scholarly journals Harnessing nonlinear rubber swelling for bulk synthesis of anisotropic hybrid nanoparticles

2014 ◽  
Vol 2 (41) ◽  
pp. 8745-8749 ◽  
Author(s):  
Tao Ding ◽  
Stoyan K. Smoukov ◽  
Jeremy J. Baumberg

Facile, scalable synthesis of monodisperse anisotropic hybrid nanoparticles (Au nanospheres/nanorod cores and poly(divinyl benzene) shell). Mechanism is based on nonlinear swelling of the polymer during a seeded polymerization process.

2005 ◽  
Vol 38 (10) ◽  
pp. 4183-4192 ◽  
Author(s):  
Mei Li ◽  
Eric S. Daniels ◽  
Victoria Dimonie ◽  
E. David Sudol ◽  
Mohamed S. El-Aasser

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 373
Author(s):  
Adolfo Sepúlveda ◽  
Audrey Picard-Lafond ◽  
André Marette ◽  
Denis Boudreau

The implementation of gold-hydrogel core-shell nanomaterials in novel light-driven technologies requires the development of well-controlled and scalable synthesis protocols with precisely tunable properties. Herein, new insights are presented concerning the importance of using the concentration of gold cores as a control parameter in the seeded precipitation polymerization process to modulate—regardless of core size—relevant fabrication parameters such as encapsulation yield, particle size and shrinkage capacity. Controlling the number of nucleation points results in the facile tuning of the encapsulation process, with yields reaching 99% of gold cores even when using different core sizes at a given particle concentration. This demonstration is extended to the encapsulation of bimodal gold core mixtures with equally precise control on the encapsulation yield, suggesting that this principle could be extended to encapsulating cores composed of other materials. These findings could have a significant impact on the development of stimuli-responsive smart materials.


2004 ◽  
Vol 847 ◽  
Author(s):  
Etienne Duguet ◽  
Stéphane Reculusa ◽  
Adeline Perro ◽  
Céline Poncet-Legrand ◽  
Serge Ravaine ◽  
...  

ABSTRACTColloidal particles with a controlled morphology combining both organic and inorganic parts were synthesized through a seeded emulsion polymerization process. Silica seed particles (from 50 to 150 nm in diameter) were first surface-modified by the adsorption of an oxyethylene-based macromonomer. Then, emulsion polymerization of styrene was carried out in presence of these particles, the formation of polystyrene nodules being highly favored at the silica surface in such conditions. The ratio between the number of silica seeds and the number of growing polystyrene nodules appeared to be one of the key parameters to control the morphology of the final hybrid nanoparticles. When this ratio is close to 1, original hybrid dumbbell-like nanoparticles were mainly obtained.


2008 ◽  
Vol 2008 ◽  
pp. 1-8 ◽  
Author(s):  
Jean-Christophe Daigle ◽  
Jerome P. Claverie

Core-shell hybrid nanoparticles, where the core is an inorganic nanoparticle and the shell an organic polymer, are prepared by a two-step method. Inorganic nanoparticles are first dispersed in water using poly(acrylic acid) (PAA) prepared by reversible addition fragmentation chain transfer (RAFT) polymerization as dispersant. Then, the resulting dispersion is engaged in a radical emulsion polymerization process whereby a hydrophobic organic monomer (styrene and butyl acrylate) is polymerized to form the shell of the hybrid nanoparticle. This method is extremely versatile, allowing the preparation of a variety of nanocomposites with metal oxides (alumina, rutile, anatase, barium titanate, zirconia, copper oxide), metals (Mo, Zn), and even inorganic nitrides (Si3N4).


1974 ◽  
Vol 31 (02) ◽  
pp. 309-318
Author(s):  
Phyllis S Roberts ◽  
Raphael M Ottenbrite ◽  
Patricia B Fleming ◽  
James Wigand

Summary1. Choline chloride, 0.1 M (in 0.25 M Tris. HCl buffer, pH 7.4 or 8.0, 37°), doubles the rate of hydrolysis of TAME by bovine thrombokinase but has no effect on the hydrolysis of this ester by either human or bovine thrombin. Only when 1.0 M or more choline chloride is present is the hydrolysis of BAME by thrombokinase or thrombin weakly inhibited. Evidence is presented that shows that these effects are due to the quaternary amine group.2. Tetramethyl ammonium bromide or chloride has about the same effects on the hydrolysis of esters by these enzymes as does choline chloride but tetra-ethyl, -n.propyl and -n.butyl ammonium bromides (0.1 M) are stronger accelerators of the thrombokinase-TAME reaction and they also accelerate, but to a lesser degree, the thrombin-TAME reaction. In addition, they inhibit the hydrolysis of BAME by both enzymes. Their effects on these reactions, however, do not follow any regular order. The tetraethyl compound is the strongest accelerator of the thrombokinase-TAME reaction but the tetra-ethyl and -butyl compounds are the strongest accelerators of the thrombin-TAME reaction. The ethyl and propyl compounds are the best (although weak) inhibitors of the thrombokinase-BAME and the propyl compound of the thrombin-BAME reactions.3. Tetra-methyl, -ethyl, -n.propyl and -n.butyl ammonium bromides (0.01 M) inhibit the clotting of fibrinogen by thrombin (bovine and human proteins) at pH 7.4, imidazole or pH 6.1, phosphate buffers and they also inhibit, but to a lesser degree, a modified one-stage prothrombin test. In all cases the inhibition increases regularly as the size of the alkyl group increases from methyl to butyl. Only the ethyl com pound (0.025 M but not 0.01 M), however, significantly inhibits the polymerization of bovine fibrin monomers. It was concluded that inhibition of the fibrinogen-thrombin and the one-stage tests by the quaternary amines is not due to any effect of the com pounds on the polymerization process but probably due to inhibition of thrombin’s action on fibrinogen by the quaternary amines.


