scholarly journals Controlled sequential assembly of metal-organic polyhedra into colloidal gels with high chemical complexity

2021 ◽  
Author(s):  
Min Ying Tsang ◽  
Shun Tokuda ◽  
Po-Chun Han ◽  
Zaoming Wang ◽  
Alexandre Legrand ◽  
...  
Keyword(s):  
Colloidal Particles ◽  
Soft Materials ◽  
Chemical Components ◽  
Colloidal System ◽  
Synthetic Process ◽  
Chemical Complexity ◽  
Porous Networks ◽  
Synthetic Strategy ◽  
Colloidal Gel ◽  
Metal Organic

Assembling many chemical components into a material in a controlled manner is one of the biggest challenges in chemistry. Particularly porous materials with multivariate character within their scaffolds are expected to demonstrate synergistic properties. In this study, we show a synthetic strategy to construct porous networks with multiple chemical components. By taking advantage of the hierarchical nature of a colloidal system based on metal-organic polyhedra (MOPs), we developed a two-step assembly process to form colloidal networks; assembling of MOPs with the organic linker to the formation of MOP network as a colloidal particle, followed by further connecting colloids by additional crosslinkers, leading to colloidal networks. This synthetic process allows not only for the use of different organic linkers for connecting MOPs and colloidal particles, respectively, but for assembling different colloidal particles formed by various MOPs. The proof-of-concept of this tuneable multivariate colloidal gel system offers an alternative to developing functional porous soft materials with multifunction.

Spatiotemporal Control of Supramolecular Polymerization and Gelation of Metal-Organic Polyhedra

2020 ◽  
Author(s):  
alexandre legrand ◽  
Li-Hao Liu ◽  
Philipp Royla ◽  
Takuma Aoyama ◽  
Gavin Craig ◽  
...  
Keyword(s):  
Acid Concentration ◽  
Self Assembly ◽  
Colloidal Particles ◽  
Soft Materials ◽  
Supramolecular Materials ◽  
Time Resolved ◽  
Colloidal Gel ◽  
Metal Organic ◽  
Spatiotemporal Control ◽  
Gel Network

In coordination-based supramolecular materials such as metallogels, simultaneous temporal and spatial control of their assembly remains challenging. Here, we demonstrate that the combination of light with acids as stimuli allows for the spatiotemporal control over the architectures, mechanical properties, and shape of porous soft materials based on metal-organic polyhedra (MOPs). First, we show that the formation of a colloidal gel network from a preformed kinetically trapped MOP solution can be triggered upon addition of trifluoroacetic acid (TFA), and that acid concentration determines the reaction kinetics. As determined by time-resolved dynamic light scattering, UV-vis absorption and <sup>1</sup>H NMR spectroscopies and rheology measurements, the consequences of the increase in acid concentration are (i) an increase in the cross-linking between MOPs; (ii) a growth in the size of the colloidal particles forming the gel network; (iii) an increase in the density of the colloidal network; and (iv) a decrease in the ductility and stiffness of the resulting gel. We then demonstrate that irradiation of a dispersed photoacid generator, pyranine, allows the spatiotemporal control of the gel formation by locally triggering the self-assembly process. Using this methodology, we show that the gel can be patterned into a desired shape. Such precise positioning of the assembled structures, combined with the stable and permanent porosity of MOPs, could allow their integration into devices for applications such as sensing, separation, catalysis, or drug release.

scholarly journals Spatiotemporal Control of Supramolecular Polymerization and Gelation of Metal-Organic Polyhedra

2020 ◽  
Author(s):  
alexandre legrand ◽  
Li-Hao Liu ◽  
Philipp Royla ◽  
Takuma Aoyama ◽  
Gavin Craig ◽  
...  
Keyword(s):  
Acid Concentration ◽  
Self Assembly ◽  
Colloidal Particles ◽  
Soft Materials ◽  
Supramolecular Materials ◽  
Time Resolved ◽  
Colloidal Gel ◽  
Metal Organic ◽  
Spatiotemporal Control ◽  
Gel Network

