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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

Time evolution of the self-assembled morphology.(a) SEM images of samples treated for various annealing times. Due to the use of solvothermal treatment at 85°C, the morphological transition occurred rapidly. (b) Schematic representation of morphological development, showing that the PS pores containing multiple PFS dots are spontaneously split into one-to-one matched microdomain structures. (c) Average pore-area (blue) and PDMS area fraction (red) as a function of annealing time.
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f5: Time evolution of the self-assembled morphology.(a) SEM images of samples treated for various annealing times. Due to the use of solvothermal treatment at 85°C, the morphological transition occurred rapidly. (b) Schematic representation of morphological development, showing that the PS pores containing multiple PFS dots are spontaneously split into one-to-one matched microdomain structures. (c) Average pore-area (blue) and PDMS area fraction (red) as a function of annealing time.

Mentions: The transformation from the as-cast disordered morphology with separate PDMS and PFS microdomains to an ordered structure clearly occurred with solvent treatment time as shown in Figure 5. The decreased average area per pore and the increased PDMS area fraction during the initial 5 minutes (Figure 5c) suggest that rises with treatment time. At the very early stage of treatment (1 – 5 sec), the PDMS microdomains merged to form networked structures. With further increase of the treatment time, the number of PFS spheres per pore decreased due to the separation of larger pores into smaller ones (Figure 5a and Figure 5b). The average pore size and number of PFS spheres per pore reached plateaus within 5 minutes of treatment. The spontaneous subdivision of PS perforations and the invariability of the pore size irrespective of the VDS45/VSF35 ratio (Figure 4d) for the optimized Vhep/Vtol imply that the nanostructure is a thermodynamically stable morphology in the solvent annealed state. These results also exclude the possibility that the ordered structure is formed by the accidental trapping of SF35 BCP chains in the PS perforations of DS45.


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)

Time evolution of the self-assembled morphology.(a) SEM images of samples treated for various annealing times. Due to the use of solvothermal treatment at 85°C, the morphological transition occurred rapidly. (b) Schematic representation of morphological development, showing that the PS pores containing multiple PFS dots are spontaneously split into one-to-one matched microdomain structures. (c) Average pore-area (blue) and PDMS area fraction (red) as a function of annealing time.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f5: Time evolution of the self-assembled morphology.(a) SEM images of samples treated for various annealing times. Due to the use of solvothermal treatment at 85°C, the morphological transition occurred rapidly. (b) Schematic representation of morphological development, showing that the PS pores containing multiple PFS dots are spontaneously split into one-to-one matched microdomain structures. (c) Average pore-area (blue) and PDMS area fraction (red) as a function of annealing time.
Mentions: The transformation from the as-cast disordered morphology with separate PDMS and PFS microdomains to an ordered structure clearly occurred with solvent treatment time as shown in Figure 5. The decreased average area per pore and the increased PDMS area fraction during the initial 5 minutes (Figure 5c) suggest that rises with treatment time. At the very early stage of treatment (1 – 5 sec), the PDMS microdomains merged to form networked structures. With further increase of the treatment time, the number of PFS spheres per pore decreased due to the separation of larger pores into smaller ones (Figure 5a and Figure 5b). The average pore size and number of PFS spheres per pore reached plateaus within 5 minutes of treatment. The spontaneous subdivision of PS perforations and the invariability of the pore size irrespective of the VDS45/VSF35 ratio (Figure 4d) for the optimized Vhep/Vtol imply that the nanostructure is a thermodynamically stable morphology in the solvent annealed state. These results also exclude the possibility that the ordered structure is formed by the accidental trapping of SF35 BCP chains in the PS perforations of DS45.

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