Polarization-modulated infrared reflection difference microspectroscopy: Experiment and model

Schmidt, Martin; Lee, J. S.; Schade, U.

doi:10.1016/j.infrared.2009.10.010

Cited by 5 publications

(5 citation statements)

References 25 publications

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“…54−56 It is responsive to alignment in dendritic fractals 39 and semicrystalline materials. 57,58 In each spectrum in Figure 5, simultaneous bright-field micrographs correspond to the colored field viewed Even though the FTIR spectrum of DBS aggregates in toluene has a broad hydroxyl stretching band (Figure 4), alignment exists clearly in a very narrow spectral region at 3475 cm −1 , corresponding to intramolecular H-bonding (Figure 5). Fiber orientation in the field of view corresponds to the sign of the dichroic difference in absorbance but does not alter the wavenumber of the anisotropic distribution of noncovalent forces.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…The measurements yield the dichroic differential absorptions, Δ A , in Figure . This technique is relatively new and, to the best of our knowledge, has not been used previously to study SAFiNs although others have exploited techniques that are sensitive to anisotropy. − It is responsive to alignment in dendritic fractals and semicrystalline materials. , In each spectrum in Figure , simultaneous bright-field micrographs correspond to the colored field viewed through a 36× objective. The spot size, 16.6 μm, was sufficiently small to allow measurements of single fibers for DBS, 6-deoxy-DBS, and 6-acetyl-DBS.…”

Section: Resultsmentioning

confidence: 99%

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Hansen Solubility Parameters Clarify the Role of the Primary and Secondary Hydroxyl Groups on the Remarkable Self-Assembly of 1:3,2:4-Dibenzylidene Sorbitol

et al. 2020

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Experimental results are reported to explain important aspects of why the classic gelator 1:3,2:4-dibenzylidene sorbitol (DBS) and five of its derivatives do or do not form gels in 23 solvents covering a wide range of properties. The conclusions from those results are based principally on changes in Hansen solubility parameters (HSPs plotted in Hansen space) and the morphologies of the self-assembled-fibrillar networks (SAFiNs). Factors in addition to H-bonding by its primary or secondary hydroxyl group are at play: although each hydroxyl group aids gelation, removal of either alters gelation ability and affects the location of dichroic absorbance differences parallel and perpendicular to the axes of fibers constituting the SAFiNs. Solvent-specific insights provide intriguing results. For 5-deoxy-DBS, for example, in toluene, removal of the secondary hydroxyl produced macroscale, spherulitic objects (comprised of highly branched nanofibers); removal of the primary hydroxyl group led to fibers that are ∼100 μm long and ∼10 μm wide. Insights into DBS self-assembly are found in quadrant analyses of the polar and hydrogen-bonding Hansen solubility parameters, which provide evidence that both the 5-OH and 6-OH groups are essential for the unique gelation ability of DBS (as defined by the broad spectrum of solvents that it gelates). Coupling the HSPs and modifications of the individual molecular synthons represents a straightforward methodology to understand the mechanisms of self-assembly. Also, measurements have been made using polarization modulation infrared linear dichroism microscopy (μPM-IRLD) to determine the anisotropy of IR absorbances at several wavelengths, including most notably those within the regions of hydroxyl, C–C, and CC stretches. The simultaneous measurement of the absorbances at two orthogonal polarization directions, A(0°) and A(90°), at the same fiber location, provides information about the orientations of the functional groups of each of the DBS derivatives relative to the fiber axes.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Hansen Solubility Parameters Clarify the Role of the Primary and Secondary Hydroxyl Groups on the Remarkable Self-Assembly of 1:3,2:4-Dibenzylidene Sorbitol

et al. 2020

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“…By coupling the PM measurements with a microscope and a synchrotron source, it is possible to obtain spatially resolved measurements of the linear dichroism with a typical spatial resolution slightly better than 10 µm . Such µPM‐IRLD measurements have been applied to a very limited number of systems to determine hydrogen bonding and orientation in wood polymer fibers, and the anisotropy of crystalline or semicrystalline domains . To the best of our knowledge, no previous studies have coupled this approach with plasmonic nanostructures.…”

