Microfluidics and Interfacial Chemistry in the Atmosphere

Zhang, Fei; Fu, Yao; Yu, Xiao‐Ying

doi:10.1016/b978-0-12-813641-6.00009-1

Cited by 7 publications

(7 citation statements)

References 101 publications

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“…Recently we demonstrated the feasibility of the in situ liquid SIMS to detect the a–l interfacial reactions of glyoxal and hydrogen peroxide, and this study focuses on the time effect on the a–l interfacial reactions and provides more scientific understanding and improved mechanistic information on the aqSOA formation from UV aging of glyoxal and hydrogen peroxide. Compared to the surface sensitive optical techniques such as vibrational spectroscopy including sum frequency generation (SFG) and second harmonic generation (SHG) that have been widely used in atmospheric chemistry, in situ liquid SIMS offers molecular insight complementary to chemical bond, shift, and molecular orientation information at the interface . Moreover, much larger and complicated cluster ions including water clusters can be easily observed using liquid SIMS with 2D and 3D spatial distribution.…”

Section: Resultsmentioning

confidence: 99%

“…Compared to the surface sensitive optical techniques such as vibrational spectroscopy including sum frequency generation (SFG) and second harmonic generation (SHG) that have been widely used in atmospheric chemistry, 39 in situ liquid SIMS offers molecular insight complementary to chemical bond, shift, and molecular orientation information at the interface. 40 Moreover, much larger and complicated cluster ions including water clusters can be easily observed using liquid SIMS with 2D and 3D spatial distribution.…”

Section: Resultsmentioning

confidence: 99%

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Evolution of aqSOA from the Air–Liquid Interfacial Photochemistry of Glyoxal and Hydroxyl Radicals

Zhang

Sui

et al. 2019

Environ. Sci. Technol.

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The effect of photochemical reaction time on glyoxal and hydrogen peroxide at the air−liquid (a−l) interface is investigated using in situ time-of-flight secondary ion mass spectrometry (ToF−SIMS) enabled by a system for analysis at the liquid vacuum interface (SALVI) microreactor. Carboxylic acids are formed mainly by reaction with hydroxyl radicals in the initial reactions. Oligomers, cluster ions, and water clusters formed due to longer photochemistry. Our results provide direct molecular evidence that water clusters are associated with proton transfer and the formation of oligomers and cluster ions at the a−l interface. The oligomer formation is facilitated by water cluster and cluster ion formation over time. Formation of higher m/z oligomers and cluster ions indicates the possibility of highly oxygenated organic components formation at the a−l interface. Furthermore, new chemical reaction pathways, such as surface organic cluster, hydration shell, and water cluster formation, are proposed based on SIMS spectral observations, and the existing understanding of glyoxal photochemistry is expanded. Our in situ findings verify that the a−l interfacial reactions are important pathways for aqueous secondary organic aerosol (aqSOA) formation.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Evolution of aqSOA from the Air–Liquid Interfacial Photochemistry of Glyoxal and Hydroxyl Radicals

Zhang

Sui

et al. 2019

Environ. Sci. Technol.

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“…From the result, adding SiO 2 was one way to increase the hydrophobicity of the polymer surface. It was also possible that addition of SiO 2 to the PDMS/PU blended (95:5) films would also further enhance the hydrophobic characteristics of polymer blend films, since the contact angle of water droplets on PDMS/PU blend (95:5) films in the earlier studies showed a range of WCA between 103.4° ± 3.8° to 91.4° ± 0.8° [ 12 ]. Furthermore, it is widely acknowledged that converting the hydrophobic surface of polymer film to a highly hydrophobic surface is a complex manufacturing procedure, which may involve complicated processing techniques, such as the use of plasma, etching, electrochemical reactions, decomposition etc.…”

