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Tangeysh B, Palmer C, Metiu H, Gordon MJ, McFarland EW. High-temperature heterogeneous catalysis in platinum nanoparticle – molten salt suspensions. Catal Sci Technol 2020. [DOI: 10.1039/c9cy01823a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Suspensions of platinum nanoparticles (PtNPs) were formed in molten LiCl–LiBr–KBr via thermal decomposition of H2PtCl6, and subsequently evaluated for thermal stability and CO oxidation activity.
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Affiliation(s)
- Behzad Tangeysh
- Department of Chemical Engineering
- University of California
- Santa Barbara
- USA
| | - Clarke Palmer
- Department of Chemical Engineering
- University of California
- Santa Barbara
- USA
| | - Horia Metiu
- Department of Chemistry and Biochemistry
- University of California
- Santa Barbara
- USA
| | - Michael J. Gordon
- Department of Chemical Engineering
- University of California
- Santa Barbara
- USA
| | - Eric W. McFarland
- Department of Chemical Engineering
- University of California
- Santa Barbara
- USA
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4
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Carrascal JJ, Villegas JM, Baena-Aristizábal CM, Baena Y, Perez LD. Nanoparticles based on a PEGylated methacrylate copolymer as vehicles for hydrophilic antimicrobial additives: a study on chemical interactions with a benzoic acid probe molecule. Colloid Polym Sci 2019. [DOI: 10.1007/s00396-019-04502-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Thomas M, Gajda M, Amiri Naini C, Franzka S, Ulbricht M, Hartmann N. Poly(N,N-dimethylaminoethyl methacrylate) Brushes: pH-Dependent Switching Kinetics of a Surface-Grafted Thermoresponsive Polyelectrolyte. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:13426-13432. [PMID: 26569145 DOI: 10.1021/acs.langmuir.5b03448] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The temperature-dependent switching behavior of poly(N,N-dimethylaminoethyl methacrylate) brushes in alkaline, neutral, and acidic solutions is examined. A novel microscopic laser temperature-jump technique is employed in order to study characteristic thermodynamic and kinetic parameters. Static laser micromanipulation experiments allow one to determine the temperature-dependent variation of the swelling ratio. The data reveal a strong shift of the volume phase transition of the polymer brushes to higher temperatures when going from pH = 10 to pH = 4. Dynamic laser micromanipulation experiments offer a temporal resolution on a submillisecond time scale and provide a means to determine the intrinsic rate constants. Both the swelling and the deswelling rates strongly decrease in acidic solutions. Complementary experiments using in situ atomic force microscopy show an increased polymer layer thickness at these conditions. The data are discussed on the basis of pH-dependent structural changes of the polymer brushes including protonation of the amine groups and conformational rearrangements. Generally, repulsive electrostatic interactions and steric effects are assumed to hamper and slow down temperature-induced switching in acidic solutions. This imposes significant restrictions for smart polymer surfaces, sensors, and devices requiring fast response times.
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Affiliation(s)
- Marc Thomas
- Physical Chemistry, Department of Chemistry, and ‡Technical Chemistry II, Department of Chemistry, University of Duisburg-Essen , 45117, Essen, Germany
- Center for Nanointegration Duisburg-Essen (CENIDE) and ∥Interdisciplinary Center for Analytics on the Nanoscale (ICAN), University of Duisburg-Essen , 47057 Duisburg, Germany
| | - Martyna Gajda
- Physical Chemistry, Department of Chemistry, and ‡Technical Chemistry II, Department of Chemistry, University of Duisburg-Essen , 45117, Essen, Germany
- Center for Nanointegration Duisburg-Essen (CENIDE) and ∥Interdisciplinary Center for Analytics on the Nanoscale (ICAN), University of Duisburg-Essen , 47057 Duisburg, Germany
| | - Crispin Amiri Naini
- Physical Chemistry, Department of Chemistry, and ‡Technical Chemistry II, Department of Chemistry, University of Duisburg-Essen , 45117, Essen, Germany
- Center for Nanointegration Duisburg-Essen (CENIDE) and ∥Interdisciplinary Center for Analytics on the Nanoscale (ICAN), University of Duisburg-Essen , 47057 Duisburg, Germany
| | - Steffen Franzka
- Physical Chemistry, Department of Chemistry, and ‡Technical Chemistry II, Department of Chemistry, University of Duisburg-Essen , 45117, Essen, Germany
- Center for Nanointegration Duisburg-Essen (CENIDE) and ∥Interdisciplinary Center for Analytics on the Nanoscale (ICAN), University of Duisburg-Essen , 47057 Duisburg, Germany
| | - Mathias Ulbricht
- Physical Chemistry, Department of Chemistry, and ‡Technical Chemistry II, Department of Chemistry, University of Duisburg-Essen , 45117, Essen, Germany
- Center for Nanointegration Duisburg-Essen (CENIDE) and ∥Interdisciplinary Center for Analytics on the Nanoscale (ICAN), University of Duisburg-Essen , 47057 Duisburg, Germany
| | - Nils Hartmann
- Physical Chemistry, Department of Chemistry, and ‡Technical Chemistry II, Department of Chemistry, University of Duisburg-Essen , 45117, Essen, Germany
- Center for Nanointegration Duisburg-Essen (CENIDE) and ∥Interdisciplinary Center for Analytics on the Nanoscale (ICAN), University of Duisburg-Essen , 47057 Duisburg, Germany
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6
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Min SH, Kwak SK, Kim BS. Atomistic simulation for coil-to-globule transition of poly(2-dimethylaminoethyl methacrylate). SOFT MATTER 2015; 11:2423-2433. [PMID: 25662300 DOI: 10.1039/c4sm02242d] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The coil-to-globule transition of poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) in aqueous solution was investigated by all-atomistic molecular dynamics simulations. The polymer consistent force field (PCFF) was applied to the PDMAEMA model with a proper protonation state. The structural analysis indicates a distinct difference in the hydration state of particular functional groups of PDMAEMA as well as in the conformational state of PDMAEMA below and above the lower critical solution temperature (LCST). In particular, by monitoring the motion of water molecules, we observe that water molecules in the vicinity of the carbonyl group are relatively restricted to the motion in the globule state due to the extended relaxation time of hydrogen bonds among water molecules. The degree of protonation was also adjusted to study the effect of protonation on the conformational state of PDMAEMA.
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Affiliation(s)
- Sa Hoon Min
- Department of Energy Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Korea
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Ye Z, Tangeysh B, Wayland BB. Metal dication cross-linked polymer network colloids as an approach to form and stabilize unusually small metal nanoparticles. Chem Commun (Camb) 2013; 49:5372-4. [DOI: 10.1039/c3cc41778f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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