Probing the Dynamic Self-Assembly Behaviour of Photoswitchable Wormlike Micelles in Real Time

2018 ◽  
Author(s):  
Elaine A. Kelly ◽  
Judith E. Houston ◽  
Rachel Evans
Keyword(s):  
Real Time ◽  
Absorption Spectroscopy ◽  
Self Assembly ◽  
Uv Light ◽  
Wormlike Micelles ◽  
Tetraethylene Glycol ◽  
Light Illumination ◽  
First Time ◽  
Dependent Processes

Understanding the dynamic self-assembly behaviour of azobenzene photosurfactants (AzoPS) is crucial to advance their use in controlled release applications such as<i></i>drug delivery and micellar catalysis. Currently, their behaviour in the equilibrium <i>cis-</i>and <i>trans</i>-photostationary states is more widely understood than during the photoisomerisation process itself. Here, we investigate the time-dependent self-assembly of the different photoisomers of a model neutral AzoPS, <a>tetraethylene glycol mono(4′,4-octyloxy,octyl-azobenzene) </a>(C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>) using small-angle neutron scattering (SANS). We show that the incorporation of <i>in-situ</i>UV-Vis absorption spectroscopy with SANS allows the scattering profile, and hence micelle shape, to be correlated with the extent of photoisomerisation in real-time. It was observed that C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>could switch between wormlike micelles (<i>trans</i>native state) and fractal aggregates (under UV light), with changes in the self-assembled structure arising concurrently with changes in the absorption spectrum. Wormlike micelles could be recovered within 60 seconds of blue light illumination. To the best of our knowledge, this is the first time the degree of AzoPS photoisomerisation has been tracked <i>in</i><i>-situ</i>through combined UV-Vis absorption spectroscopy-SANS measurements. This technique could be widely used to gain mechanistic and kinetic insights into light-dependent processes that are reliant on self-assembly.

Probing the Dynamic Self-Assembly Behaviour of Photoswitchable Wormlike Micelles in Real Time

2018 ◽  
Author(s):  
Elaine A. Kelly ◽  
Judith E. Houston ◽  
Rachel Evans
Keyword(s):  
Real Time ◽  
Absorption Spectroscopy ◽  
Self Assembly ◽  
Uv Light ◽  
Wormlike Micelles ◽  
Tetraethylene Glycol ◽  
Light Illumination ◽  
First Time ◽  
Dependent Processes

Understanding the dynamic self-assembly behaviour of azobenzene photosurfactants (AzoPS) is crucial to advance their use in controlled release applications such as<i></i>drug delivery and micellar catalysis. Currently, their behaviour in the equilibrium <i>cis-</i>and <i>trans</i>-photostationary states is more widely understood than during the photoisomerisation process itself. Here, we investigate the time-dependent self-assembly of the different photoisomers of a model neutral AzoPS, <a>tetraethylene glycol mono(4′,4-octyloxy,octyl-azobenzene) </a>(C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>) using small-angle neutron scattering (SANS). We show that the incorporation of <i>in-situ</i>UV-Vis absorption spectroscopy with SANS allows the scattering profile, and hence micelle shape, to be correlated with the extent of photoisomerisation in real-time. It was observed that C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>could switch between wormlike micelles (<i>trans</i>native state) and fractal aggregates (under UV light), with changes in the self-assembled structure arising concurrently with changes in the absorption spectrum. Wormlike micelles could be recovered within 60 seconds of blue light illumination. To the best of our knowledge, this is the first time the degree of AzoPS photoisomerisation has been tracked <i>in</i><i>-situ</i>through combined UV-Vis absorption spectroscopy-SANS measurements. This technique could be widely used to gain mechanistic and kinetic insights into light-dependent processes that are reliant on self-assembly.

Probing the dynamic self-assembly behaviour of photoswitchable wormlike micelles in real-time

Soft Matter ◽  
2019 ◽  
Vol 15 (6) ◽  
pp. 1253-1259 ◽  
Author(s):  
Elaine A. Kelly ◽  
Judith E. Houston ◽  
Rachel C. Evans
Keyword(s):  
Neutron Scattering ◽  
Real Time ◽  
Absorption Spectroscopy ◽  
Small Angle ◽  
Self Assembly ◽  
Small Angle Neutron Scattering ◽  
Wormlike Micelles

UV-Vis absorption spectroscopy is combined with small-angle neutron scattering to monitor the dynamic self-assembly of an azobenzene photosurfactant from worm-like micelles to fractals during photoisomerization.

scholarly journals PhotoATRP Induced Self-Assembly (PhotoATR-PISA) Enables Simplified Synthesis of Responsive Polymer Nanoparticles in One-Pot

