Evaluation of Molecular Interaction between Organic Molecules Physisorbed on Silicon Native Oxide Surface in Dry and Humid Atmosphere

Habuka, Hitoshi; Nakagomi, Ken

doi:10.1149/2.0161503jss

Cited by 4 publications

(13 citation statements)

References 15 publications

(43 reference statements)

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“…1-12 in this study and previous studies. [13][14][15][16] The A SiO2 is the unit area of the silicon oxide surface of 1 cm 2 . When the A all /A SiO2 ratio is greater than one, the organic molecules in a multi-component system were more densely arranged than those in a single-component system.…”

Section: Resultsmentioning

confidence: 99%

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In Situ Method for Determining Combination of Organic Compounds Interacting with Each Other on Silicon Oxide Surface

Choi

Habuka

2015

ECS J. Solid State Sci. Technol.

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An experimental process for determining a combination of organic compounds, interacting with each other on a silicon oxide surface, was developed using a quartz crystal microbalance. The surface concentration of the four organic compounds, such as L-menthone (Mth), decylacetate (DA), diethylphthalate (DEP) and octanol (OCT), on a silicon oxide surface was evaluated in multi-component systems. The increase and decrease in the surface concentrations were not reversible with the changing gas phase concentrations in the two-component system consisting of Mth and DEP. Additionally, the small droplet shape of Mth placed on the DEP-coated glass plate surface was significantly different from that of DEP on the Mth-coated surface. Based on these results, Mth and DEP molecules were considered to have a significant interaction with each other. In any environment for industrial production and academic research, various kinds and amounts of organic and inorganic molecules are transported and adsorbed on a material surface in a multicomponent system. The material surface condition prepared in such an environment very often governs the final product quality including various functions present on the surface. [1][2][3][4][5][6][7] In order to achieve a desirable surface condition, the adsorption behavior of various compounds should be clarified. Particularly, the combination of compounds interacting with each other should be found by means of a simple and easy method.For this purpose, the molecular behaviors in single-component and multi-component systems have been studied by taking into account the physisorption and desorption rates using the quartz crystal microbalance (QCM). 8 The information obtained by the QCM could be understood by using the Multi-Component Organic Species Adsorption-Induced Contamination (MOSAIC) model in our previous studies 9-16 using isopropanol (IPA), octanol (OCT) and diethylphthalate (DEP). In previous studies, 13-16 the molecular interaction was found to be not significant among the IPA, OCT and DEP. These studies were based on the difference in the area occupied by the organic molecule in a multi-component system from that in a singlecomponent system. In order to show the capability for finding the existence of a molecular interaction, other organic molecules having various molecular structures should be evaluated. Additionally, the process for the measurement and the analysis should be simple and easy.For this purpose, organic compounds having characteristic shapes, such as L-menthone (Mth) and decylacetate (DA), are expected. DA has an asymmetric structure consisting of a long carbon chain and oxygen. Mth also has an asymmetric shape with cyclohexane and oxygen. The oxygens in both Mth and DA are expected to have a steric hindrance when being adsorbed on the silicon oxide surface, different from IPA, OCT and DEP. Additionally, for easily finding the existence of an interaction between various compounds, a simple process should be developed; the obtained conclusions are expected to be consistent...

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Section: Resultsmentioning

confidence: 99%

“…[9][10][11][12][13][14][15][16] Assumption 1: There is quite small interaction between organic molecules in gas phase and on silicon surface. Assumption 2: Organic molecules are physisorbed on silicon surface due to very weak interactions between organic molecule and the silicon surface.…”

Section: Ecs Journal Of Solid State Science and Technology 4 (12) P4mentioning

confidence: 99%

In Situ Method for Determining Combination of Organic Compounds Interacting with Each Other on Silicon Oxide Surface

Choi

Habuka

2015

ECS J. Solid State Sci. Technol.

