Controllable synthesis of patchy particles with tunable geometry and orthogonal chemistry

Chang, Fuqiang; Ouhajji, Samia; Townsend, Alice; Lacina, Kanvaly S.; Ravensteijn, Bas G. P. van; Kegel, Willem K.

doi:10.1016/j.jcis.2020.08.038

Cited by 15 publications

(9 citation statements)

References 49 publications

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“…Reversible hydrophilization has been reported using molecular surfactants such as cetrimonium bromide (CTAB) [54] or didodecyldimethylammonium bromide (DDAB)[ 53 , 55 ] to tune the contact angle of the hydrophilic silica spheres, but the introduction of surfactants may have unpredictable effects on catalysis. [56] Therefore, here we used hexamethyldisilazane (HMDS) [57] instead to irreversibly hydrophobize the SiO 2 −NH 2 silica spheres (Scheme 2 a). The hydrophobization was confirmed in the IR spectrum by the intense C−H stretch and C−H bending vibrations of the grafted methyl groups around 2800 cm −1 and 1400 cm −1 (Figure S1b).…”

Section: Resultsmentioning

confidence: 99%

Bifunctional Janus Silica Spheres for Pickering Interfacial Tandem Catalysis

et al. 2021

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Nature provides much inspiration for the design of multistep conversion processes, with numerous reactions running simultaneously and without interference in cells, for example. A key challenge in mimicking nature's strategies is to compartmentalize incompatible reagents and catalysts, for example, for tandem catalysis. Here, we present a new strategy for antagonistic catalyst compartmentalization. The synthesis of bifunctional Janus catalyst particles carrying acid and base groups on the particle's opposite patches is reported as is their application as acid‐base catalysts in oil/water emulsions. The synthesis strategy involved the use of monodisperse, hydrophobic and amine‐functionalized silica particles (SiO2−NH2−OSi(CH3)3) to prepare an oil‐in‐water Pickering emulsion (PE) with molten paraffin wax. After solidification, the exposed patch of the silica particles was selectively etched and refunctionalized with acid groups to yield acid‐base Janus particles (Janus A–B). These materials were successfully applied in biphasic Pickering interfacial catalysis for the tandem dehydration‐Knoevenagel condensation of fructose to 5‐(hydroxymethyl)furfural‐2‐diethylmalonate (5‐HMF‐DEM) in a water/4‐propylguaiacol PE. The results demonstrate the advantage of rapid extraction of 5‐hydroxymethylfurfural (5‐HMF), a prominent platform molecule prone to side product formation in acidic media. A simple strategy to tune the acid/base balance using PE with both Janus A–B and monofunctional SiO2−NH2−OSi(CH3)3 base catalysts proved effective for antagonistic tandem catalysis.

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Section: Resultsmentioning

confidence: 99%

Bifunctional Janus Silica Spheres for Pickering Interfacial Tandem Catalysis

et al. 2021

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“…Similar problems are often analyzed with fluorescence microscopy; however, this requires the addition of staining chemicals or labeling steps [29][30][31]. For the selection of appropriate labels, making assumptions about the resulting particles is necessary.…”

Section: Discussionmentioning

confidence: 99%

“…We found that 3D-CRM is indispensable for the assignment of the different chemical entities to the morphological features on the particles, and distribution of chemical species can be visualized using PCA. Similar problems are often analyzed with fluorescence microscopy; however, this requires the addition of staining chemicals or labeling steps [ 29 , 30 , 31 ]. For the selection of appropriate labels, making assumptions about the resulting particles is necessary.…”

Section: Discussionmentioning

confidence: 99%

“…Depth profiles and 3D images can be created with exceptionally good spectral and spatial resolution [ 28 ], and the chemical properties can be analyzed with high spatial resolution close to the diffraction limit of light. The 3D-CRM technique is non-invasive, non-destructive, and does not require any complex sample preparation such as staining or labeling [ 29 , 30 , 31 , 32 , 33 , 34 ]. Since no interference with vibrational bands from water is observed, the particles can be examined directly from aqueous solution.…”

Section: Introductionmentioning

confidence: 99%

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Chemical Imaging of Single Anisotropic Polystyrene/Poly (Methacrylate) Microspheres with Complex Hierarchical Architecture

Wagner

Bredfeldt

et al. 2021

Polymers

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Monodisperse polystyrene spheres are functional materials with interesting properties, such as high cohesion strength, strong adsorptivity, and surface reactivity. They have shown a high application value in biomedicine, information engineering, chromatographic fillers, supercapacitor electrode materials, and other fields. To fully understand and tailor particle synthesis, the methods for characterization of their complex 3D morphological features need to be further explored. Here we present a chemical imaging study based on three-dimensional confocal Raman microscopy (3D-CRM), scanning electron microscopy (SEM), focused ion beam (FIB), diffuse reflectance infrared Fourier transform (DRIFT), and nuclear magnetic resonance (NMR) spectroscopy for individual porous swollen polystyrene/poly (glycidyl methacrylate-co-ethylene di-methacrylate) particles. Polystyrene particles were synthesized with different co-existing chemical entities, which could be identified and assigned to distinct regions of the same particle. The porosity was studied by a combination of SEM and FIB. Images of milled particles indicated a comparable porosity on the surface and in the bulk. The combination of standard analytical techniques such as DRIFT and NMR spectroscopies yielded new insights into the inner structure and chemical composition of these particles. This knowledge supports the further development of particle synthesis and the design of new strategies to prepare particles with complex hierarchical architectures.

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“…Thus, particle properties have an important effect on the stability of Pickering emulsions. One of the most frequently used methods to adjust particle properties is chemical modification. − For example, Wei et al and Zhang et al . grafted trimethoxysilyl groups to the surface of SiO 2 and TiO 2 nanoparticles, respectively, making those particles more hydrophobic.…”

Section: Introductionmentioning

confidence: 99%

Enzyme Anchoring Amphiphilic Polymer Nanoparticles for Enhanced Pickering Interfacial Biocatalysis

Tian

Zhang

Yan³

et al. 2023

ACS Appl. Polym. Mater.

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Pickering interfacial biocatalysis has been attracting much attention from researchers as the chemical industry needs to become cleaner and more efficient.The key to Pickering interfacial biocatalysis is the preparation of enzyme-loaded particles, which usually involves the modification and functionalization of particles. Although many studies have been reported, the complex modification and functionalization processes involved in these works hinder their application. Herein, we use a one-step method to generate polymer nanoparticles with innate carboxyl functional groups. The wettability of these nanoparticles can be easily adjusted by changing the composition of the polymer. In addition, the enzymes immobilized on nanoparticles show excellent reusability and storage stability with limited activity loss during the immobilization process. When enzyme-loaded nanoparticles were applied to Pickering interfacial biocatalysis, the initial reaction rate could be increased to 2.4fold that of pristine organic−aqueous biphasic reactions. Furthermore, the small-scale continuous Pickering interfacial biocatalysis sheds some light on the applications of these polymer nanoparticles.

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Controllable synthesis of patchy particles with tunable geometry and orthogonal chemistry

Cited by 15 publications

References 49 publications

Bifunctional Janus Silica Spheres for Pickering Interfacial Tandem Catalysis

Bifunctional Janus Silica Spheres for Pickering Interfacial Tandem Catalysis

Chemical Imaging of Single Anisotropic Polystyrene/Poly (Methacrylate) Microspheres with Complex Hierarchical Architecture

Enzyme Anchoring Amphiphilic Polymer Nanoparticles for Enhanced Pickering Interfacial Biocatalysis

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