Nanofibrillar Stimulus‐Responsive Cholesteric Microgels with Catalytic Properties

Abstract

We report composite stimulus-responsive cholesteric catalytically active microgels derived from filamentous supramolecular building blocks:cellulose nanocrystals (CNCs). The variation in the microgel dimensions and pitchi nr esponse to the change in ambient conditions was governed by the polymer component. The cholesteric morphology of the microgels resulted from the self-organization of CNCs in spherical confinement. The microgels exhibited excellent structural integrity and functioned as microreactors in catalytic hydrolysis reactions and in the synthesis of metal nanoparticles. Because of these collective properties,t he reported microgels show muchpromise for application in the design of functional responsive materials.

Nanocolloidal Hydrogel for Heavy Metal Scavenging

“…To increase the rate of metal ion uptake, we prepared nanocolloidal aCNC/ aGQD microgels by using a microfluidic method. 43 A stream of mixed aCNC/aGQD suspension was supplied at a volumetric flow rate of 0.4 mL/h to the MF droplet generator (Figure S12) to form precursor droplets dispersed in F-oil that was introduced in the microfluidics (MF) device at a flow rate of 6 mL/h. The droplets were collected at the exit of the device and allowed to gel for 2 h. Figure 4a shows the aCNC/aGQD microgels in F-oil with a mean diameter of 190 μm, which were prepared at R = 1.0 and C tot = 80 mg/mL.…”

“…The microgels were stored for 24 h in F-oil and subsequently transferred to deionized water by the consecutive exchange of F-oil with F-oil containing 10 wt % perfluorooctanol, hexane with 0.5 wt % Span 80, and pure hexane. 43 Figure 4c shows the microgels suspended in deionized water. The microgels had an average size of 220 μm; that is, upon their transfer in water, they underwent ∼15% swelling (Figure S13).…”

Relaxation dynamics in bio-colloidal cholesteric liquid crystals confined to cylindrical geometry

“…In the modeling used in this study based on Eqs. (5)(6)(7)(8)(9)(10)(11), there is no external stress (see Supplementary Note 15). Furthermore, hydrodynamics is reasonably negligible because of three reasons.…”

“…Through this thermodynamically driven relaxation, unwound helices forming a para-nematic state are spontaneously self-reconstructed leading to a chiral ground state; the PN–N* transition is thus self-driven. The dynamics of self-reconstruction (relaxation) in biological chiral lyotropic liquid crystals (BCLLCs) is of particular interest for forming retarder films and cholesterol color filters 3 , plasmonic mesostructured materials 4 , stimuli-responsive materials design 2 , 5 – 8 , and processing of advanced materials 9 such as biomimetic film formation 10 , 11 replicating, for example, structural motifs of cortical bone and cornea 12 , 13 . Despite its importance, the prediction and quantification of the relaxation dynamics of BCLLCs have remained up to date non-trivial and challenging both experimentally and theoretically.…”

Microfluidic synthesis of elastomeric microparticles: A case study in catalysis of palladium‐mediated cross‐coupling

“…Over the past decade, multiphase microfluidic strategies, owing to their consistent microdroplet formation and high‐throughput production capabilities, have been utilized for synthesis of a wide range of microparticles including hydrogels and microgels . Polymerization of microgels is typically conducted in two discrete steps, a droplet generation, followed by a cross‐linking initiation through a temperature gradient, UV light irradiation, or chemical reaction in the presence of a polymerization catalyst .…”