Nano‐ and Microsized Cubic Gel Particles from Cyclodextrin Metal–Organic Frameworks

Abstract

The bottom-up control of the three-dimensional shapes of objects in a wide range of sizes, from nanometer to millimeter, has attracted attention in diverse fields. [1,2] For instance, metal nanocrystals having various shapes, such as spherical, cubic, hexagonal plate, and octahedral, have been extensively investigated owing to interest in crystal growth [3] and the control of catalytic activities. [4] Among the inorganic metal oxides and minerals, for example, the crystallization and morphology control of CaCO 3 have been of interest for decades, with relation to biomineralization, to produce the more complex structures that living organisms produce. [5] More recently, sol-gel polymerization using the surface of supramolecular assemblies as templates has been extensively investigated for the fabrication of various well-defined nanoand microsized objects such as mesoporous silica, [6] hollow tubes, [7] and helical ribbon structures. [8] In spite of diverse approaches for controlling the sizes and shapes of inorganic materials in the micro and nanometer ranges, less attention has been paid to organic network polymers, because the network polymers are generally not moldable nor can be processed after formation of the networks as they are insoluble in all solvents and have no observed melting points. As a bottom-up approach, emulsion polymerization using micelles and vesicles as templates produce spherical particles, [9] hollow spherical particles, [10] and a layer structure, [11] whereas the top-down approaches, nanoimprint lithography [12] with photoresist and three-dimensional microfabrication by two-photon laser chemistry, [13] have been reported for controlling the network polymers to form

Investigation of cellulose acetate/gamma‐cyclodextrin MOF based mixed matrix membranes for CO2/CH4 gas separation

“…XRD results of both CA and γ -CD-MOF are according to the literature. 34,[49][50][51][52] In the XRD graph of CA/γ -CD-MOF 0.2 wt.% membrane sample, the peak of both CA and γ -CD-MOF shifts towards higher angle, that is, 2θ = 13.5°and 2θ = 23°a nd 2θ = 5.2°, 2θ = 7.5°, 2θ = 17.5°, respectively. This might be due to the fact that quantity of MOF is less in polymer matrix.…”

“…The formation of crystals is achieved through vapor diffusion method. 26,27 The γ -CD-MOF have body-centered cubic structure, large spherical pore of 1.7 nm in particle size having eight glucose unit, molecular weight M w 1297 g•mol −1 and a cavity diameter range of 0.75-0.95 nm. The most promising feature that distinguishes γ -CD-MOF from the rest of MOFs is having an abundant number of hydroxyl ions in a single molecule.…”

Multiple patterns of polymer gels in microspheres due to the interplay among phase separation, wetting, and gelation

“…For example, photolithography and two-photon polymerization allow the regulation of gel patterns at the mesoscale (2)(3)(4). The advanced design of the molecules enables polymerization with a self-assembly and produces nonspherical microgels: spherical particles with a cavity, capsules, and cubic particles (5)(6)(7). However, these methods require highly specialized equipment and are generally difficult to adapt for biopolymer gels.…”

Porous β-cyclodextrin nanotubular assemblies enable high-efficiency removal of bisphenol micropollutants from aquatic systems

“…β-CD NFs were produced via the procedure of cross linking and subsequent decomposition of metal-organic bonds by using the MOF as sacrificial template (Fig. 1(a)) [51]. The template, named as β-Cu-MOF NFs, was synthesized and characterized by single-crystal X-ray structure analysis.…”