Reversible sol–gel transitions of aqueous dispersions of silica nanoparticles grafted with diblock copolymer brushes composed of a thermosensitive inner block and a charged outer block

Soft Matter ◽  
2015 ◽  
Vol 11 (34) ◽  
pp. 6808-6820 ◽  
Author(s):  
Roger A. E. Wright ◽  
Bin Hu ◽  
Daniel M. Henn ◽  
Bin Zhao
Keyword(s):  
Silica Nanoparticles ◽  
Diblock Copolymer ◽  
Sol Gel ◽  
Aqueous Dispersions ◽  
Copolymer Brushes

scholarly journals Selective porous gates made from colloidal silica nanoparticles

2015 ◽  
Vol 6 ◽  
pp. 2105-2112 ◽  
Author(s):  
Roberto Nisticò ◽  
Paola Avetta ◽  
Paola Calza ◽  
Debora Fabbri ◽  
Giuliana Magnacca ◽  
...  
Keyword(s):  
Silica Nanoparticles ◽  
Spin Coating ◽  
Colloidal Silica ◽  
Sol Gel ◽  
Chemical Species ◽  
Solvent System ◽  
Porous Films ◽  
Nanoporous Films ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene

Highly selective porous films were prepared by spin-coating deposition of colloidal silica nanoparticles on an appropriate macroporous substrate. Silica nanoparticles very homogenous in size were obtained by sol–gel reaction of a metal oxide silica precursor, tetraethyl orthosilicate (TEOS), and using polystyrene-block-poly(ethylene oxide) (PS-b-PEO) copolymers as soft-templating agents. Nanoparticles synthesis was carried out in a mixed solvent system. After spin-coating onto a macroporous silicon nitride support, silica nanoparticles were calcined under controlled conditions. An organized nanoporous layer was obtained characterized by a depth filter-like structure with internal porosity due to interparticle voids. Permeability and size-selectivity were studied by monitoring the diffusion of probe molecules under standard conditions and under the application of an external stimulus (i.e., electric field). Promising results were obtained, suggesting possible applications of these nanoporous films as selective gates for controlled transport of chemical species in solution.

Ordered Diblock Copolymer Films on Random Copolymer Brushes

1997 ◽  
Vol 30 (22) ◽  
pp. 6810-6813 ◽  
Author(s):  
P. Mansky ◽  
T. P. Russell ◽  
C. J. Hawker ◽  
M. Pitsikalis ◽  
J. Mays
Keyword(s):  
Diblock Copolymer ◽  
Random Copolymer ◽  
Copolymer Films ◽  
Copolymer Brushes

Natural Rubber Reinforced with Silica Nanoparticles Extracted from Jasmine and Riceberry Rice Husk Ashes

2018 ◽  
Vol 936 ◽  
pp. 31-36 ◽  
Author(s):  
Wichudaporn Seangyen ◽  
Paweena Prapainainar ◽  
Pongdhorn Sae-Oui ◽  
Surapich Loykulnant ◽  
Peerapan Dittanet
Keyword(s):  
Tensile Strength ◽  
Natural Rubber ◽  
Silica Nanoparticles ◽  
Rice Husk ◽  
Sol Gel ◽  
Rubber Matrix ◽  
Reinforcing Fillers ◽  
Rubber Nanocomposites ◽  
Jasmine Rice ◽  
20 Nm

Silica nanoparticles were synthesized by rice husk ash (RHA) produced from jasmine rice husk and riceberry rice husk via sol-gel method for the use as reinforcing fillers in natural rubber (NR). The obtained silica nanoparticles are spherical in shape and the particle sizes were observed to be in the 10-20 nm range with uniformly size distribution. The surface of silica nanoparticles was treated with a silane coupling agent confirmed by FTIR. The treated silica nanoparticles were then incorporated into NR and vulcanized with electron beam irradiation. The rubber nanocomposites with silica nanoparticles, produced from jasmine rice husk and riceberry rice husk, resulted in higher mechanical properties (tensile strength and modulus) than neat rubber vulcanizate. The modified rubber vulcanizates revealed rougher surface with tear lines as compared to the neat rubber vulcanizates, indicating the improved strength. Interestingly, the rubber nanocomposites with silica nanoparticles from jasmine rice husk showed higher tensile strength and modulus than silica nanoparticles produced from riceberry rice husk. The micrographs indicated better dispersion of NR composites with jasmine rice husk which leads to a strong interaction between silica nanoparticles and rubber matrix, thereby improving the strength.

Preparation of superhydrophobic silica nanoparticles by microwave assisted sol–gel process

2011 ◽  
Vol 61 (1) ◽  
pp. 8-13 ◽  
Author(s):  
A. Santiago ◽  
A. González ◽  
J. J. Iruin ◽  
M. J. Fernández-Berridi ◽  
L. Irusta
Keyword(s):  
Silica Nanoparticles ◽  
Sol Gel ◽  
Microwave Assisted ◽  
Sol Gel Process ◽  
Superhydrophobic Silica

Self-Assembled Morphologies of Diblock Copolymer Brushes in Poor Solvents

2012 ◽  
Vol 45 (11) ◽  
pp. 4920-4931 ◽  
Author(s):  
Run Jiang ◽  
Baohui Li ◽  
Zheng Wang ◽  
Yuhua Yin ◽  
An-Chang Shi
Keyword(s):  
Diblock Copolymer ◽  
Self Assembled ◽  
Copolymer Brushes

scholarly journals Hybrid Mesoporous Silica Nanoparticles Grafted with 2-(tert-butylamino)ethyl Methacrylate-b-poly(ethylene Glycol) Methyl Ether Methacrylate Diblock Brushes as Drug Nanocarrier

Molecules ◽  
2020 ◽  
Vol 25 (1) ◽  
pp. 195 ◽  
Author(s):  
Abdullah M Alswieleh ◽  
Abeer M Beagan ◽  
Bayan M Alsheheri ◽  
Khalid M Alotaibi ◽  
Mansour D Alharthi ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Ethylene Glycol ◽  
Silica Nanoparticles ◽  
Methyl Ether ◽  
Diblock Copolymer ◽  
Mesoporous Silica Nanoparticles ◽  
Poly Ethylene Glycol ◽  
Ethyl Methacrylate ◽  
Poly Ethylene ◽  
Glycol Methyl Ether

This paper introduces the synthesis of well-defined 2-(tert-butylamino)ethyl methacrylate-b-poly(ethylene glycol) methyl ether methacrylate diblock copolymer, which has been grafted onto mesoporous silica nanoparticles (PTBAEMA-b-PEGMEMA-MSNs) via atom transfer radical polymerization (ATRP). The ATRP initiators were first attached to the MSN surfaces, followed by the ATRP of 2-(tert-butylamino)ethyl methacrylate (PTBAEMA). CuBr2/bipy and ascorbic acid were employed as the catalyst and reducing agent, respectively, to grow a second polymer, poly(ethylene glycol) methyl ether methacrylate (PEGMEMA). The surface structures of these fabricated nanomaterials were then analyzed using Fourier Transform Infrared (FTIR) spectroscopy. The results of Thermogravimetric Analysis (TGA) show that ATRP could provide a high surface grafting density for polymers. Dynamic Light Scattering (DLS) was conducted to investigate the pH-responsive behavior of the diblock copolymer chains on the nanoparticle surface. In addition, multifunctional pH-sensitive PTBAEMA-b-PEGMEMA-MSNs were loaded with doxycycline (Doxy) to study their capacities and long-circulation time.

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