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Host-guest self-assembly in block copolymer blends.

Park WI, Kim Y, Jeong JW, Kim K, Yoo JK, Hur YH, Kim JM, Thomas EL, Alexander-Katz A, Jung YS - Sci Rep (2013)

Bottom Line: Our self-consistent field theory (SCFT) simulation results theoretically support that the precise registration of a spherical BCP microdomain (guest, B-b-C) at the center of a perforated lamellar BCP nanostructure (host, A-b-B) can energetically stabilize the blended morphology.As an exemplary application of the hybrid nanotemplate, a nanoring-type Ge2Sb2Te5 (GST) phase-change memory device with an extremely low switching current is demonstrated.These results suggest the possibility of a new pathway to construct more diverse and complex nanostructures using controlled blending of various BCPs.

View Article: PubMed Central - PubMed

Affiliation: Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.

ABSTRACT
Ultrafine, uniform nanostructures with excellent functionalities can be formed by self-assembly of block copolymer (BCP) thin films. However, extension of their geometric variability is not straightforward due to their limited thin film morphologies. Here, we report that unusual and spontaneous positioning between host and guest BCP microdomains, even in the absence of H-bond linkages, can create hybridized morphologies that cannot be formed from a neat BCP. Our self-consistent field theory (SCFT) simulation results theoretically support that the precise registration of a spherical BCP microdomain (guest, B-b-C) at the center of a perforated lamellar BCP nanostructure (host, A-b-B) can energetically stabilize the blended morphology. As an exemplary application of the hybrid nanotemplate, a nanoring-type Ge2Sb2Te5 (GST) phase-change memory device with an extremely low switching current is demonstrated. These results suggest the possibility of a new pathway to construct more diverse and complex nanostructures using controlled blending of various BCPs.

No MeSH data available.


Related in: MedlinePlus

Host-guest self-assembly of blended BCPs.The chemical structures of the PDMS-b-PS and PS-b-PFS diblock copolymers (di-BCPs) used for the self-assembly is shown. The schematics of the as-spun and self-assembled morphologies of the blended BCPs are also presented. A mixed solvent vapor of heptane and toluene induces the formation of a perforated lamellar morphology of PDMS-b-PS that can precisely accommodate the spherical morphology of PS-b-PFS because heptane is selectively segregated in the PDMS blocks, whereas toluene swells PS and PFS blocks more preferentially. An inorganic dots-in-holes nanostructure is produced by oxidation of the hierarchically assembled BCP microdomains. Plasma oxidation selectively removes the PS, while oxidizing PDMS and PFS into stable inorganic materials. The array of metallic nanorings can be obtained from pattern-reversal of the dots-in-holes nanostructure.
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f1: Host-guest self-assembly of blended BCPs.The chemical structures of the PDMS-b-PS and PS-b-PFS diblock copolymers (di-BCPs) used for the self-assembly is shown. The schematics of the as-spun and self-assembled morphologies of the blended BCPs are also presented. A mixed solvent vapor of heptane and toluene induces the formation of a perforated lamellar morphology of PDMS-b-PS that can precisely accommodate the spherical morphology of PS-b-PFS because heptane is selectively segregated in the PDMS blocks, whereas toluene swells PS and PFS blocks more preferentially. An inorganic dots-in-holes nanostructure is produced by oxidation of the hierarchically assembled BCP microdomains. Plasma oxidation selectively removes the PS, while oxidizing PDMS and PFS into stable inorganic materials. The array of metallic nanorings can be obtained from pattern-reversal of the dots-in-holes nanostructure.

Mentions: Figure 1 schematically conceptualizes an example of such hybrid nanostructures: hexagonally perforated lamellae (HPL) of one di-BCP (A-b-B) combined with the spherical microdomains of another di-BCP (B-b-C). The compositional choice was designed for the fabrication of nanoscale ring geometries, and the complex nanostructures can be realized by selectively removing the B polymer and reversing the remaining features comprised of the A and C blocks. It should be noted that such complex nanostructures cannot be prepared from a single di-BCP123233. In order to fabricate the designed nanostructures, we chose poly(dimethylsiloxane-b-styrene) (PDMS-b-PS) and poly(styrene-b-ferrocenyldimethylsilane) (PS-b-PFS) di-BCPs, where the pure organic PS (block B) are readily selectively removed and the inorganic-containing PDMS (block A) and PFS (block C) can be oxidized to form robust inorganic nanostructures that can subsequently serve as a high-resolution etch mask as well as a removable template for the formation of functional nanostructures.


