Simultaneous control of size and surface functionality of silica particle via growing method

2017 ◽  
Vol 28 (11) ◽  
pp. 2914-2920 ◽  
Author(s):  
Seongjun Moon ◽  
Kyung Jin Lee
Keyword(s):  
Silica Particle ◽  
Surface Functionality ◽  
Simultaneous Control

Reactive Nanopattern in a Triple Structured Bio-Inspired Honeycomb Film as a Clickable Platform

2018 ◽  
Author(s):  
Pierre Marcasuzaa ◽  
Samuel Pearson ◽  
Karell Bosson ◽  
Laurence Pessoni ◽  
Jean-Charles Dupin ◽  
...  
Keyword(s):  
Self Assembly ◽  
Double Porosity ◽  
Surface Groups ◽  
Specific Chemical ◽  
Site Specific ◽  
Surface Functionality ◽  
Wenzel State ◽  
Breath Figure ◽  
Responsive Surfaces ◽  
Secondary Population

A hierarchically structured platform was obtained from spontaneous self-assembly of a poly(styrene)-<i>b</i>-poly(vinylbenzylchloride) (PS-<i>b</i>-PVBC) block copolymer (BCP) during breath figure (BF) templating. The BF process using a water/ethanol atmosphere gave a unique double porosity in which hexagonally arranged micron-sized pores were encircled by a secondary population of smaller, nano-sized pores. A third level of structuration was simultaneously introduced between the pores by directed BCP self-assembly to form out-of-the-plane nano-cylinders, offering very rapid bottom-up access to a film with unprecedented triple structure which could be used as a reactive platform for introducing further surface functionality. The surface nano-domains of VBC were exploited as reactive nano-patterns for site-specific chemical functionalization by firstly substituting the exposed chlorine moiety with azide, then “clicking” an alkyne by copper (I) catalyzed azide-alkyne Huisgen cycloaddition (CuAAC). Successful chemical modification was verified by NMR spectroscopy, FTIR spectroscopy, and XPS, with retention of the micro- and nanostructuration confirmed by SEM and AFM respectively. Protonation of the cyclotriazole surface groups triggered a switch in macroscopic behavior from a Cassie-Baxter state to a Wenzel state, highlighting the possibility of producing responsive surfaces with hierarchical structure.

Flow Chemistry Controls Both Self-Assembly and the Entrapped Oscillatory Cargo in Belousov-Zhabotinsky Driven Polymerization-Induced Self-Assembly

2019 ◽  
Author(s):  
Liman Hou ◽  
Marta Dueñas-Diez ◽  
Rohit Srivastava ◽  
Juan Perez-Mercader
Keyword(s):  
Self Assembly ◽  
Flow Chemistry ◽  
Batch Reactors ◽  
Equilibrium Conditions ◽  
One Pot ◽  
Bz Reaction ◽  
Polymer Vesicles ◽  
Simultaneous Control ◽  
Novel Method ◽  
Continuously Stirred Tank Reactor

<p></p><p>Belousov-Zhabotinsky (B-Z) reaction driven polymerization-induced self-assembly (PISA), or B-Z PISA, is a novel method for the autonomous one-pot synthesis of polymer vesicles from a macroCTA (macro chain transfer agent) and monomer solution (“soup”) containing the above and the BZ reaction components. In it, the polymerization is driven (and controlled) by periodically generated radicals generated in the oscillations of the B-Z reaction. These are inhibitor/activator radicals for the polymerization. Until now B-Z PISA has only been carried out in batch reactors. In this manuscript we present the results of running the system using a continuously stirred tank reactor (CSTR) configuration which offers some interesting advantages.Indeed, by controlling the CSTR parameters we achieve reproducible and simultaneous control of the PISA process and of the properties of the oscillatory cargo encapsulated in the resulting vesicles. Furthermore, the use of flow chemistry enables a more precise morphology control and chemical cargo tuning. Finally, in the context of biomimetic applications a CSTR operation mimics more closely the open non-equilibrium conditions of living systems and their surrounding environments.</p><p></p>

Ultrafiltration of silica sols

1989 ◽  
Vol 54 (1) ◽  
pp. 91-101 ◽  
Author(s):  
Milan Stakić ◽  
Slobodan Milonjić ◽  
Vladeta Pavasović ◽  
Zoja Ilić
Keyword(s):  
Particle Size ◽  
Silica Particle ◽  
Specific Resistance ◽  
Membrane Surface ◽  
Membrane Resistance ◽  
Experimental Conditions ◽  
Surface Unit ◽  
Silica Sols ◽  
Filtration Flux ◽  
Batch Cell

Ultrafiltration of three laboratory made silica and two commercial silica sols was studied using Amicon YC membrane in a 200 ml capacity batch-cell. The effect of silica particle size, stirring conditions, pressure, pH and silica contents on ultrafiltration was investigated. The results obtained indicate that the smaller particles have, disregarding the stirring conditions, lower filtration flux. The differences observed in filtration flux are more pronounced in the conditions without stirring. The obtained value of the membrane resistance is independent of the conditions investigated (stirring, pressure, pH, silica contents and particle size). The values of the resistance of polarized solids, specific resistance, and the mass of gel per membrane surface unit were calculated for all experimental conditions.