Section: Resultsmentioning

confidence: 99%

Exploiting Anisotropy of Plasmonic Nanostructures with Polarization Modulation Infrared Linear Dichroism Microscopy (µPM‐IRLD)

Wallace

Read

McRae

et al. 2018

Advanced Optical Materials

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Metallic nanostructures that exhibit plasmon resonances in the mid‐infrared range are of particular interest for a variety of optical processes where the infrared excitation and/or emission can be enhanced. This plasmon‐mediated enhancement can potentially be used toward highly sensitive detection of an analyte(s) by techniques such as surface‐enhanced infrared absorption (SEIRA). To maximize the SEIRA enhancement, it is necessary to prepare highly tuned plasmonic resonances over a defined spectral range that can span over several microns. Noteworthy, nanostructures with anisotropic shapes exhibit multiple resonances that can be exploited by controlling the polarization of the input light. This study demonstrates the role of polarization‐modulation infrared linear dichroism coupled to microscopy measurements (µPM‐IRLD) as a powerful means to explore the optical properties of anisotropic nanostructures. Quantitative µPM‐IRLD measurements are conducted on a series of dendritic fractals as model structures to explore the role of structural anisotropy on the resulting surface‐enhanced infrared absorption and sensing application. Once functionalized with an analyte, the µPM‐IRLD SEIRA results highlight that it is possible to selectively enhance further vibrational modes of analytes making use of the structural anisotropy of the metallic nanostructure.

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“…During the test, the polarization-modulated infrared light was introduced to the sample surface, and the refected light was sent to the mercury cadmium telluride (MCT) detector. Finally, the fnal optical signal was processed to obtain the polarized infrared absorption spectrum of the sample [28].…”

Section: Spectral Measurement Of Samplesmentioning

confidence: 99%

Quantitative Detection of Quartz Sandstone SiO2 Grade Using Polarized Infrared Absorption Spectroscopy with Convolutional Neural Network Model

Pan

Cheng

et al. 2023

Journal of Spectroscopy

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As an independent characteristic of electromagnetic radiation, the polarization of light is sensitive to the scattering and absorption characteristics of the mineral particles. The combination of polarization and infrared absorption spectroscopy is conducive to rapidly and accurately detecting the SiO2 content of metallurgical sandstone deposits. In this study, the 8–14 μm polarized infrared absorption spectra and the grade of the sandstone ore samples were used to analyse the spectral characteristics of the sandstone powder samples. Principal component analysis (PCA) and the successive projection algorithm (SPA) were used to reduce the dimension of the original data, first-order derivative, reciprocal logarithm, and multivariate scattering correction (MSC) data. Then, generalized regression neural network (GRNN), partial least squares regression (PLSR), and convolutional neural network (CNN) were employed to establish a hyperspectral prediction model of SiO2 grade. The results show that the quantitative model by the PCA-CNN algorithm has the better prediction precision for the reciprocal logarithm data, with a coefficient of determination (R2), root mean square error (RMSE), and ratio of performance to interquartile range (RPIQ) of 0.907, 0.023, and 5.11, respectively. This method indicates that the polarized infrared absorption spectra and the PCA-CNN model can provide a more robust and significant spectral interpretation than single infrared spectra, and it is expected to be applied to any high-purity quartz deposit type for in situ and rapid analysis.

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Polarization-modulated infrared reflection difference microspectroscopy: Experiment and model

Cited by 5 publications

References 25 publications

Hansen Solubility Parameters Clarify the Role of the Primary and Secondary Hydroxyl Groups on the Remarkable Self-Assembly of 1:3,2:4-Dibenzylidene Sorbitol

Hansen Solubility Parameters Clarify the Role of the Primary and Secondary Hydroxyl Groups on the Remarkable Self-Assembly of 1:3,2:4-Dibenzylidene Sorbitol

Exploiting Anisotropy of Plasmonic Nanostructures with Polarization Modulation Infrared Linear Dichroism Microscopy (µPM‐IRLD)

Quantitative Detection of Quartz Sandstone SiO2 Grade Using Polarized Infrared Absorption Spectroscopy with Convolutional Neural Network Model

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