Encapsulation of ZnS:Mn<sup>2+</sup> nanocrystals with diblock copolymers

Kim, Sang-Cheol; Diana, Frédéric S.; Petroff, P. M.; Krämer, Edward J.; Ootsu, Takeshi; Murase, Tomohide

doi:10.1002/polb.20934

Cited by 2 publications

(2 citation statements)

References 33 publications

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“…Figure 2a shows a single particle (in cross section) embedded in the PS-rich matrix of the BCP. P2VP is known to strongly wet many oxide, 9 metal, 25 and semiconductor 26 surfaces. This is presumably the case with the hematite particles, as well, leading to the formation of a PS-P2VP brush layer that compatibilizes the particles within the PS matrix of the BCP.…”

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Mutual Alignment of Block Copolymer−Magnetic Nanoparticle Composites in a Magnetic Field

et al. 2010

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For the past ∼30 years, polymer nanocomposites (PNCs) 1 and block copolymers (BCPs) 2 have represented two extremely active areas of research within the polymer science community. It was inevitable, then, that the two topics should overlap; block copolymer/nanoparticle composites represent a relatively new and exciting field in materials research. A large portion of such work has, to date, sought to employ the well-ordered microphaseseparated structures available in block copolymers as scaffolds to direct the spatial arrangement of the nanofiller. 3,4 Indeed, effective control over the spatial location and/or orientation of the nanofiller particles in PNCs offers great possibilities for dramatically improved composite properties. 1 In the block copolymer field, great strides have been made in developing techniques to globally orient the BCP microdomains using external fields 5 (e.g., shear 6 or electric fields 7 ) or surfaces, [8][9][10][11] even further enhancing the possibility for the creation of nanocomposites with precisely defined morphology.In this Communication, we present a general method for creation of aligned block copolymer/nanoparticle (BCP/NP) composites, although via something of an inverse approach: an external (magnetic) field is used to define the spatial orientation of rodshaped magnetic NPs, which then serve as structure-directing agents for neighboring BCP domains. Specifically, the oriented NPs, which are incorporated at a concentration of only a few percent, present templating surfaces for the alignment of cylindrical block copolymer nanodomains. In a sense, our approach is an extrapolation of the graphoepitaxy technique, which can be used to template BCP cylinder orientation in thin films, 10,11 to thicker films, and eventually into the bulk. The ability of rod-shaped NPs to nucleate coaxially oriented BCP cylinders has recently been established. 12,13 There has also been a fair amount of work using magnetic fields to orient block copolymers, although it is necessary to use copolymers which contain moieties or semicrystalline domains with appreciable magnetic susceptibility. 5,[14][15][16][17] In the absence of such a condition, we introduced the rod-shaped nanoparticles, which are capable of being magnetically aligned. Using this kind of scheme to induce reorientation in lyotropic liquid crystal/nanomagnet composites has also been demonstrated. 18,19 The composite under study consisted of a polystyrene-blockpoly(2-vinylpyridine) (PS-P2VP) diblock copolymer, which forms cylindrical microdomains of P2VP in a PS matrix, 20 and spindletype hematite (R-Fe 2 O 3 ) particles, which were synthesized by the forced hydrolysis of Fe(ClO 4 ) 3 , according to procedures previously described by Ocaña et al. 21 The particles, an example of which is shown in the transmission electron microscopy (TEM) image in Figure 1a, had an average diameter of 55 ( 6 nm and an average long axis length of 330 ( 38 nm (see the Supporting Information, Figure S1). Such hematite particles are weakly ferromagnetic and hav...

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Mutual Alignment of Block Copolymer−Magnetic Nanoparticle Composites in a Magnetic Field

et al. 2010

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“…[26] Similar findings were already reported by some studies. [16,31] The elongation at break of PC/ABS/MWCNT composites decreases with the increase in CNT content because of the natural resistance of CNTs to straining, which is ascribed to their high Young's modulus. Thus, the matrix becomes highly restrained mechanically.…”

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Investigation of polycarbonate/acrylonitrile butadiene styrene/multiwall carbon nanotube nanocomposites under impact loading

Taheri

Esfahani

Nakhlband

et al. 2016

Polymers for Advanced Techs

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In this study, the effect of polycarbonate (PC)/acrylonitrile butadiene styrene (ABS)‐reinforced multiwall carbon nanotube (MWCNT) nanocomposites under a high‐velocity impact was investigated. PC/ABS (70/30 w/w)/MWCNT nanocomposites containing 1, 2, and 4 wt% were used to manufacture samples for this study. The samples were fabricated in sheet form with 100 × 100 mm dimensions and tested by gas gun for high‐velocity impact tests. The experimental results indicate that the energy absorption, limit velocity, and tensile modulus of the nanocomposite samples increased by approximately 121%, 52%, and 103% for the PC/ABS (70/30 w/w)/2 wt% MWCNT samples respectively. These results were confirmed by a transmission electron microscopy analysis test that was conducted for the state of dispersion of MWCNTs in the nanocomposite samples. The transmission electron microscopy results show that the best morphological structure of carbon nanotube at the interface of PC and ABS is that for the nanocomposite containing 2 wt% MWCNTs, which led to improved interface of the nanocomposites and higher mechanical properties. Copyright © 2016 John Wiley & Sons, Ltd.

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Encapsulation of ZnS:Mn²⁺ nanocrystals with diblock copolymers

Cited by 2 publications

References 33 publications

Mutual Alignment of Block Copolymer−Magnetic Nanoparticle Composites in a Magnetic Field

Mutual Alignment of Block Copolymer−Magnetic Nanoparticle Composites in a Magnetic Field

Investigation of polycarbonate/acrylonitrile butadiene styrene/multiwall carbon nanotube nanocomposites under impact loading

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Encapsulation of ZnS:Mn2+ nanocrystals with diblock copolymers

Cited by 2 publications

References 33 publications

Mutual Alignment of Block Copolymer−Magnetic Nanoparticle Composites in a Magnetic Field

Mutual Alignment of Block Copolymer−Magnetic Nanoparticle Composites in a Magnetic Field

Investigation of polycarbonate/acrylonitrile butadiene styrene/multiwall carbon nanotube nanocomposites under impact loading

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Encapsulation of ZnS:Mn²⁺ nanocrystals with diblock copolymers