Patterning Semiconductor Nanocrystals in Polymer Films

Paquet, Chantal; Kumacheva, Eugenia

doi:10.1002/adfm.200700409

Cited by 31 publications

(24 citation statements)

References 43 publications

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“…Therefore, special measures are required to preserve the structure [ 2 ] after removing the fi eld, such as embedding within a polymer. Polymer composites and thin fi lms containing NPs, including magnetic NPs, are well known, [3][4][5][6][7][8][9][10][11][12][13][14][15][16] as are microgels [ 17 ] and microcapsules. [ 18 ] There is signifi cant interest in embedding NP chains within polymers for their potentially anisotropic mechanical, [ 19 ] electrical, optical, magnetic, and thermal properties.…”

mentioning

confidence: 99%

Magnetic Field‐Directed Self‐Assembly of Magnetic Nanoparticle Chains in Bulk Polymers

Krommenhoek

Tracy

2013

Part & Part Syst Charact

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Self-assembly is the thermodynamically guided organization of disordered systems into more highly ordered structures. The process of life exemplifi es the power and diversity of selfassembly, and understanding and controlling self-assembly is crucial for engineering advanced materials from molecular and nanoscale precursors. Nature has preceded researchers' efforts in magnetic fi eld-directed self-assembly (MFDSA) in magnetotactic bacteria, which navigate in the earth's magnetic fi eld using magnetically coupled chains of iron oxide nanoparticles (NPs). [ 1 ] Here, we report the MFDSA of magnetic NPs into threedimensional (3D) arrays of chains embedded within bulk poly mers, where no volatile solvent is present during the polymerization process. Application of uniform magnetic fi elds drives formation of magnetic NP chains that repel each other, resulting in their assembly into an array with quasiperiodic ordering. Removing the solvent from a 3D structure would cause collapse due to capillary forces. Therefore, special measures are required to preserve the structure [ 2 ] after removing the fi eld, such as embedding within a polymer. Polymer composites and thin fi lms containing NPs, including magnetic NPs, are well known, [3][4][5][6][7][8][9][10][11][12][13][14][15][16] as are microgels [ 17 ] and microcapsules. [ 18 ] There is signifi cant interest in embedding NP chains within polymers for their potentially anisotropic mechanical, [ 19 ] electrical, optical, magnetic, and thermal properties. Diverse applications are envisioned, including actuators, [ 20,21 ] artifi cial cilia, [ 22,23 ] ferrogels, [24][25][26] sensors, [ 27 ] polymer solar cells, [ 28,29 ] electromagnetic interference (EMI) shielding, [ 30,31 ] and drug delivery. [ 32 ] Several methods have been employed to form NP chains, often utilizing polymer templates to direct the assembly of NPs. [ 33 ] For example, there have been many studies of NP selfassembly at interfaces within [34][35][36][37][38][39][40][41][42][43][44][45][46] and on the surfaces of block copolymers, [47][48][49][50] but these systems are limited by the morphologies of block copolymers. Here, our focus is on template-free self-assembly of magnetic NPs, where MFDSA has potential to provide control and tunability over the self-assembly process without the use of templates.Stellacci and co-workers [ 51 ] have assembled magnetic NP chains in zero fi eld by crosslinking the ligand shells, [ 52 ] but most examples of magnetic NP chaining have utilized magnetic interactions between the NPs: Magnetotactic bacteria synthesize iron oxide NPs that form chains through magnetic interactions. Cryogenic TEM measurements of solutions of iron oxide NPs by Philipse and co-workers [ 53,54 ] showed that magnetic NPs spontaneously form disordered chains in solution in zero applied fi eld, if the NP diameter exceeds a minimum size. Pyun and co-workers [ 55,56 ] have also shown that strongly interacting Co NPs spontaneously form chains, and application of magnetic fi elds causes the chains to straig...

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mentioning

confidence: 99%

Magnetic Field‐Directed Self‐Assembly of Magnetic Nanoparticle Chains in Bulk Polymers

Krommenhoek

Tracy

2013

Part & Part Syst Charact

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“…To understand the role of polymerization in the enrichment of the surface of pores with the NRs, we examined the relative rates of polymerization‐driven phase separation and increase in viscosity of the system. The time before the beginning of PIPS was determined by measuring the cloud point of the monomer mixture as a function of polymerization time 17. The extinction was measured at 640 nm, in order to minimize the contribution from light absorption by the photoinitiator at 400 nm and by gold NRs at 518 and 787 nm.…”

Section: Resultsmentioning

confidence: 99%

A Study of Polymerization‐Induced Phase Separation as a Route to Produce Porous Polymer–Metal Materials

Dubinsky

Petukhova

Gourevich

et al. 2010

Macromol. Rapid Commun.

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We report the results of the experimental study of the preparation of hybrid porous polymer material carrying gold nanorods (NRs) on the surface of pores. The material was prepared by utilizing two effects occurring concurrently: the photoinitiated polymerization-induced phase separation in the polymer-solvent mixture and the migration of the NRs to the interface between the polymer and the porogen solvent. We show that the enrichment of the interface with the NRs is enhanced at high polymerization rate leading to the rapid phase separation. By contrast, more rapid increase in viscosity achieved at high polymerization rate does not have a significant effect on the segregation of NRs to the surface of pores.

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“…Photoluminescent NPs or nanorods may be patterned in polymer films by combining lithographic techniques with PIPS [12,13]. Production of pre-designed bidimensional patterns of photoluminescent regions is an important requirement for various photonic, biomedical and optoelectronic applications.…”

Section: Patterning Of Nps In Polymer Filmsmentioning

confidence: 99%

“…10 Fig .9 is a confocal fluorescence microscopy image showing a regular photoluminescent pattern generated from a 2 wt% solution of CdSe-ZnS core-shell NPs stabilized with trioctyl phosphine oxide in 2-ethylhexyl methacrylate, in the presence of hydroxycyclohexyl phenyl ketone as photoinitiator [12]. In order to generate regular patterns it was necessary to match the cloud point (start of PIPS) with the increasing viscosity of the polymerizing system, to use a film thickness less than 200 μ m to suppress natural convection patterns, and to select a convenient feature size of the mask [12]. When NPs were replaced by nanorods, the lateral diffusion produced an alignment of nanorods in the regions located under the mask [13].…”

Section: Patterning Of Nps In Polymer Filmsmentioning

confidence: 99%

Self-assembly of nanoparticles employing polymerization-induced phase separation

Williams

Hoppe

Zucchi

et al. 2014

Journal of Colloid and Interface Science

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Patterning Semiconductor Nanocrystals in Polymer Films

Cited by 31 publications

References 43 publications

Magnetic Field‐Directed Self‐Assembly of Magnetic Nanoparticle Chains in Bulk Polymers

Magnetic Field‐Directed Self‐Assembly of Magnetic Nanoparticle Chains in Bulk Polymers

A Study of Polymerization‐Induced Phase Separation as a Route to Produce Porous Polymer–Metal Materials

Self-assembly of nanoparticles employing polymerization-induced phase separation

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