scholarly journals The Multilevel Structure of Sulfonated Syndiotactic-Polystyrene Model Polyelectrolyte Membranes Resolved by Extended Q-range Contrast Variation SANS

2019 ◽  
Author(s):  
Maria-Maddalena Schiavone ◽  
Hiroki Iwase ◽  
Shin-ichi Takata ◽  
Aurel Radulescu
Keyword(s):  
Solid State ◽  
Syndiotactic Polystyrene ◽  
Contrast Variation ◽  
Guest Molecules ◽  
Multilevel Structure ◽  
Membrane Morphology ◽  
Polyelectrolyte Membranes ◽  
Structural Levels ◽  
Identification And Characterization

Membranes based on sulfonated synditoactic polystyrene were thoroughly characterized by contrast variation SANS over a wide Q-range in dry and hydrated states. The film samples were prepared by solid-state sulfonation that allowed a uniform sulfonation of only the amorphous phase while preserving the crystallinity of the membrane. The samples were loaded with different guest molecules in either the amorphous (fullerenes) or the crystalline (toluene) regions, in order to vary the neutron contrast or to reproduce the conditions enabling an increased resistance of the membranes to chemical decomposition. The use of uni-axially deformed film samples and contrast variation with different H2O/D2O mixtures allowed for the identification and characterization of different structural levels with sizes between nm and μm, which form and evolve in the membrane morphology in dry and hydrated states and produce scattering features on different detection sectors and at different detection distances after the sample, depending on their size and orientation.

scholarly journals The Multilevel Structure of Sulfonated Syndiotactic-Polystyrene Model Polyelectrolyte Membranes Resolved by Extended Q-Range Contrast Variation SANS

Membranes ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 136 ◽  
Author(s):  
Maria-Maddalena Schiavone ◽  
Hiroki Iwase ◽  
Shin-ichi Takata ◽  
Aurel Radulescu
Keyword(s):  
Scattering Length ◽  
Contrast Variation ◽  
Multilevel Structure ◽  
Polyelectrolyte Membranes ◽  
Resistance To Oxidation ◽  
Formation And Evolution ◽  
Treatment Procedures ◽  
Structural Levels ◽  
Identification And Characterization

Membranes based on sulfonated synditoactic polystyrene (s-sPS) were thoroughly characterized by contrast variation small-angle neutron scattering (SANS) over a wide Q-range in dry and hydrated states. Following special sulfonation and treatment procedures, s-sPS is an attractive material for fuel cells and energy storage applications. The film samples were prepared by solid-state sulfonation, resulting in uniform sulfonation of only the amorphous phase while preserving the crystallinity of the membrane. Fullerenes, which improve the resistance to oxidation decomposition, were incorporated in the membranes. The fullerenes seem to be chiefly located in the amorphous regions of the samples, and do not influence the formation and evolution of the morphologies in the polymer films, as no significant differences were observed in the SANS patterns compared to the fullerenes-free s-sPS membranes, which were investigated in a previous study. The use of uniaxially deformed film samples, and neutron contrast variation allowed for the identification and characterization of different structural levels with sizes between nm and μm, which form and evolve in both the dry and hydrated states. The scattering length density of the crystalline regions was varied using the guest exchange procedure between different toluene isotopologues incorporated into the sPS lattice, while the variation of the scattering properties of the hydrated amorphous regions was achieved using different H2O/D2O mixtures. Due to the deformation of the films, the scattering characteristics of different structures can be distinguished on specific detection sectors and at different detection distances after the sample, depending on their size and orientation.

Identification and Characterization of Solid-State Nature of 2-Chloromandelic Acid

2009 ◽  
Vol 98 (5) ◽  
pp. 1835-1844 ◽  
Author(s):  
Quan He ◽  
Jesse Zhu ◽  
Hassan Gomaa ◽  
Michael Jennings ◽  
Sohrab Rohani
Keyword(s):  
Solid State ◽  
Identification And Characterization ◽  
State Nature

The Dynamics of a Molecular Plug Docked onto a Solid-State Nanopore

2018 ◽  
Author(s):  
Xin Shi ◽  
Qiao Li ◽  
Rui Gao ◽  
Wei Si ◽  
Shao-Chuang Liu ◽  
...  
Keyword(s):  
Solid State ◽  
Single Molecule ◽  
Conformational Changes ◽  
Ionic Current ◽  
Observation Time ◽  
Random Coil ◽  
Dna Complexes ◽  
Dna Complex ◽  
Identification And Characterization

