposited organic molecular films can generate giant surface potentials (GSPs) through spontaneous molecular orientation. Here we show that these GSPs can directly drive autonomous water droplet motion via dielectrophoretic forces, enabling high-speed transport of up to ∼15 cm s-1 without electrodes or externally introduced charges. The motion originates from an electric field gradient formed between the GSP region and the potential-relaxed area beneath the droplet. Using photopatterning of photochromic diarylethene, droplet trajectories can be spatially programmed. We further demonstrate that the long-standing issue of GSP photostability can be overcome using highly insulating molecular materials. This GSP-driven mechanism provides a new strategy for electrode-free droplet manipulation and opens opportunities in microfluidics, diagnostics, chemical synthesis, and energy harvesting.

Controlling droplet motion on solid surfaces presents significant challenges in chemistry, physics, and materials science, especially for potential applications in "lab-on-a-chip" technologies. Traditional methods, such as using electric fields produced by electrodes, often inadequately manage complex droplet motion. Here we show a novel approach utilizing giant surface potentials (GSPs) generated through customizable photopatterning during vacuum deposition. Water droplets move spontaneously due to the potential difference between the GSP surface and the surface where the droplet comes into contact, which has a reduced potential. Our study not only enhances droplet control but also improves the photostability of the surface potential. We identify the optimal conditions for GSP generation, achieved under vacuum-deposition conditions conducive to maximum enthalpy relaxation, and demonstrate its potential for creating customizable, complex droplet flow channels. These advances offer significant promise for microfluidic devices, medical diagnostics, chemical synthesis, and energy harvesting applications.

The prediction of odor characters is still impossible based on the odorant molecular structure. We designed a CNN-based regressor for computed parameters in molecular vibrations (CNN_vib), in order to investigate the ability to predict odor characters of molecular vibrations. In this study, we explored following three approaches for the predictability; (i) CNN with molecular vibrational parameters, (ii) logistic regression based on vibrational spectra, and (iii) logistic regression with molecular fingerprint(FP). Our investigation demonstrates that both (i) and (ii) provide predictablity, and also that the vibrations as an explanatory variable (i and ii) and logistic regression with fingerprints (iii) show nearly identical tendencies. The predictabilities of (i) and (ii), depending on odor descriptors, are comparable to those of (iii). Our research shows that odor is predictable by odorant molecular vibration as well as their shapes alone. Our findings provide insight into the representation of molecular motional features beyond molecular structures.

Odor is analyzed on the human olfactometry systems in various steps. The mapping from chemical structures to olfactory perceptions of smell is an extremely challenging task. Scientists have been unable to find a measure to distinguish the perceptual similarity between odorants. In this study, we report regression analysis and visualization based on the odorant chemical space. We discuss the relation between the odor descriptors and their structural diversity for odorants groups associated with each odor descriptor. We studied the influence of structural diversity on the odor descriptor predictability. The results suggest that the diversity of molecular structures, which is associated with the same odor descriptor, is related to the resolutional confusion with the odor descriptor.

It is widely accepted that the gamma relaxation of poly(methyl methacrylate) (PMMA) arises from the hindered rotational motion of the side chain around the C-C bond, which links to the main chain. However, the physical model to explain this process has been unknown. The hybrid density functional theory calculation showed that the PMMA intramolecular hindered rotation has an activation energy of 6.53 kcal/mol. This activation energy causes the friction coefficient to the intramolecule to hinder rotation. The qualitative value of the friction coefficient was evaluated on the basis of linear response theory by using the calculated value of the activation energy. The Lorentz model is adopted to calculate the complex dielectric constant of the gamma relaxation using the calculated value of the friction coefficient. The calculated value of the complex dielectric constant agreed reasonably well with experimental results.

The air-nasal mucus partition coefficient is a crucial property among all of the interaction mechanisms between odor molecules and olfactory receptors, since this property contributes to our sense of smell. Due to the complexity of the mucus composition, in vivo determination of the air-mucus partition coefficient is a technical challenge. A predictable model of the air-mucus partition coefficient can provide valuable insights into the chemical properties that govern olfactory perception and can help design desired odorants. In this study, we propose a novel model based on the deep-layer neural network (DNN) algorithm to predict the air-mucus partition coefficients for a range of odor compounds. The molecular surface charge density (σ-profile) calculated from the COnductor like Screening MOdel for Real Solvents (COSMO-RS) thermodynamic package was adapted as descriptors of structural features of odor molecules. The results revealed that the air-mucus partition coefficients are highly correlated to the σ-profile of the studied compounds. The information obtained from the study provided interpretable results, which not only help in identifying the molecular features that contribute to the air-mucus partition coefficient of odorants but also aid in the design of compounds with the desired odor properties.

The rate of the Rubisco carboxylase reaction is evaluated by statistical mechanics and hybrid density functional theory (DFT). The Rubisco molecular model given by Kannappan et al. was modified and used in the present calculation. The activation energies of CO2 addition reaction, H2O addition reaction, C2-C3 bond scission, and C2 protonation are estimated. We calculated the turnover number (TON) for each of the four reaction steps based on a revised absolute reaction rate theory, which became applicable to soft matter reactions. The molecular parameters used in TON calculations were obtained by DFT calculations. The TON of the total Rubisco reaction was finally evaluated using rate equations. The calculation in a vacuum gave the total TON to be around 5 × 10-5, which was much lower than the experimental value. The DFT calculation in water solvent gave the total TON to be around 0.1, which agreed reasonably well with experimentally reported values (∼2.71). The rate-limiting process was the scission reaction. The present calculation showed that both the phosphate groups in the substrate accelerate each reaction step. The present calculation showed that a more comprehensive molecular model including enolization and quantum chemical methods is necessary to make a more precise reaction model including the irreversibility of some reactions.

