Kinetics of pressure induced structural changes in super- or near-critical CO<sub>2</sub>-microemulsions

Müller, Alexander; Pütz, Yvonne; Oberhoffer, Roland; Becker, Nils B.; Strey, R.; Wiedenmann, A.; Sottmann, Thomas

doi:10.1039/c3cp53790k

Cited by 15 publications

(10 citation statements)

References 47 publications

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“…Hence, subsequently we used a home built stroboscopic high pressure SANS cell and studied the kinetics of pressure induced structural changes performing SANS measurements at a sample to detector distance of 39 m 46 . Repeating the pressure jump cycles (200 bar → 40 bar → 200 bar) 5400 times enabled us to obtain scattering curves with a reasonable statistic (Fig.…”

Section: Resultsmentioning

confidence: 99%

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Volume phase transition kinetics of smart N-n-propylacrylamide microgels studied by time-resolved pressure jump small angle neutron scattering

Wrede

Reimann

Lülsdorf

et al. 2018

Sci Rep

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The use of smart colloidal microgels for advanced applications critically depends on their response kinetics. We use pressure jump small angle neutron scattering with supreme time resolution to study the rapid volume phase transition kinetics of such microgels. Utilizing the pressure induced microphase separation inside the microgels we were able to resolve their collapse and swelling kinetics. While the collapse occurs on a time scale of 10 ms, the particle swelling turned out to be much faster. Photon correlation spectroscopy and static small angle neutron scattering unambiguously show, that the much slower collapse can be associated with the complex particle architecture exhibiting a loosely-crosslinked outer region and a denser inner core region. These insights into the kinetics of stimuli-responsive materials are of high relevance for their applications as nano-actuators, sensors or drug carriers. Moreover, the used refined pressure jump small angle neutron scattering technique is of broad interest for soft matter studies.

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Section: Resultsmentioning

confidence: 99%

“…The pressure jump measurements were performed in a home built stroboscopic high pressure SANS cell (SHP-SANS) 46 . The cell, which can be filled with liquids as well as gases, was designed by the mechanical workshop of the Institute of Physical Chemistry at the University of Cologne.…”

Section: Methodsmentioning

confidence: 99%

Volume phase transition kinetics of smart N-n-propylacrylamide microgels studied by time-resolved pressure jump small angle neutron scattering

Wrede

Reimann

Lülsdorf

et al. 2018

Sci Rep

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“…A high-pressure cell, previously described by Pütz et al ., was utilized for the measurements. 34 , 35 Further technical details are provided in the SI .…”

Section: Methodsmentioning

confidence: 99%

Pressure-Responsive, Surfactant-Free CO₂-Based Nanostructured Fluids

Grimaldi¹,

Rojas

Stehle

et al. 2017

ACS Nano

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Microemulsions are extensively used in advanced material and chemical processing. However, considerable amounts of surfactant are needed for their formulation, which is a drawback due to both economic and ecological reasons. Here, we describe the nanostructuration of recently discovered surfactant-free, carbon dioxide (CO2)-based microemulsion-like systems in a water/organic-solvent/CO2 pressurized ternary mixture. “Water-rich” nanodomains embedded into a “water-depleted” matrix have been observed and characterized by the combination of Raman spectroscopy, molecular dynamics simulations, and small-angle neutron scattering. These single-phase fluids show a reversible, pressure-responsive nanostructuration; the “water-rich” nanodomains at a given pressure can be instantaneously degraded/expanded by increasing/decreasing the pressure, resulting in a reversible, rapid, and homogeneous mixing/demixing of their content. This pressure-triggered responsiveness, together with other inherent features of these fluids, such as the absence of any contaminant in the ternary mixture (e.g., surfactant), their spontaneous formation, and their solvation capability (enabling the dissolution of both hydrophobic and hydrophilic molecules), make them appealing complex fluid systems to be used in molecular material processing and in chemical engineering.

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“…On-line neutron scattering investigations of poly(dimethylsiloxane) polymer-ScCO 2 solvent phase diagrams were performed and fundamental applications demonstrated [81]. Time-resolved scattering experiments where the ScCO 2 to CO 2 transition was used as a foaming agent to create micro and nano foams allowed the kinetics of foam formation to be studied as a function of pressure and pressure modulation [82]. The use of fluorinated surfactants in CO 2 microemulsions is widespread but not desired for environmental reasons.…”

Section: Stop Flow/chemistry On-linementioning

confidence: 99%

Soft Matter Sample Environments for Time-Resolved Small Angle Neutron Scattering Experiments: A Review

et al. 2021

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With the promise of new, more powerful neutron sources in the future, the possibilities for time-resolved neutron scattering experiments will improve and are bound to gain in interest. While there is already a large body of work on the accurate control of temperature, pressure, and magnetic fields for static experiments, this field is less well developed for time-resolved experiments on soft condensed matter and biomaterials. We present here an overview of different sample environments and technique combinations that have been developed so far and which might inspire further developments so that one can take full advantage of both the existing facilities as well as the possibilities that future high intensity neutron sources will offer.

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Kinetics of pressure induced structural changes in super- or near-critical CO₂-microemulsions

Cited by 15 publications

References 47 publications

Volume phase transition kinetics of smart N-n-propylacrylamide microgels studied by time-resolved pressure jump small angle neutron scattering

Volume phase transition kinetics of smart N-n-propylacrylamide microgels studied by time-resolved pressure jump small angle neutron scattering

Pressure-Responsive, Surfactant-Free CO₂-Based Nanostructured Fluids

Soft Matter Sample Environments for Time-Resolved Small Angle Neutron Scattering Experiments: A Review

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Kinetics of pressure induced structural changes in super- or near-critical CO2-microemulsions

Cited by 15 publications

References 47 publications

Volume phase transition kinetics of smart N-n-propylacrylamide microgels studied by time-resolved pressure jump small angle neutron scattering

Volume phase transition kinetics of smart N-n-propylacrylamide microgels studied by time-resolved pressure jump small angle neutron scattering

Pressure-Responsive, Surfactant-Free CO2-Based Nanostructured Fluids

Soft Matter Sample Environments for Time-Resolved Small Angle Neutron Scattering Experiments: A Review

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Product

Resources

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Kinetics of pressure induced structural changes in super- or near-critical CO₂-microemulsions

Pressure-Responsive, Surfactant-Free CO₂-Based Nanostructured Fluids