scholarly journals Surface-Induced ARGET ATRP for Silicon Nanoparticles with Fluorescent Polymer Brushes

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1228 ◽  
Author(s):  
Chun-Na Yan ◽  
Lin Xu ◽  
Qing-Di Liu ◽  
Wei Zhang ◽  
Rui Jia ◽  
...  
Keyword(s):  
Silica Nanoparticles ◽  
Hybrid Materials ◽  
Rhodamine B ◽  
Methyl Acrylate ◽  
Polymer Brushes ◽  
Diblock Copolymers ◽  
Polymerization Process ◽  
Good Dispersion ◽  
Fluorescence Characteristics ◽  
Arget Atrp

Well-defined polymer brushes attached to nanoparticles offer an elegant opportunity for surface modification because of their excellent mechanical stability, functional versatility, high graft density as well as controllability of surface properties. This study aimed to prepare hybrid materials with good dispersion in different solvents, and to endow this material with certain fluorescence characteristics. Well-defined diblock copolymers poly (styrene)-b-poly (hydroxyethyl methyl acrylate)–co-poly (hydroxyethyl methyl acrylate- rhodamine B) grafted silica nanoparticles (SNPs-g-PS-b-PHEMA-co-PHEMA-RhB) hybrid materials were synthesized via surface-initiated activators regenerated by electron transfer atom transfer radical polymerization (SI-ARGET ATRP). The SNPs surfaces were modified by 3-aminopropyltriethoxysilane (KH-550) firstly, then the initiators 2-Bromoisobutyryl bromide (BIBB) was attached to SNPs surfaces through the esterification of acyl bromide groups and amidogen groups. The synthetic initiators (SNPs-Br) were further used for the SI-ARGET ATRP of styrene (St), hydroxyethyl methyl acrylate (HEMA) and hydroxyethyl methyl acrylate-rhodamine B (HEMA-RhB). The results indicated that the SI-ARGET ATRP initiator had been immobilized onto SNPs surfaces, the Br atom have located at the end of the main polymer chains, and the polymerization process possessed the characteristic of controlled/“living” polymerization. The SNPs-g-PS-b-PHEMA-co-PHEMA-RhB hybrid materials show good fluorescence performance and good dispersion in water and EtOH but aggregated in THF. This study demonstrates that the SI-ARGET ATRP provided a unique way to tune the polymer brushes structure on silica nanoparticles surface and further broaden the application of SI-ARGET ATRP.

Multi-Stimuli-Responsive Mesoporous Membranes and Effect of Molecular Architecture on Thermo- and pH-Responsive Behavior of the grafted Block Copolymer brushes

2019 ◽  
Author(s):  
Yanchun Tang ◽  
Kohzo Ito ◽  
Hideaki Yokoyama
Keyword(s):  
Polymer Brushes ◽  
Diblock Copolymers ◽  
Neutron Reflectivity ◽  
Molecular Architecture ◽  
Stimuli Responsive ◽  
Responsive Polymer ◽  
The Matrix ◽  
Stable Part ◽  
Copolymer Brushes ◽  
Mesoporous Membranes

In this study, we prepared ultrafiltration membranes with a decoupled responses of filtration property to temperature and pH. The membrane preparation method was developed based on our previous work. We utilized methanol-supercritical carbon dioxide (methanol-scCO<sub>2</sub>) selective swelling method to introduce nanopores to block copolymers containing poly(diethylene glycol) methyl ether methacrylate (PMEO<sub>2</sub>MA), poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) and polystyrene (PS) blocks. Formation of the mesoporous barrier layer with PS being the mechanically stable part of the matrix was driven by selective swelling of the PMEO<sub>2</sub>MA-b-PDMAEMA domains. Due to the selective swelling of PMEO<sub>2</sub>MA or PDMAEMA domains to introduce pores, the interior of the pores are covered with PMEO<sub>2</sub>MA or PDMAEMA blocks after pore formation. The PMEO<sub>2</sub>MA-b-PDMAEMA polymer brushes are naturally attached on the pore walls and worked as functional gates. PMEO<sub>2</sub>MA is a non-toxic, neutral thermo-responsive polymer with LCST at 26 ᴼC. PDMAEMA is a typical weak polyelectrolyte with pK<sub>a</sub> value at 7.0-7.5 and also a thermo-responsive polymer revealed a LCST of 20-80 °C in aqueous solution. Therefore, these membranes were expected to have multi dimensions as function of the combination of temperature and pH. Moreover, to understand the detail of the temperature and pH depended conformation transitions of PMEO<sub>2</sub>MA-b-PDMAEMA brushes, those diblock copolymers were end-tethered on flat substrates and analyzed via neutron reflectivity (NR).

scholarly journals Self-restoring polymer brushes under tribological stress and the biomedical applications

MRS Advances ◽  
2016 ◽  
Vol 1 (27) ◽  
pp. 1971-1976
Author(s):  
Troels Røn ◽  
Irakli Javakhishvili ◽  
Søren Hvilsted ◽  
Katja Jankova ◽  
Seunghwan Lee
Keyword(s):  
Polymer Brushes ◽  
Diblock Copolymers ◽  
Polymer Chains ◽  
Aqueous Environment ◽  
Pdms Film ◽  
Pdms Surface ◽  
Tribological Application ◽  
Optimal Functions ◽  
Amphiphilic Diblock Copolymers