To understand the porous polymer films' mechanical behavior from the perspective of their structural features, a three-dimensional (3D) reconstruction based on the focused ion beam/scanning electron microscope images was applied to obtain the microstructural information for two samples with distinct structures. With accurate image-based 3D models, the finite element analysis was carried out to investigate the effects of film microstructure on the mechanical properties under uniaxial tensile loading. Good agreement is found by comparing the modeling and simulation results with the experimentally measured stress-strain data from tensile tests. Insights from mechanical simulation incorporated with 3D microstructure characterization can help guide the development of porous polymer films with high strength and toughness.

Development of coke production technology which can maintain high coke strength with use of certain amount of high rank coal is needed. Accordingly, it is important to investigate influence of coke pore structure on coke strength and dominant factors of coke strength. In this study, results of three-dimensional analysis such as components of coke structure and Mises stress of two types of high strength coke will be presented. Three-dimensional composition of coke was successfully visualized and quantified by three-valuation method. Moreover, three-dimensional stress analysis was conducted to investigate the relationship between coke structure and coke strength.

Focused ion beam / scanning electron microscope (FIB/SEM) technique is a powerful approach for three-dimensional (3D) structural analysis at the submicron scale. However there are only a limited number of studies on the application of FIB/SEM tomography to quantify microstructural characteristics of porous polymer materials. In order to gain insight into the relationship between the mechanical properties and the features of 3D interconnected porous micro-structure, the 3D micro-structure of porous polymer was reconstructed based on the as-recorded stacks of FIB/SEM images, and then the mechanical properties were calculated by finite element modelling (FEM) using the reconstructed 3D model. A series of the high resolution, high contrast In-Lens-SEM images (Fig. 1 (a)) was generated by FIB/SEM instrument (Helios dual-beam, FEI). Fig. 1 (b) shows the 3D volume of a part of the porous polymer reconstructed based on the stacks of FIB/SEM images, the internal shape and their connectivity of pores in the model could be visualized very distinctly. Moreover, the mechanical properties from the numerical simulation based on the reconstructed 3D model show a good agreement with those observed by experiments. As a result, a combined FIB/SEM tomography and FEM study could help to in-depth understand microstructural features of porous polymer by taking into account mechanical performance.

Molecular dynamics (MD) simulations were used to investigate the dissociation of the Ras/Raf complex. Three models of Ras/Raf complexes were used in this study: two active GTP-bound forms with eith...

The 1,2,4-triazole moiety is associated with diverse pharmacological activities, such as antibacterial, antifungal, antiviral, antiinflammatory, anticonvulsant, antidepressant, antihypertensive, analgesic, and hypoglycemic properties [1].Furthermore, some of the complexes containing 1,2,4-triazole ligands have rather peculiar structures and specific magnetic properties [2].The experimental geometry obtained from single-crystal Xray diffraction was compared with those obtained from quantummechanical calculations in the gas phase and in solution phase.In addition, proton transfer reactions and hydrogen bonding interactions have been studied.The solvent effect has been investigated by Polarizable Continuum Model (PCM) [3] method using three kinds of solvent (chloroform, methanol and water).Thoretical calculations were performed by means of GAUSSIAN 03W [4] at the density functional theory (DFT/B3LYP) [5,6] level using the 6-311++G(d,p) basis set [7,8].

The grain morphology of tetrabenzoporphyrin (TBP) after solid-state crystallization by annealing from tetrabicycloporphyrin (CP) was found to be influenced by the annealing temperature, but the grain orientation was not significantly changed by the temperature. From the thin film XRD measurements, the b axis, which is the most favorite direction to enhance the carrier mobility, was found to grow in parallel to the substrate, but at high temperatures, the growth direction was slightly inclined from the substrate surface. The FET performance showed dependency on the annealing temperatures, showing that the carrier mobility was three times higher for the film prepared at lower temperature compared to that at higher temperatures.

Pigment Yellow 181 is an industrially important reddish yellow pigment.The pigment usually crystallizes in thin needles.With a special additive a plate-like morphology can be obtained.［1］ The platelets are arranged into a porous microsphere structure.Molecular modelling was used to study the influence of the additive on the pigment morphology.The adsorption enthalpies of a fragment of the additive on several crystal faces were calculated.The calculations show that the additive adsorbs preferably on one face and also blocks the growth in the needle direction.In consequence the pigment crystallizes not in thin needles but in plates.

Alkylketene dimer (AKD: a kind of wax) spontaneously forms a fractal structure and its surfaces show super water-repellency (the contact angle = 174°). However, the formation mechanism of the fractal surfaces of AKD is still unclear. In this work, surface structures, wettability and phase behaviors of various waxes have been investigated in order to understand the mechanism for spontaneous formation of super water-repellent fractal surfaces. We have found an empirical general rule without any exceptions at least for the wax samples tested. First, the wax must form a meta-stable crystalline phase when solidified from its melt. Then, the super water-repellent fractal surfaces form spontaneously during the phase transition from a meta-stable to a stable crystalline form. The tempering method also supported the above rule for the waxes showing the fractal structure formation on their surfaces.