In coordination-based supramolecular materials such as metallogels, simultaneous temporal and spatial control of their assembly remains challenging. Here, we demonstrate that the combination of light with acids as stimuli allows for the spatiotemporal control over the architectures, mechanical properties, and shape of porous soft materials based on metal-organic polyhedra (MOPs). First, we show that the formation of a colloidal gel network from a preformed kinetically trapped MOP solution can be triggered upon addition of trifluoroacetic acid (TFA), and that acid concentration determines the reaction kinetics. As determined by time-resolved dynamic light scattering, UV-vis absorption and <sup>1</sup>H NMR spectroscopies and rheology measurements, the consequences of the increase in acid concentration are (i) an increase in the cross-linking between MOPs; (ii) a growth in the size of the colloidal particles forming the gel network; (iii) an increase in the density of the colloidal network; and (iv) a decrease in the ductility and stiffness of the resulting gel. We then demonstrate that irradiation of a dispersed photoacid generator, pyranine, allows the spatiotemporal control of the gel formation by locally triggering the self-assembly process. Using this methodology, we show that the gel can be patterned into a desired shape. Such precise positioning of the assembled structures, combined with the stable and permanent porosity of MOPs, could allow their integration into devices for applications such as sensing, separation, catalysis, or drug release.

scholarly journals Multiscale Structural Control of Linked Metal-Organic Polyhedra Gel by Aging-Induced Linkage-Reorganization

2021 ◽  
Author(s):  
Zaoming Wang ◽  
Christian Villa Santos ◽  
alexandre legrand ◽  
Frederik Haase ◽  
Yosuke Hara ◽  
...  
Keyword(s):  
Structural Control ◽  
Colloidal Particles ◽  
Hierarchical Structures ◽  
Porous Metal ◽  
Soft Materials ◽  
Supramolecular Polymer ◽  
Polymer Systems ◽  
Multiple Length Scales ◽  
Metal Organic ◽  
Supramolecular Networks

Assembly of permanently porous metal-organic cages with functional polymers forms soft supramolecular networks featuring both porosity and processability. However, the amorphous nature of such soft materials complicates their characterization and thus limits structural control. Here we demonstrated that aging is an effective strategy to control the hierarchical network of supramolecular gels, which are assembled from organic ligands as linkers and metal-organic polyhedra (MOP) as junctions. Normally, the initial gel formation by rapid gelation leads to a kinetically trapped structure with low controllability. Through a controlled post-synthetic aging process, we show that it is possible to tune the network of the linked MOP gel over multiple length scales. This process allows control on the molecular-scale rearrangement of interlinking MOPs, mesoscale fusion of colloidal particles and macroscale densification of the whole colloidal network. In this work we elucidate the relationships between the gel properties, such as porosity and rheology, and their hierarchical structures, which suggest that porosity measurement can be used as a powerful tool to characterize the microscale structural transition of the amorphous gels. This aging strategy can be applied in other supramolecular polymer systems particularly containing kinetically controlled structures and shows an opportunity to engineer the structure and porosity of amorphous porous soft materials for further applications.

scholarly journals Multiscale Structural Control of Linked Metal-Organic Polyhedra Gel by Aging-Induced Linkage-Reorganization

2021 ◽  
Author(s):  
Zaoming Wang ◽  
Christian Villa Santos ◽  
alexandre legrand ◽  
Frederik Haase ◽  
Yosuke Hara ◽  
...  
Keyword(s):  
Structural Control ◽  
Colloidal Particles ◽  
Hierarchical Structures ◽  
Porous Metal ◽  
Soft Materials ◽  
Supramolecular Polymer ◽  
Polymer Systems ◽  
Multiple Length Scales ◽  
Metal Organic ◽  
Supramolecular Networks