Host-guest self-assembly in block copolymer blends.

Park WI, Kim Y, Jeong JW, Kim K, Yoo JK, Hur YH, Kim JM, Thomas EL, Alexander-Katz A, Jung YS - Sci Rep (2013)

Host-guest self-assembly of blended BCPs.The chemical structures of the PDMS-b-PS and PS-b-PFS diblock copolymers (di-BCPs) used for the self-assembly is shown. The schematics of the as-spun and self-assembled morphologies of the blended BCPs are also presented. A mixed solvent vapor of heptane and toluene induces the formation of a perforated lamellar morphology of PDMS-b-PS that can precisely accommodate the spherical morphology of PS-b-PFS because heptane is selectively segregated in the PDMS blocks, whereas toluene swells PS and PFS blocks more preferentially. An inorganic dots-in-holes nanostructure is produced by oxidation of the hierarchically assembled BCP microdomains. Plasma oxidation selectively removes the PS, while oxidizing PDMS and PFS into stable inorganic materials. The array of metallic nanorings can be obtained from pattern-reversal of the dots-in-holes nanostructure.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3824169&req=5

f1: Host-guest self-assembly of blended BCPs.The chemical structures of the PDMS-b-PS and PS-b-PFS diblock copolymers (di-BCPs) used for the self-assembly is shown. The schematics of the as-spun and self-assembled morphologies of the blended BCPs are also presented. A mixed solvent vapor of heptane and toluene induces the formation of a perforated lamellar morphology of PDMS-b-PS that can precisely accommodate the spherical morphology of PS-b-PFS because heptane is selectively segregated in the PDMS blocks, whereas toluene swells PS and PFS blocks more preferentially. An inorganic dots-in-holes nanostructure is produced by oxidation of the hierarchically assembled BCP microdomains. Plasma oxidation selectively removes the PS, while oxidizing PDMS and PFS into stable inorganic materials. The array of metallic nanorings can be obtained from pattern-reversal of the dots-in-holes nanostructure.
Mentions: Figure 1 schematically conceptualizes an example of such hybrid nanostructures: hexagonally perforated lamellae (HPL) of one di-BCP (A-b-B) combined with the spherical microdomains of another di-BCP (B-b-C). The compositional choice was designed for the fabrication of nanoscale ring geometries, and the complex nanostructures can be realized by selectively removing the B polymer and reversing the remaining features comprised of the A and C blocks. It should be noted that such complex nanostructures cannot be prepared from a single di-BCP123233. In order to fabricate the designed nanostructures, we chose poly(dimethylsiloxane-b-styrene) (PDMS-b-PS) and poly(styrene-b-ferrocenyldimethylsilane) (PS-b-PFS) di-BCPs, where the pure organic PS (block B) are readily selectively removed and the inorganic-containing PDMS (block A) and PFS (block C) can be oxidized to form robust inorganic nanostructures that can subsequently serve as a high-resolution etch mask as well as a removable template for the formation of functional nanostructures.

Bottom Line: Our self-consistent field theory (SCFT) simulation results theoretically support that the precise registration of a spherical BCP microdomain (guest, B-b-C) at the center of a perforated lamellar BCP nanostructure (host, A-b-B) can energetically stabilize the blended morphology.As an exemplary application of the hybrid nanotemplate, a nanoring-type Ge2Sb2Te5 (GST) phase-change memory device with an extremely low switching current is demonstrated.These results suggest the possibility of a new pathway to construct more diverse and complex nanostructures using controlled blending of various BCPs.

View Article: PubMed Central - PubMed

Affiliation: Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Republic of Korea.

ABSTRACT
Ultrafine, uniform nanostructures with excellent functionalities can be formed by self-assembly of block copolymer (BCP) thin films. However, extension of their geometric variability is not straightforward due to their limited thin film morphologies. Here, we report that unusual and spontaneous positioning between host and guest BCP microdomains, even in the absence of H-bond linkages, can create hybridized morphologies that cannot be formed from a neat BCP. Our self-consistent field theory (SCFT) simulation results theoretically support that the precise registration of a spherical BCP microdomain (guest, B-b-C) at the center of a perforated lamellar BCP nanostructure (host, A-b-B) can energetically stabilize the blended morphology. As an exemplary application of the hybrid nanotemplate, a nanoring-type Ge2Sb2Te5 (GST) phase-change memory device with an extremely low switching current is demonstrated. These results suggest the possibility of a new pathway to construct more diverse and complex nanostructures using controlled blending of various BCPs.

No MeSH data available.


Related in: MedlinePlus