<a></a><a>Docking of a protein-DNA complex onto a nanopore can provide ample observation time for a detailed inspection of the complex, enabling collection of biophysical data for detection, identification, and characterization of the biomolecules. While docking of a protein-DNA complex onto a biological nanopore has enabled analytic applications of nanopores including DNA sequencing, the application of the same principle to solid-state nanopores is tempered by poor understanding of the docking process. Here, we elucidate the behaviour of individual protein-DNA complexes docked onto a solid-state nanopore by monitoring the nanopore ionic current. </a><a>Repeat docking of monovalent streptavidin-DNA complexes is found to produce ionic current blockades that fluctuate between discrete levels within the same current blockade. </a>We elucidate the roles of the protein plug and the DNA tether in the docking process, finding the docking configurations to determine the multitude of the current blockade levels whereas the frequency of the current level switching to be determined by the interactions between the molecules and the solid-state membrane. Finally, we prove the feasibility of using the nanopore docking principle for single molecule sensing using solid-state nanopores by detecting conformational changes of a tethered DNA molecule from a random coil to an i-motif states.

The Dynamics of a Molecular Plug Docked onto a Solid-State Nanopore

2018 ◽  
Author(s):  
Xin Shi ◽  
Qiao Li ◽  
Rui Gao ◽  
Wei Si ◽  
Shao-Chuang Liu ◽  
...  
Keyword(s):  
Solid State ◽  
Single Molecule ◽  
Conformational Changes ◽  
Ionic Current ◽  
Observation Time ◽  
Random Coil ◽  
Dna Complexes ◽  
Dna Complex ◽  
Identification And Characterization

<a></a><a>Docking of a protein-DNA complex onto a nanopore can provide ample observation time for a detailed inspection of the complex, enabling collection of biophysical data for detection, identification, and characterization of the biomolecules. While docking of a protein-DNA complex onto a biological nanopore has enabled analytic applications of nanopores including DNA sequencing, the application of the same principle to solid-state nanopores is tempered by poor understanding of the docking process. Here, we elucidate the behaviour of individual protein-DNA complexes docked onto a solid-state nanopore by monitoring the nanopore ionic current. </a><a>Repeat docking of monovalent streptavidin-DNA complexes is found to produce ionic current blockades that fluctuate between discrete levels within the same current blockade. </a>We elucidate the roles of the protein plug and the DNA tether in the docking process, finding the docking configurations to determine the multitude of the current blockade levels whereas the frequency of the current level switching to be determined by the interactions between the molecules and the solid-state membrane. Finally, we prove the feasibility of using the nanopore docking principle for single molecule sensing using solid-state nanopores by detecting conformational changes of a tethered DNA molecule from a random coil to an i-motif states.

scholarly journals Chemically Modified Silica Materials as Model Systems for the Characterization of Water-Surface Interactions

2018 ◽  
Vol 232 (7-8) ◽  
pp. 1127-1146 ◽  
Author(s):  
Martin Brodrecht ◽  
Bharti Kumari ◽  
Hergen Breitzke ◽  
Torsten Gutmann ◽  
Gerd Buntkowsky
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Model Systems ◽  
Guest Molecules ◽  
Aromatic Molecules ◽  
Functionalized Mesoporous Silica ◽  
Line Shape Analysis ◽  
Chemically Modified Silica ◽  
Nmr Techniques

AbstractA series of novel functionalized mesoporous silica-based materials with well-defined pore diameters, surface functionalization and surface morphology is synthesized by co-condensation or grafting techniques and characterized by solid-state NMR spectroscopy, DNP enhanced solid state-NMR and thermodynamic techniques. These materials are employed as host-systems for small-guest molecules like water, small alcohols, carbonic acids, small aromatic molecules, binary mixtures and others. The phase-behavior of these confined guests is studied by combinations of one dimensional solid-state NMR techniques (1H MAS,2H-line shape analysis,13C CPMAS) and two-dimensional correlation experiments like1H-29Si- solid-state HETCOR.

Tuning the configuration of the flexible metal–alkene-framework affords pure cycloisomers in solid state photodimerization

2021 ◽  
Author(s):  
Yong Wang ◽  
Meng-Fan Wang ◽  
David James Young ◽  
Hua Zhu ◽  
Fei-Long Hu ◽  
...  
Keyword(s):  
Solid State ◽  
Cycloaddition Reaction ◽  
Guest Molecules ◽  
Flexible Metal

The bulkiness of the guest molecules influences the conformations of the ligand and the final outcomes of the cycloaddition reaction.

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