Assembly of permanently porous metal-organic cages with functional polymers forms soft supramolecular networks featuring both porosity and processability. However, the amorphous nature of such soft materials complicates their characterization and thus limits structural control. Here we demonstrated that aging is an effective strategy to control the hierarchical network of supramolecular gels, which are assembled from organic ligands as linkers and metal-organic polyhedra (MOP) as junctions. Normally, the initial gel formation by rapid gelation leads to a kinetically trapped structure with low controllability. Through a controlled post-synthetic aging process, we show that it is possible to tune the network of the linked MOP gel over multiple length scales. This process allows control on the molecular-scale rearrangement of interlinking MOPs, mesoscale fusion of colloidal particles and macroscale densification of the whole colloidal network. In this work we elucidate the relationships between the gel properties, such as porosity and rheology, and their hierarchical structures, which suggest that porosity measurement can be used as a powerful tool to characterize the microscale structural transition of the amorphous gels. This aging strategy can be applied in other supramolecular polymer systems particularly containing kinetically controlled structures and shows an opportunity to engineer the structure and porosity of amorphous porous soft materials for further applications.

Metal-organic-framework derived hollow manganese nickel selenide spheres confined with nanosheets on nickel foam for hybrid supercapacitors

2021 ◽  
Author(s):  
Bahareh ameri ◽  
Akbar Mohammadi Zardkhoshoui ◽  
Saied Saeed Hosseiny Davarani
Keyword(s):  
Active Sites ◽  
Nickel Foam ◽  
Metal Organic Framework ◽  
High Surface ◽  
Metal Organic Frameworks ◽  
High Surface Area ◽  
Supercapacitive Performance ◽  
Hybrid Supercapacitors ◽  
Porous Networks ◽  
Metal Organic

Metal-organic frameworks (MOFs) derived nanoarchitectures have special features, such as high surface area (SA), abundant active sites, exclusive porous networks, and remarkable supercapacitive performance when compared to traditional nanoarchitectures. Herein,...

scholarly journals Electric double layer and electrokinetic potential of pectic macromolecules in sugar beet

2008 ◽  
pp. 21-28
Author(s):  
Tatjana Kuljanin ◽  
Ljubinko Levic ◽  
Nevena Misljenovic ◽  
Gordana Koprivica
Keyword(s):  
Sugar Beet ◽  
Double Layer ◽  
Electric Double Layer ◽  
Colloidal Particles ◽  
Colloidal Particle ◽  
Electrokinetic Potential ◽  
Shear Plane ◽  
Colloidal System ◽  
Cu Ions ◽  
Measurable Property

Electrokinetic potential is an important property of colloidal particles and, regarding the fact that it is a well defined and easily measurable property, it is considered to be a permanent characteristic of a particular colloidal system. In fact, it is a measure of electrokinetic charge that surrounds the colloidal particle in a solution and is in direct proportion with the mobility of particles in an electric field. Gouy-Chapman-Stern-Graham's model of electric double layer was adopted and it was proven experimentally that the addition of Cu++ ions to sugar beet pectin caused a reduction in the negative electrokinetic potential proportional to the increase of Cu++ concentration. Higher Cu++ concentrations increased the proportion of cation specific adsorption (Cu++ and H+) with regard to electrostatic Coulombic forces. Consequently, there is a shift in the shear plane between the fixed and diffuse layers directed towards the diffuse layer, i.e. towards its compression and decrease in the electrokinetic potential or even charge inversion of pectin macromolecules.

scholarly journals Mixed-order phase transition in a colloidal crystal

2017 ◽  
Vol 114 (49) ◽  
pp. 12906-12909 ◽  
Author(s):  
Ricard Alert ◽  
Pietro Tierno ◽  
Jaume Casademunt
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Colloidal Particles ◽  
Colloidal Crystal ◽  
Equilibrium Phase ◽  
Mean Field ◽  
Critical Dimension ◽  
Colloidal System ◽  
Test Bed ◽  
Mixed Order