ABSTRACTFor biological and mechanical systems involving moving parts, surface slipperiness is often a critical attribute for their optimal functions. Surface grafting with hydrophilic polymers is a powerful means to render materials slippery in aqueous environment. In “inverted grafting-to approach”, the hydrophilic polymer chains of amphiphilic diblock copolymers dispersed within a poly(dimethylsiloxane) (PDMS) network are selectively segregated upon exposure to aqueous solution. This allows formation of extremely stable brush-like polymer layers. Tribological application of inverted grafting-to approach was successfully demonstrated with PDMS-block-poly(acrylic acid) (PDMS-b-PAA) dispersed within thin PDMS films on PDMS blocks by showing friction coefficients (µ) of ca 10-2 to 10-3, depending on the load, pH and buffer salinity in the absence of other external re-supply of PAA chains. Further manipulations of the thin PDMS film incorporating PDMS-b-PAA to optimize the tribological properties are presented. Lastly, first trials to employ PAA-grafted PDMS surface to generate in-vitro mucosae model are also presented and discussed.

The Effect of Chain Length on Polyelectrolyte Brushes Formed from Adsorption of Diblock Copolymers

2013 ◽  
Vol 800 ◽  
pp. 428-431
Author(s):  
Yang Yang ◽  
Chun Cheng Zuo ◽  
Yu Xin Zuo ◽  
Ying Yu
Keyword(s):  
Chain Length ◽  
Polymer Brushes ◽  
Diblock Copolymers ◽  
Positive Charge ◽  
Surface Adsorption ◽  
Crystal Surfaces ◽  
Dynamic Simulations ◽  
Polyelectrolyte Brushes ◽  
Adsorption Density ◽  
Copolymer Brushes

The formation process of diblock copolymer brushes, formed by the adsorption of flexible chains on the surface is studied by Molecular Dynamic simulations. The surface adsorption density has been distinguished, depending on the various chain structures and counterions. The mode was considered as size ratio of A-block lengths to the the chain length, B-block carries the positive charge, and add counterions to the system. The result shows that the surface adsorption density is affected strongly by ratio of A-block length to the chain length, inhibited by the counterions, which is qualitatively consistent with experiments. These initial findings can be used as a guide for the preparation of actual diblock polymer brushes on metal crystal surfaces membranes by the adsorption approach.

Preparation of Polymer Brushes by Surface-Initiated ARGET ATRP

2013 ◽  
Vol 791-793 ◽  
pp. 208-211 ◽  
Author(s):  
Xiao Meng Chu ◽  
Shao Jie Liu ◽  
Hui Jiao Yang ◽  
Feng Qing Zhao
Keyword(s):  
Molecular Weight ◽  
Silicon Dioxide ◽  
Polymer Brushes ◽  
Polymer Brush ◽  
Surface Modifications ◽  
Organic Substrate ◽  
Research Progress ◽  
Grafting Density ◽  
Arget Atrp ◽  
Inorganic Substrate

This paper firstly summarized the latest research progress on the polymer brushes preparation by surface-initiated ARGET ATRP polymerization. It mainly includes the surface modifications of inorganic substrate (silicon dioxide and carbon nanotubes), and the organic substrate (cellulose and polymer microspheres). This method needs less catalyst and operates more easily, compared to the classical ATRP. Besides, it also has good polymerization controllability, and the polymer brushes have higher grafting density and molecular weight. Therefore, surface-initiated ARGET ATRP polymerization has become an effective method for modifying the surface of materials. Then, we prepared the polymer brush supported TEMPO by the surface-initiated ARGET ATRP and characterized.

Synthesis of large-pore SBA-15 silica using poly(ethylene oxide)-poly(methyl acrylate) diblock copolymers

Adsorption ◽  
2009 ◽  
Vol 15 (2) ◽  
pp. 156-166 ◽  
Author(s):  
Liang Cao ◽  
Hongchen Dong ◽  
Liang Huang ◽  
Krzysztof Matyjaszewski ◽  
Michal Kruk
Keyword(s):  
Ethylene Oxide ◽  
Methyl Acrylate ◽  
Diblock Copolymers ◽  
Large Pore ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

Formation of Polymer Brushes with Diblock Copolymers on a Planar Surface

2013 ◽  
Vol 705 ◽  
pp. 143-149 ◽  
Author(s):  
Yang Yang ◽  
Chun Cheng Zuo ◽  
Yu Xin Zuo ◽  
Ying Yu
Keyword(s):  
Polymer Brushes ◽  
Diblock Copolymers ◽  
Physical Adsorption ◽  
Surface Adsorption ◽  
Length Ratio ◽  
Planar Surface ◽  
Fixed Length ◽  
Adsorption Density ◽  
Dynamics Simulations ◽  
Behavior Characteristics

We use molecular dynamics simulations method to investigate the behavior characteristics of AB diblock copolymers that are adsorbed on a planar surface. Adsorption density has been distinguished, depending on the adsorption manner of A-block on the (100) surface and formation of brushes. It is examined in detail that conformational behavior of the brushes affects the adsorption density. In addition, we make a comparison of linear brush with length ratio of the A-block to the chain, in the cases of the fixed length of chain and the fixed length of A-block, respectively. The result shows that the adsorption density is strongly affected by the length ratio of the A-block to the chain. And our findings can be used as a guide for fabrication and preparation of actual synthetic polymer brushes on a solid surface by the approach of physical adsorption.

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