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Sum frequency generation imaging for semi-crystalline polymers. Polym J 2022. [DOI: 10.1038/s41428-021-00613-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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2
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Shah S, Baldelli S. Vibrational Ground-State depletion for enhanced resolution sum frequency generation microscopy. Chem Phys Lett 2022. [DOI: 10.1016/j.cplett.2021.139252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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3
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Wang H, Xiong W. Vibrational Sum-Frequency Generation Hyperspectral Microscopy for Molecular Self-Assembled Systems. Annu Rev Phys Chem 2021; 72:279-306. [PMID: 33441031 DOI: 10.1146/annurev-physchem-090519-050510] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In this review, we discuss the recent developments and applications of vibrational sum-frequency generation (VSFG) microscopy. This hyperspectral imaging technique can resolve systems without inversion symmetry, such as surfaces, interfaces and noncentrosymmetric self-assembled materials, in the spatial, temporal, and spectral domains. We discuss two common VSFG microscopy geometries: wide-field and confocal point-scanning. We then introduce the principle of VSFG and the relationships between hyperspectral imaging with traditional spectroscopy, microscopy, and time-resolved measurements. We further highlight crucial applications of VSFG microscopy in self-assembled monolayers, cellulose in plants, collagen fibers, and lattice self-assembled biomimetic materials. In these systems, VSFG microscopy reveals relationships between physical properties that would otherwise be hidden without being spectrally, spatially, and temporally resolved. Lastly, we discuss the recent development of ultrafast transient VSFG microscopy, which can spatially measure the ultrafast vibrational dynamics of self-assembled materials. The review ends with an outlook on the technical challenges of and scientific potential for VSFG microscopy.
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Affiliation(s)
- Haoyuan Wang
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA; ,
| | - Wei Xiong
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA; , .,Materials Science and Engineering Program, University of California, San Diego, La Jolla, California 92093, USA
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Li H, Kelly KF, Baldelli S. Spectroscopic imaging of surfaces-Sum frequency generation microscopy (SFGM) combined with compressive sensing (CS) technique. J Chem Phys 2020; 153:190901. [PMID: 33218244 DOI: 10.1063/5.0022691] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Surface chemistry is notoriously difficult to study, in part, due to the decreased number of molecules that contribute to the properties compared to the bulk phase but often has significant effects on the chemical activity of the material. This is especially true in topics such as corrosion, catalysis, wetting, and many others in nature and industry. Sum frequency generation (SFG) spectroscopy was developed for interface studies due to its high molecular selectivity and surface sensitivity, which is quite useful to study the effects of structural inhomogeneity in microscopy. Compressive sensing (CS) combined with SFG spectroscopy minimizes the imaging time while still producing quality images. Selected systems are presented here to demonstrate the capability of CS-SFG microscopy. CS-SFG microscopy successfully distinguished the static monolayer molecular mixtures, the orientations and adsorption of adsorbed molecules by the dip-coating technique, and the localized CO behaviors on polycrystalline Pt electrodes. Further discussion includes dynamic imaging as a future direction in CS-SFG microscopy. As materials and surfaces become more complex, imaging with chemical contrast becomes indispensable to understanding their performance and CS-SFG microscopy seems highly beneficial in this respect.