Mixed-order phase transitions display a discontinuity in the order parameter like first-order transitions yet feature critical behavior like second-order transitions. Such transitions have been predicted for a broad range of equilibrium and nonequilibrium systems, but their experimental observation has remained elusive. Here, we analytically predict and experimentally realize a mixed-order equilibrium phase transition. Specifically, a discontinuous solid–solid transition in a 2D crystal of paramagnetic colloidal particles is induced by a magnetic field H. At the transition field Hs, the energy landscape of the system becomes completely flat, which causes diverging fluctuations and correlation length ξ∝|H2−Hs2|−1/2. Mean-field critical exponents are predicted, since the upper critical dimension of the transition is du=2. Our colloidal system provides an experimental test bed to probe the unconventional properties of mixed-order phase transitions.

scholarly journals Aggregation kinetics of irreversible patches coupled with reversible isotropic interaction leading to chains, bundles and globules

2018 ◽  
Vol 90 (6) ◽  
pp. 1085-1098 ◽  
Author(s):  
Isha Malhotra ◽  
Sujin B. Babu
Keyword(s):  
Self Assembly ◽  
Patch Size ◽  
Colloidal Particles ◽  
Volume Fraction ◽  
Interaction Strength ◽  
Colloidal System ◽  
Angle Distribution ◽  
Volume Fractions ◽  
Low Volume ◽  
A Chain

Abstract In the present study we are performing simulation of simple model of two patch colloidal particles undergoing irreversible diffusion limited cluster aggregation using patchy Brownian cluster dynamics. In addition to the irreversible aggregation of patches, the spheres are coupled with isotropic reversible aggregation through the Kern–Frenkel potential. Due to the presence of anisotropic and isotropic potential we have also defined three different kinds of clusters formed due to anisotropic potential and isotropic potential only as well as both the potentials together. We have investigated the effect of patch size on self-assembly under different solvent qualities for various volume fractions. We will show that at low volume fractions during aggregation process, we end up in a chain conformation for smaller patch size while in a globular conformation for bigger patch size. We also observed a chain to bundle transformation depending on the attractive interaction strength between the chains or in other words depending on the quality of the solvent. We will also show that bundling process is very similar to nucleation and growth phenomena observed in colloidal system with short range attraction. We have also studied the bond angle distribution for this system, where for small patches only two angles are more probable indicating chain formation, while for bundling at very low volume fraction a tail is developed in the distribution. While for the case of higher patch angle this distribution is broad compared to the case of low patch angles showing we have a more globular conformation. We are also proposing a model for the formation of bundles which are similar to amyloid fibers using two patch colloidal particles.

scholarly journals Bidirectional rotation control of a carbon fiber in nematic liquid crystal using AC electric field

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jun-Yong Lee ◽  
Jeong-Seon Yu ◽  
Jong-Hyun Kim
Keyword(s):  
Free Energy ◽  
Liquid Crystal ◽  
Electric Field ◽  
Colloidal Particles ◽  
Colloidal System ◽  
Wide Angle ◽  
Local Minima ◽  
Free Energies ◽  
Rotation Direction ◽  
Ac Electric Field

Abstract Colloidal particles dispersed in nematic liquid crystals are aligned along the orientation that minimizes the elastic free energy. Through applying an electric field to a nematic colloidal system, the orientation of the director can change. Consequently, colloidal particles realign to minimize the total free energy, which is the sum of the elastic and electric free energies. Herein, we demonstrate that if the preferred rotation directions given by the electric and elastic free energies are different during realignment, the rotation direction of the particle can be controlled by how we apply the electric field. When the strength of the electric field gradually increases, the particles rotate in the same direction as the rotation of the director. However, when a sufficiently high electric field is suddenly applied, the particles rotate in the opposite direction. In this study, we analyzed the effect of free energy on the bidirectional rotation behavior of the particles using a theoretical model. This study provides an effective approach to control the rotational behavior of colloidal particles over a wide-angle range between two orientational local minima.

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