2019 ◽  
Author(s):  
Merlin Kleoff ◽  
Johannes Schwan ◽  
Lisa Boeser ◽  
Bence Hartmayer ◽  
Mathias Christmann ◽  
...  

A scalable access to functionalized 1,1’- and 1,2-ferrocenyl azides has been realized in flow. By halogen‒lithium exchange of ferrocenyl halides and subsequent reaction with tosyl azide, a variety of functionalized ferrocenyl azides was obtained in high yields. To allow a scalable preparation of these potentially explosive compounds, an efficient flow protocol was developed accelerating the reaction time to minutes and circumventing accumulation of potentially hazardous intermediates. Switching from homogeneous to triphasic flow amidst process was key for handling a heterogeneous reaction mixture formed after a heated reactor section. The corresponding and synthetically versatile ferrocenyl amines were then prepared by a reliable reduction process.


Author(s):  
Жанна Владимировна Вечеркина ◽  
Наталия Владимировна Чиркова ◽  
Михаил Анатольевич Крючков ◽  
Виктор Сергеевич Калиниченко

Развитие технологий, основанных на использовании низкотоксичных материалов, позволит в скором будущем начать их применение в медицине. Применение наночастиц серебра, меди, кремния, цинка, титана, кобальта в качестве модифицирующей добавки позволит оказать активное влияние на структуру исходных материалов и изменение их свойств, а именно улучшение физико-механических, физико-химических и токсико-гигиенических свойств материалов. Наноразмерные частицы кремния, введенные в фиксирующие стоматологические материалы, приводят к улучшению физико-химических, физико-механических свойств кристаллизующихся материалов, а малая теплопроводность кремния может увеличить его рабочее время и снизить выделение тепла при реакции кристаллизации. Так как от этих характеристик зависит объем манипуляций, при фиксации ортопедических конструкций на опорных зубах целесообразно было бы привести рабочее время твердения к чистому времени твердения, что позволит увеличить объем манипуляций приготовленной массой без ухудшения ее свойств. Разработка высокопрочных, биосовместимых, высокотехнологичных нанопластмасс для базисов съемных пластиночных протезов является актуальной проблемой повышения качества жизни пациентов. Модификация наноразмерными частицами серебра, кремния акрилового полимера позволит улучшить такие физико-механические свойства, как ударную вязкость, прочность, температуростойкость, барьерные свойства, уменьшить усадку полимера на этапе полимеризации, в отличие от уже известных отечественных и дорогостоящих импортных полимеров. Наноразмерные частицы кремния, серебра являются сокатализаторами метилметакрилата, влияющими на уменьшение количества остаточного мономера после процесса полимеризации, тем самым повышая санитарно-химические и токсико-гигиенические характеристики полимера. Все вышеизложенное позволило сформулировать цель исследований по наноструктурированным материалам под руководством профессора …посвящается памяти профессора, д.м.н. Каливраджияна Э.С. The development of technologies based on the use of low-toxic materials will make it possible to begin their application in medicine in the near future. The use of nanoparticles of silver, copper, silicon, zinc, titanium, cobalt as a modifying additive will make it possible to actively influence the structure of the starting materials and change their properties, namely, improve the physicomechanical, physicochemical and toxicohygienic properties of materials. Nanosized silicon particles introduced into fixing dental materials lead to an improvement in the physicochemical, physicomechanical properties of crystallizing materials, and the low thermal conductivity of silicon can increase its working time and reduce heat generation during the crystallization reaction. Since the volume of manipulations depends on these characteristics, when fixing orthopedic structures on abutment teeth, it would be advisable to bring the working time of hardening to a pure hardening time, which will increase the volume of manipulations with the prepared mass without deteriorating its properties. The development of high-strength, biocompatible, high-tech nanoplastics for the bases of removable plate prostheses is an urgent problem to improve the quality of life of patients. Modification of acrylic polymer with nano-sized particles of silver and silicon will improve such physical and mechanical properties as impact strength, strength, temperature resistance, barrier properties, and reduce polymer shrinkage at the stage of polymerization, in contrast to the already known domestic and expensive imported polymers. Nanosized particles of silicon, silver are cocatalysts of methyl methacrylate, affecting the reduction of the amount of residual monomer after the polymerization process, thereby increasing the sanitary-chemical and toxic-hygienic characteristics of the polymer. All of the above made it possible to formulate the goal of research on nanostructured materials under the guidance of the professor …dedicated to the memory of the professor, d.m.s. Kalivrajiyan E.S.


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