2020 ◽  
Author(s):  
Ali Shahrokhinia ◽  
Randall Scanga ◽  
Priyanka Biswas ◽  
James Reuther
Keyword(s):  
Self Assembly ◽  
Glycidyl Methacrylate ◽  
Uv Light ◽  
Copper Catalyst ◽  
Crosslinking Agent ◽  
Polymer Nanoparticles ◽  
One Pot ◽  
Responsive Polymer ◽  
Catalyst Systems ◽  
First Time

<p><b>ABSTRACT:</b> Photo-controlled atom transfer radical polymerization (PhotoATRP) was implemented, for the first time, to accomplish polymerization induced self-assembly (PISA) mediated by UV light (λ = 365 nm) using ppm levels (ca. < 20 ppm) of copper catalyst at ambient temperature. Using Cu<sup>II</sup>Br<sub>2</sub>/tris(pyridin-2-ylmethyl)amine (TPMA) catalyst systems, PISA was per-formed all in one-pot starting from synthesis of solvophilic poly(oligo(ethylene oxide) methyl ether methacrylate) (POEGMA) blocks to core-crosslinked nanoparticles (NPs) utilizing poly(glycidyl methacrylate) (PGMA) and N,N-cystamine bismethacrylamide (CBMA) as the solvophobic copolymer and crosslinking agent, respectively. Sequential chain-extensions were performed for PGMA demonstrating capabilities for accessing multi-block copolymers with temporal control via switching the UV light on and off. Further, core-crosslinking of PISA nanoparticles was performed via the slow incorporation of the CBMA enabling one-pot crosslinking during the PISA process. Finally, the disulfide installed in the CBMA core-crosslinks allowed for the stimuli-triggered dissociation of nanoparticles using DL-dithiothreitol at acidic pH.</p>

scholarly journals Monitoring Nanocrystal Self‐Assembly in Real Time Using In Situ Small‐Angle X‐Ray Scattering

Small ◽  
2019 ◽  
Vol 15 (20) ◽  
pp. 1900438 ◽  
Author(s):  
Irina Lokteva ◽  
Michael Koof ◽  
Michael Walther ◽  
Gerhard Grübel ◽  
Felix Lehmkühler
Keyword(s):  
Real Time ◽  
Small Angle ◽  
Self Assembly ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

In situ growth and optical gas adsorption performance of Zn(ii) metal–organic framework membranes at room temperature

The Analyst ◽  
2019 ◽  
Vol 144 (16) ◽  
pp. 4887-4896 ◽  
Author(s):  
Mariyemu Tuergong ◽  
Patima Nizamidin ◽  
Abliz Yimit ◽  
Rena Simayi
Keyword(s):  
Room Temperature ◽  
Gas Adsorption ◽  
Uv Light ◽  
Metal Organic Framework ◽  
Adsorption Behaviors ◽  
Uv Light Irradiation ◽  
Unit Surface ◽  
Metal Organic ◽  
First Time

The optical gas adsorption behaviors of [Zn2(bdc)2(dpNDI)]n membranes were studied for the first time. Under UV light irradiation, they exhibited a greater adsorption response to xylene gas with adsorption capacity of 6.46 μg cm−2 per unit surface.

In-Situ Visualization of Evaporation Induced Self-Assembly Phenomena of Nanofluids Detecting the Interfacial Surface Plasmon Reflectance

2015 ◽  
Author(s):  
Iltai (Isaac) Kim ◽  
Kenneth David Kihm
Keyword(s):  
Refractive Index ◽  
Real Time ◽  
Surface Plasmon ◽  
Self Assembly ◽  
Effective Refractive Index ◽  
In Situ Visualization ◽  
Evaporation Induced Self Assembly ◽  
Self Assembled ◽  
Mapping Techniques

Innovative optical techniques based on nano-biophotonics such as surface plasmon resonance (SPR) imaging and R-G-B natural fringe mapping techniques are developed to characterize the transport and optical properties of nanofluids in situ, real-time, and full field manner. Recent results regarding the characterization of nanofluids are summarized and future research directions are presented. 47 nm Al2O3 nanoparticles are dispersed in water with various concentrations. Al2O3 nanofluids droplets are placed on substrates and evaporated in room temperature. In-situ visualization of evaporation-induced self-assembly is conducted to detect concentration, effective refractive index, and different self-assembled pattern including cavity with various nanofluids concentrations and surface hydrophobbicities with SPR and fringe mapping. During the evaporation, time-dependent and near-field nanoparticle concentrations are determined by correlating the SPR reflectance intensities with the effective refractive index (ERI) of the nanofluids. With increasing the concentrations of nanofluids, the existence of hidden complex cavities inside a self-assembled nanocrystalline structure or final dryout pattern is discovered in real-time. R-G-B natural fringe mapping allowed the reconstruction of the 3D cavity formation and crystallization processes quantitatively. The formation of the complex inner structure was found to be attributable to multiple cavity inceptions and their competing growth during the aquatic evaporation. Furthermore, the effect of surface hydrophobicity is examined in the formation of hidden complex cavities, taking place on three different substrates bearing different levels of hydrophobicity; namely, cover glass (CG), gold thin film (Au), and polystyrene dish (PS). These surface plamson resonance imaging and natural fringe mapping techniques are expected to provide a breakthrough in micro-nanoscale thermal fluids phenomena and nano-biochemical sensing when coupled with localized surface Plasmon and metamaterials techniques.