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“…Figure 2 shows the QCM system for in situ real-time measuring the physisorption and desorption behavior of organic compounds on a silicon surface in a dry ambient atmosphere, similar to those used in our previous studies. [10][11][12][13][14][15] The QCM sensor (AT-cut, 25 MHz, 0.5 ng cm −2 Hz −1 , Halloran Electronics Co., Ltd., Tokyo) was a quartz disc having silicon electrodes. The silicon electrode surface had a silicon native oxide film formed in ambient air.…”

Section: Methodsmentioning

confidence: 99%

“…In contrast, if the interaction was strongly attractive, the interaction may remain by the increase in the chance of molecular collisions. For this purpose, the QCM system [10][11][12][13][14][15] is expected to be applicable, because it can directly evaluate nano-gram-scale phenomena. Thus, the molecular interaction depending on the temperature should be studied using the QCM.…”

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confidence: 99%

Temperature Influence on Organic Molecular Interaction on Silicon Oxide Surface In Situ Measured Utilizing a Quartz Crystal Microbalance

Hori

Zhou

Kanai

et al. 2020

ECS J. Solid State Sci. Technol.

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The influence of temperature on the molecular interaction between diethylphthalate (DEP) and L-Menthone (Mth) on a silicon native oxide surface was in situ real time evaluated utilizing a quartz crystal microbalance. By increasing the temperature from 25 °C to 35 °C in a single component system, the physisorption and desorption rate constants of DEP increased, while those of Mth showed significantly small changes. Simultaneously, the surface concentrations of DEP and Mth decreased with the increasing temperatures. In the two-component system, the surface concentration was measured by alternatively changing gas phase concentrations of DEP and Mth in order to evaluate whether it irreversibly or reversibly changed. Because the surface concentration change was irreversible at 25 °C, the molecular interaction between the DEP and Mth was considered to exist. In contrast, the change became reversible with the increasing temperature to produce a negligible molecular interaction between them. Such a behavior change occurred in the temperature range less than 10 °C. The low surface concentration by the increasing temperature was considered to weaken the attractive molecular interaction.

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“…Humidified gas can be employed during the drying of active pharmaceutical ingredients (APIs) when it is necessary to preserve the product as a desired crystalline hydrate or to favorably impact the drying kinetics for the removal of processing solvents. − The process is internally referred to as “humid drying” if the water content of the drying gas is maintained above a critical relative humidity (i.e., water activity) such that the hydrated form is isolated successfully while excess water and other processing solvents are removed to desired levels.…”

Section: Introductionmentioning

confidence: 99%

Robust Process Scale-Up Leveraging Design of Experiments to Map Active Pharmaceutical Ingredient Humid Drying Parameter Space

Lamberto

Neuhaus²

2021

Org. Process Res. Dev.

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Sugammadex is a modified γ-cyclodextrin active pharmaceutical ingredient (API) that is used as a reversal agent for neuromuscular blockade drugs in general anesthesia. The open structure of the cyclodextrin molecule yields a multitude of solid forms, and to date, more than 12 different mixed methanol solvate/hydrate forms have been characterized. Historically, the kinetic form (type 1) was manufactured to ensure that the solids could be dried successfully using only heat and vacuum to meet the specifications for residual solvents. Isolation of the thermodynamic form (type 2) was avoided due to the inability to remove process solvents to desired levels during drying and the subsequent need to rework the solids. To meet increasing product demand through improved robustness, the process was redesigned to manufacture the thermodynamic form (type 2). Therefore, an improved drying process had to be developed to enable meeting residual solvent levels of the final API at a large scale. Small-scale drying experiments were performed using a custom, in-house, process analytical technology-enabled drying platform to visualize the real-time evolution of the process solvents and water from the solids and to monitor form change. The mechanism for solvent removal in this case was found to be unique since it was independent of API crystallinity. The key element for successful drying was the displacement of solvent by water molecules, regardless of whether the crystal structure remained intact or collapsed. A predictive model was developed through design of experiments including three-factor interactions of drying humidity, temperature, and pressure, and the model was used to define the operating space to ensure successful drying. The humid drying conditions identified in this study were implemented across scales to ensure that residual solvent specifications were achieved regardless of the crystalline form generated.

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Evaluation of Molecular Interaction between Organic Molecules Physisorbed on Silicon Native Oxide Surface in Dry and Humid Atmosphere

Cited by 4 publications

References 15 publications

In Situ Method for Determining Combination of Organic Compounds Interacting with Each Other on Silicon Oxide Surface

In Situ Method for Determining Combination of Organic Compounds Interacting with Each Other on Silicon Oxide Surface

Temperature Influence on Organic Molecular Interaction on Silicon Oxide Surface In Situ Measured Utilizing a Quartz Crystal Microbalance

Robust Process Scale-Up Leveraging Design of Experiments to Map Active Pharmaceutical Ingredient Humid Drying Parameter Space

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