Evaporation of Ethanol and Ethanol−Water Mixtures Studied by Time-Resolved Infrared Spectroscopy

Innocenzi, Plinio; Malfatti, Luca; Costacurta, Stefano; Kidchob, Tongjit; Piccinini, M.; Marcelli, A.

doi:10.1021/jp7111395

Cited by 84 publications

(74 citation statements)

References 30 publications

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“…Changes in the alcohol evaporation rate may be induced by the adsorption of water molecules to the surface of the alcohol at high humidities. 28 The adsorption of water molecules may also occur on surface of the chloroform solution, thereby preventing the evaporation of the chloroform. To the best of our knowledge, the RH-dependent chloroform evaporation rate has not previously been investigated.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Highly Reproducible Thermocontrolled Electrospun Fiber Based Organic Photovoltaic Devices

Kim

Yang

Sung

et al. 2015

ACS Appl. Mater. Interfaces

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In this work, we examined the reasons underlying the humidity-induced morphological changes of electrospun fibers and suggest a method of controlling the electrospun fiber morphology under high humidity conditions. We fabricated OPV devices composed of electrospun fibers, and the performance of the OPV devices depends significantly on the fiber morphology. The evaporation rate of a solvent at various relative humidity was measured to investigate the effects of the relative humidity during electrospinning process. The beaded nanofiber morphology of electrospun fibers was originated due to slow solvent evaporation rate under high humidity conditions. To increase the evaporation rate under high humidity conditions, warm air was applied to the electrospinning system. The beads that would have formed on the electrospun fibers were completely avoided, and the power conversion efficiencies of OPV devices fabricated under high humidity conditions could be restored. These results highlight the simplicity and effectiveness of the proposed method for improving the reproducibility of electrospun nanofibers and performances of devices consisting of the electrospun nanofibers, regardless of the relative humidity.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Highly Reproducible Thermocontrolled Electrospun Fiber Based Organic Photovoltaic Devices

Kim

Yang

Sung

et al. 2015

ACS Appl. Mater. Interfaces

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“…For EtOH with a very low water content, water entrainment from the surrounding air may contribute. Several studies have already shown this: Innocenzi and coworkers studied the evaporation of EtOH and water from droplets by time-resolved infrared spectroscopy and found that water entrainment from the atmosphere occurred when the water content in the solution was less than 1% [48]. Katta and Chait observed water entrainment into ESI droplets in a study on H/D exchange [49].…”

Section: Mechanism Of the Solvent Polarity Changementioning

confidence: 93%

Evolution of the solvent polarity in an electrospray plume

Wang

Zenobi

2010

J. Am. Soc. Mass Spectrom.

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Solvent polarity plays an important role in electrospray ionization-mass spectrometry (ESI-MS), one of the most widely used analytical methods for biochemistry. To have a comprehensive understanding of how solvent polarity affects ESI-MS measurements, we systematically investigated the polarity change in the ESI plume formed from an ethanol solution using laser-induced fluorescence (LIF) spectroscopy. Two solvatochromic dyes (i.e., dyes whose fluorescence emission is sensitive to solvent polarity), Nile red and DCM (4-dicyanomethylene-2-methyl-6-p-dimethylaminostyryl-4H-pyran), were used as probes. The peak emission wavelengths of these two dyes exhibited significant red shifts (8 -12 nm) when the measuring spot was moved away from the spray tip and in radial direction in the plume, indicating a dramatic polarity change during shrinking of the droplets. The emission intensities were also measured with a polarity-insensitive dye as a reference. The results are consistent with the peak wavelength measurements. Two key mechanisms responsible for the change of solvent polarity in the plume were considered, water entrainment from the surrounding air and solvent evaporation. Furthermore, quantitative analysis of the solvent polarity change was performed by using the Lippert-Mataga polarity parameter ⌬f. The value of ⌬f reached 0.305-0.307 at the periphery of the ESI plume, which means that the solvent polarity in the smaller droplet is close to that of a mixture of 30% water and 70% ethanol (⌬f ϭ 0.307), even though the bulk solvent was ethanol containing less than 1% water as an impurity. (J Am Soc Mass Spectrom 2010, 21, 378 -385) © 2010 American Society for Mass Spectrometry E lectrospray ionization-mass spectrometry (ESI-MS) is widely used in many important fields, e.g., biochemistry, the food industry, and pharmacy, and is still under fast development. Despite its huge success, only relatively few fundamental studies on the mechanism of ESI have been undertaken: the different modes of the electrospray [1, 2], partitioning effects in sprayed droplets [3][4][5], size, charge, and mass changes of the droplets during solvent evaporation [6 -11], chemical equilibria in the electrospray process [12][13][14], and ion formation from the droplets [15][16][17][18][19][20] have been studied. However, more fundamental studies are still needed to make ESI-MS a totally reliable method for wider applications.In this work, we focus on one fundamental aspect of the ESI process, the solvent polarity in the ESI plume. As one of the most basic physical properties, solvent polarity controls the rates of chemical reactions [21,22] and chemical equilibria [23,24] in solution, which have been widely studied by ESI-based techniques [25][26][27]. Especially, solvent polarity can have significant effects on biomolecules. For example, the charge state of biomolecules in ESI mass spectra can vary with solvent polarity [28,29]. The solvent polarity also influences protein conformation [30], the stability of enzymes [31], and the structural ch...

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“…The same experimental technique has been applied to ethanol and water-ethanol mixtures (Innocenzi et al 2008b). The evaporation of an ethanol droplet, in particular, can be divided in different stages; the first stage of the phenomenon is dominated by the water adsorption.…”

Section: In Situ Experiments Of Evaporation Studied By Time-resolve Imentioning

confidence: 99%

Time-resolved techniques for infrared and terahertz characterization with synchrotron radiation of evaporating systems

Malfatti

Marcelli

Innocenzi

2011

Rend. Fis. Acc. Lincei

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Several time dependent phenomena are driven by evaporation processes such as the evaporation-induced self-assembly which is used to prepare mesoporous ordered films through self-organization of templating micelles. Time-resolved analytical techniques are required for following in situ changes which are triggered by solvent evaporation. Infrared and terahertz spectroscopies, in particular, can be used to set-up specific in situ and time-resolved experiments for evaporating systems. These techniques can be applied to different evaporating solutions, from simple mono-component liquids such as water and ethanol, to the multi-component precursor sols for sol-gel and mesoporous films. In this article, we show some examples of applications of time-resolved techniques based on infrared and terahertz spectroscopy using conventional and synchrotron sources to study evaporating systems.

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Evaporation of Ethanol and Ethanol−Water Mixtures Studied by Time-Resolved Infrared Spectroscopy

Cited by 84 publications

References 30 publications

Highly Reproducible Thermocontrolled Electrospun Fiber Based Organic Photovoltaic Devices

Highly Reproducible Thermocontrolled Electrospun Fiber Based Organic Photovoltaic Devices

Evolution of the solvent polarity in an electrospray plume

Time-resolved techniques for infrared and terahertz characterization with synchrotron radiation of evaporating systems

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