One-pot low-temperature synthesis of TiO2 nanowire/rGO composites with enhanced photocatalytic activity

RSC Advances ◽  
2016 ◽  
Vol 6 (96) ◽  
pp. 94092-94097 ◽  
Author(s):  
Huan Xing ◽  
Wei Wen ◽  
Jin-Ming Wu
Keyword(s):  
Photocatalytic Activity ◽  
Reaction Rate ◽  
Uv Light ◽  
Reaction Rate Constant ◽  
Light Illumination ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis ◽  
One Pot ◽  
Tio2 Nanowire

In situ growth of TiO2 nanowires on graphene oxide was achieved at 80 °C in an open atmosphere. The optimized TiO2/rGO hybrid exhibited a reaction rate constant 5.5 times that of TiO2 nanowires towards photodegradations of rhodamine B in water under the UV light illumination.

scholarly journals Photocatalytic Adsorption Synergistic Degradation of Tetracycline by Z-scheme Bi2WO6/ZIF-8

2021 ◽  
Author(s):  
Xiaojun Dai ◽  
sheng feng ◽  
Wei Wu ◽  
Yun Zhou ◽  
Zhiwei Ye ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Uv Light ◽  
Photogenerated Electron ◽  
Utilization Efficiency ◽  
Electron Hole ◽  
Effects Of Ph ◽  
Growth Method ◽  
Synergistic Degradation ◽  
First Time

Abstract In this paper, in order to improved the photocatalytic activity of Bi2WO6, Bi2WO6 and ZIF-8 were successfully combined by in-situ growth method for the first time. The addition of ZIF-8 effectively inhibited the recombination of photogenerated electron hole pairs and further improved the electron utilization efficiency, and superoxide anion was introduced to greatly improve the photocatalytic activity. The performance of Bi2WO6/ZIF-8 in the photodegradation of tetracycline (TC) was studied under different conditions of proportions of ZIF-8, dosage of catalyst and concentration of TC. The results indicated that B/Z/5/1 (10mg) had the best photocatalytic activity, and 97.8% of TC (20mg/L) could be degraded in 80 minutes under UV light, the rate constant (k) for TC degradation was almost 3 times that of Bi2WO6. The effects of pH, HA and inorganic anions on the degradation of TC were studied in simulated real water. Further, B/Z/5/1 could be reutilized up to five cycles without reduction of efficiency and catalysis performance. Therefore, Bi2WO6/ZIF-8 heterojunction composite material can be utilized as an efficient photocatalyst for remediation of environmental pollution.

scholarly journals Graphene transistors for real-time monitoring molecular self-assembly dynamics

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Marco Gobbi ◽  
Agostino Galanti ◽  
Marc-Antoine Stoeckel ◽  
Bjorn Zyska ◽  
Sara Bonacchi ◽  
...  
Keyword(s):  
Real Time ◽  
Self Assembly ◽  
Molecular Assembly ◽  
Self Organization ◽  
Highly Sensitive ◽  
Graphene Devices ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Molecular Ensemble

Abstract Mastering the dynamics of molecular assembly on surfaces enables the engineering of predictable structural motifs to bestow programmable properties upon target substrates. Yet, monitoring self-assembly in real time on technologically relevant interfaces between a substrate and a solution is challenging, due to experimental complexity of disentangling interfacial from bulk phenomena. Here, we show that graphene devices can be used as highly sensitive detectors to read out the dynamics of molecular self-assembly at the solid/liquid interface in-situ. Irradiation of a photochromic molecule is used to trigger the formation of a metastable self-assembled adlayer on graphene and the dynamics of this process are monitored by tracking the current in the device over time. In perspective, the electrical readout in graphene devices is a diagnostic and highly sensitive means to resolve molecular ensemble dynamics occurring down to the nanosecond time scale, thereby providing a practical and powerful tool to investigate molecular self-organization in 2D.

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