Surface functionality and porosity of activated carbons obtained from chemical activation of wood

Carbon ◽  
2000 ◽  
Vol 38 (5) ◽  
pp. 669-674 ◽  
Author(s):  
H Benaddi ◽  
T.J Bandosz ◽  
J Jagiello ◽  
J.A Schwarz ◽  
J.N Rouzaud ◽  
...  
Keyword(s):  
Activated Carbons ◽  
Chemical Activation ◽  
Surface Functionality

scholarly journals Spherical silica particle production by combined biomimetic-Stöber synthesis using renewable sodium caseinate without petrochemical agents

2021 ◽  
Vol 11 (4) ◽  
pp. 1151-1167
Author(s):  
Ricky Curley ◽  
Russell A. Banta ◽  
Shane Garvey ◽  
Justin D. Holmes ◽  
Eoin J. Flynn
Keyword(s):  
Silica Particle ◽  
Particle Production ◽  
Sodium Caseinate ◽  
Spherical Silica ◽  
Spherical Silica Particle

scholarly journals Synthesis and Characterization of a Fullerenol Derivative for Potential Biological Applications

2020 ◽  
Vol 4 (1) ◽  
pp. 15
Author(s):  
Eduardo Ravelo-Nieto ◽  
Alvaro Duarte-Ruiz ◽  
Luis H. Reyes ◽  
Juan C. Cruz
Keyword(s):  
Phase Transfer ◽  
Protein A ◽  
Structural Features ◽  
Cellular Level ◽  
Cellulose Membrane ◽  
Cell Penetration ◽  
Covalent Functionalization ◽  
Dialysis Tubing ◽  
Surface Functionality

Several biological barriers are generally responsible for the limited delivery of cargoes at the cellular level. Fullerenols have unique structural features and possess suitable properties for interaction with the cells. This study aimed to synthesize and characterize a fullerenol derivative with desirable characteristics (size, charge, functionality) to develop cell penetration vehicles. Fullerenol was synthesized from fullerene (C60) solubilized in toluene, followed by hydroxylation with hydrogen peroxide and tetra-n-butylammonium hydroxide (TBAH) as a phase transfer catalyst. The obtained product was purified by a Florisil chromatography column (water as the eluent), followed by dialysis (cellulose membrane dialysis tubing) and freeze-drying (yield 66%). Subsequently, a silane coupling agent was conjugated on the fullerenol surface to render free amine functional groups for further covalent functionalization with other molecules. Characterization via UV–VIS, FTIR-ATR, Raman, DLS, and SEM techniques was conducted to evaluate the composition, size, morphology, surface functionality, and structural properties. We are currently working on the conjugation of the potent cell-penetrating agents Buforin II (BUFII) and the Outer Membrane Protein A (OmpA) on the surface of the fullerenol to estimate whether cell penetration and endosome escape are improved concerning conventional polymeric vehicles and our previous developments with iron oxide nanoparticles.

Biochar Surface Functionality Plays a Vital Role in (Im)Mobilization and Phytoavailability of Soil Vanadium

2021 ◽  
Author(s):  
Ali El-Naggar ◽  
Sabry M. Shaheen ◽  
Scott X. Chang ◽  
Deyi Hou ◽  
Yong Sik Ok ◽  
...  
Keyword(s):  
Vital Role ◽  
Surface Functionality

scholarly journals A Survey on Machine-Learning Based Security Design for Cyber-Physical Systems

2021 ◽  
Vol 11 (12) ◽  
pp. 5458
Author(s):  
Sangjun Kim ◽  
Kyung-Joon Park
Keyword(s):  
Machine Learning ◽  
Physical System ◽  
Large Scale ◽  
Computing System ◽  
Future Research ◽  
Physical Security ◽  
Computing Systems ◽  
Physical Systems ◽  
Security Research ◽  
Simultaneous Control

A cyber-physical system (CPS) is the integration of a physical system into the real world and control applications in a computing system, interacting through a communications network. Network technology connecting physical systems and computing systems enables the simultaneous control of many physical systems and provides intelligent applications for them. However, enhancing connectivity leads to extended attack vectors in which attackers can trespass on the network and launch cyber-physical attacks, remotely disrupting the CPS. Therefore, extensive studies into cyber-physical security are being conducted in various domains, such as physical, network, and computing systems. Moreover, large-scale and complex CPSs make it difficult to analyze and detect cyber-physical attacks, and thus, machine learning (ML) techniques have recently been adopted for cyber-physical security. In this survey, we provide an extensive review of the threats and ML-based security designs for CPSs. First, we present a CPS structure that classifies the functions of the CPS into three layers: the physical system, the network, and software applications. Then, we discuss the taxonomy of cyber-physical attacks on each layer, and in particular, we analyze attacks based on the dynamics of the physical system. We review existing studies on detecting cyber-physical attacks with various ML techniques from the perspectives of the physical system, the network, and the computing system. Furthermore, we discuss future research directions for ML-based cyber-physical security research in the context of real-time constraints, resiliency, and dataset generation to learn about the possible attacks.

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