Section: Resultsmentioning

confidence: 99%

“…The side chains of the methyl groups are hydrophobic (water contact angle (WCA) 107°–110°) and non-polar, leading to low surface energy and excellent fouling release [ 11 ]. Furthermore, because of its low shrinkage rates and ease of penetration into micropatterns, PDMS is suited for the soft lithography process [ 12 ]. The soft lithography process is a simple, cost-effective and scalable method for modifying PDMS surfaces into highly hydrophobic surfaces or superhydrophobic surfaces (WCA > 150°) with micro- and nano-patterns, or nanostructures, such as the surface of a lotus leaf, for antifouling application and corrosion resistance on metal surfaces [ 13 , 14 , 15 ].…”

Section: Introductionmentioning

confidence: 99%

Developing an Effective and Durable Film for Marine Fouling Prevention from PDMS/SiO2 and PDMS/PU with SiO2 Composites

2022

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Polymer film coating with a highly hydrophobic surface property is a practical approach to prevent fouling of any structures in the marine environment without affecting marine microorganisms. The preparation of a polymer coating, from a simple and easy method of solution blending of hydrophobic polydimethylsiloxane elastomer and hydrophilic polyurethane with SiO2, was carried out in this study, with the aim of improving characteristics, and the coating demonstrated economic feasibility for antifouling application. Incorporation of SiO2 particles into PDMS and PDMS/PU polymer film improved mechanical properties of the film and the support fabrication of micropatterns by means of a soft lithography process. Observations from field emission scanning electron microscope (FESEM) of the PDMS/SiO2 composite film revealed a homogeneous morphology and even dispersion of the SiO2 disperse phase between 1–5 wt.%. Moreover, the PDMS film with 3 wt.% loading of SiO2 considerably increased WCA to 115.7° ± 2.5° and improved mechanical properties by increasing Young’s modulus by 128%, compared with neat PDMS film. Additionally, bonding strength between barnacles and the PDMS film with 3 wt.% of SiO2 loading was 0.16 MPa, which was much lower than the bonding strength between barnacles and the reference carbon steel of 1.16 MPa. When compared to the previous study using PDMS/PU blend (95:5), the count of barnacles of PDMS with 3 wt.% SiO2 loading was lower by 77% in the two-week field tests and up to 97% in the eight-week field tests. Subsequently, when PDMS with 3 wt.% SiO2 was further blended with PU, and the surface modified by the soft lithography process, it was found that PDMS/PU (95:5) with 3 wt.% SiO2 composite film with micropatterns increased WCA to 122.1° ± 2.9° and OCA 90.8 ± 3.6°, suggesting that the PDMS/PU (95:5) with 3 wt.% SiO2 composite film with surface modified by the soft lithography process could be employed for antifouling application.

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“…The steps involve (i) designing microfluidic channels using graphic software like illustrator and AUTOCAD; (ii) transferring the design to the photomask (chrome-coated glass) and (iii) using poly(dimethylsiloxane) PDMS as elastomer microfluid chips. 64 A liquid mixture of PDMS and the cross-linking agent is discharged into the mold and vented to eliminate bubbles. Curing generally occurs at an elevated temperature of 70 1C for 12 hours utilizing a cross-linking agent as demonstrated in Fig.…”

Section: Soft Lithography Techniquesmentioning

confidence: 99%

Surface patterning techniques for proteins on nano- and micro-systems: a modulated aspect in hierarchical structures

Bhatt

Shende

2022

J. Mater. Chem. B

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Microfluidics and Interfacial Chemistry in the Atmosphere

Cited by 7 publications

References 101 publications

Evolution of aqSOA from the Air–Liquid Interfacial Photochemistry of Glyoxal and Hydroxyl Radicals

Evolution of aqSOA from the Air–Liquid Interfacial Photochemistry of Glyoxal and Hydroxyl Radicals

Developing an Effective and Durable Film for Marine Fouling Prevention from PDMS/SiO2 and PDMS/PU with SiO2 Composites

Surface patterning techniques for proteins on nano- and micro-systems: a modulated aspect in hierarchical structures

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