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Affiliation(s)
- Hao Li
- Department of Chemistry, University of Houston, Houston, Texas 77204-5003, USA
| | - Kevin F Kelly
- Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, USA
| | - Steven Baldelli
- Department of Chemistry, University of Houston, Houston, Texas 77204-5003, USA
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Shah SA, Baldelli S. Chemical Imaging of Surfaces with Sum Frequency Generation Vibrational Spectroscopy. Acc Chem Res 2020; 53:1139-1150. [PMID: 32437170 DOI: 10.1021/acs.accounts.0c00057] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Surface chemistry is a key area of study in the chemical sciences, and many system properties are dominated by the chemistry at the interface between two bulk media. While the interface may have a large influence on the system behavior, there are relatively few molecules at the interface compared to the bulk; thus, probing their unique properties has become a specialized field in physical chemistry. In addition to the heterogeneous phase chemistry, surfaces also present spatial heterogeneity (Chemistry in Two Dimensions). This 2D chemistry affects the properties as much as the heterogeneous phases. If we consider the Cartesian z-axis as defining the dimension across the interface between the two bulk phases, then the x-y plane is the 2D region of the surface. We might even consider that the majority of surface chemistry has been concerned with this z-dimension, i.e., surface structure, partition excess, thermodynamics, etc. relative to the bulk, where the 2D distribution was only considered on average. This treatment is understandable since few techniques provide the spatial and chemical resolution needed to deduce the effects of 2D heterogeneity on the surface properties. It is desirable to use an all-optical technique for interface studies because the optical methods provide the chemical specificity through spectroscopy. Also, the use of second-order spectroscopy is typically surface-sensitive without background subtractions or enhancement mechanisms that could limit the range of systems to be investigated.In this Account, the development and selected results of sum frequency generation microscopy and its contributions to the surface chemistry are presented. Sum frequency generation (SFG) provides a unique probe for studying surface chemistry in ambient conditions with surface specificity. SFG provides image contrast based on multiple-chemically important-mechanisms such as chemical functional groups, molecular orientation, surface concentration, molecular conformation, local electric fields, among others. To understand the spatial distribution of heterogeneous chemistry, multiple microscopy methods have been developed which utilize the SFG process to yield spatial information with chemical sensitivity. These spectroscopic-microscopies come with unique advantages as well as challenges. Multiple solutions have been developed in this field to overcome the challenges and improve the advantages. In this Account, some of the leading SFG surface microscopies for surface studies are introduced. Initially, direct imaging of the SFG signal onto a CCD camera provided spatially and spectrally resolved imaging of monolayers on surfaces. However, to speed up the imaging process, the technique of compressive sensing was applied to SFG imaging. Most recently the use of machine learning methods and target factor analysis have improved the quality and acquisition speed of SFG images.
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Affiliation(s)
- Syed Alamdar Shah
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
| | - Steven Baldelli
- Department of Chemistry, University of Houston, Houston, Texas 77204, United States
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Zhu X, Jia X, Zhang Y, Luo Y, Bo H. Synthesis and Characterization of a Novel Short Fluorocarbon Chain Cationic Surfactant. J SURFACTANTS DETERG 2020. [DOI: 10.1002/jsde.12425] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Xinhua Zhu
- College of Civil Aviation Safety EngineeringCivil Aviation Flight University of China Guanghan 618307 People's Republic of China
| | - Xuhong Jia
- College of Civil Aviation Safety EngineeringCivil Aviation Flight University of China Guanghan 618307 People's Republic of China
| | - Yuqiang Zhang
- College of Civil Aviation Safety EngineeringCivil Aviation Flight University of China Guanghan 618307 People's Republic of China
| | - Yuzhen Luo
- College of Civil Aviation Safety EngineeringCivil Aviation Flight University of China Guanghan 618307 People's Republic of China
| | - Haidong Bo
- College of Civil Aviation Safety EngineeringCivil Aviation Flight University of China Guanghan 618307 People's Republic of China
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Pikalov AA, Ngo D, Lee HJ, Lee TR, Baldelli S. Sum Frequency Generation Imaging Microscopy of Self-Assembled Monolayers on Metal Surfaces: Factor Analysis of Mixed Monolayers. Anal Chem 2019; 91:1269-1276. [PMID: 30605304 DOI: 10.1021/acs.analchem.8b01840] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Sum frequency generation (SFG) images of microcontact patterned self-assembled alkanethiol monolayers on metal surfaces were analyzed by factor analysis (FA) to determine the spatial distribution of the patterned monolayers over the images. Additionally, each significant abstract factor produced by FA was assessed to determine the information contained within it. These results indicate that FA of the SFG spectra is a promising method to determine the composition and identities of mixed alkanethiol systems that show different vibrational spectra and image contrast. Factor analysis has successfully been applied to SFG images obtained with low signals, which reduces the time required for full spectral SFG imaging.
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Affiliation(s)
- Aleksandr A Pikalov
- Department of Chemistry , University of Houston , Houston , Texas 77204-5003 , United States
| | - Dien Ngo
- Department of Chemistry , University of Houston , Houston , Texas 77204-5003 , United States
| | - Han Ju Lee
- Department of Chemistry , University of Houston , Houston , Texas 77204-5003 , United States
| | - T Randall Lee
- Department of Chemistry , University of Houston , Houston , Texas 77204-5003 , United States
| | - Steven Baldelli
- Department of Chemistry , University of Houston , Houston , Texas 77204-5003 , United States
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Adsorption, aggregation and wetting behaviors of biodegradable surfactant: Perfluoropolyether quaternary ammonium salt. J IND ENG CHEM 2017. [DOI: 10.1016/j.jiec.2017.06.048] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Zheng D, Lu L, Kelly KF, Baldelli S. Chemical Imaging of Self-Assembled Monolayers on Copper Using Compressive Hyperspectral Sum Frequency Generation Microscopy. J Phys Chem B 2017; 122:464-471. [PMID: 28795555 DOI: 10.1021/acs.jpcb.7b03339] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Sum frequency generation microscopy is a label-free optical imaging technique with intrinsic molecular vibrational contrast for surface studies. Recent developments of compressive sensing broad-band hyperspectral SFG microscopy have demonstrated the potential application for imaging monolayer at metal surfaces with micrometer spatial resolution. Here is presented the capability of chemical imaging of spatially patterned monolayers of 1-octadecanethiol (ODT) and 16-methoxy-1-hexadecanethiol (MeOHT) molecules assembled on a copper surface. The spatial distributions of the monolayer with vibrational-spectral contrast are well-demonstrated at different frequency regions through reconstruction of the hypercube using a 3-dimensional total variation regularization algorithm (3DTV). Spatial-chemical distributions of each component are also reconstructed directly from the compressive measurements by endmember unmixing (CEU) scheme. Compared to 3DTV algorithm, the reconstruction from CEU shows spatial distribution of each component on the surfaces, and demonstrates the ability to characterize the domains of mixed-molecules on surfaces.
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Affiliation(s)
- Desheng Zheng
- Department of Chemistry, University of Houston , Houston, Texas 77204-5003, United States
| | - Liyang Lu
- Department of Electrical and Computer Engineering, Rice University , Houston, Texas 77005, United States
| | - Kevin F Kelly
- Department of Electrical and Computer Engineering, Rice University , Houston, Texas 77005, United States
| | - Steven Baldelli
- Department of Chemistry, University of Houston , Houston, Texas 77204-5003, United States
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Donovan MA, Lutz H, Yimer YY, Pfaendtner J, Bonn M, Weidner T. LK peptide side chain dynamics at interfaces are independent of secondary structure. Phys Chem Chem Phys 2017; 19:28507-28511. [DOI: 10.1039/c7cp05897g] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Real-time observation of the ultrafast motions of leucine side chains within model peptides at the water–air interface with representative folds – α-helix, 310-helix, β-strand – show that interfacial dynamics are mostly determined by surface interactions.
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Affiliation(s)
| | - Helmut Lutz
- Max Planck Institute for Polymer Research
- 55128 Mainz
- Germany
| | - Yeneneh Y. Yimer
- Department of Chemical Engineering
- University of Washington
- 105 Benson Hall
- Seattle
- USA
| | - Jim Pfaendtner
- Department of Chemical Engineering
- University of Washington
- 105 Benson Hall
- Seattle
- USA
| | - Mischa Bonn
- Max Planck Institute for Polymer Research
- 55128 Mainz
- Germany
| | - Tobias Weidner
- Max Planck Institute for Polymer Research
- 55128 Mainz
- Germany
- Department of Chemical Engineering
- University of Washington
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