Temperature Dependence of the Morphology of Thin Diblock Copolymer Films as Revealed by Neutron Reflectivity

1989 ◽  
Vol 166 ◽  
Author(s):  
T. P. Russell ◽  
S. H. Anastasiadis ◽  
S. K. Satija ◽  
C. F. Majkrzak
Keyword(s):  
Thin Films ◽  
Temperature Dependence ◽  
Density Profile ◽  
Diblock Copolymer ◽  
Diblock Copolymers ◽  
Decay Length ◽  
Neutron Reflectivity ◽  
Copolymer Films ◽  
Lamellar Morphology ◽  
Oriented Parallel

ABSTRACTThe order-disorder transition in thin films of symmetric diblock copolymers of polystyrene and polymethylmethacrylate has been investigated by neutron reflectivity. At temperatures above the order-disorder temperature, TMST, a surface induced oscillatory segment density profile with an exponential decay length, χ, is observed. The inverse of decay length 1/≤ TMST a lamellar morphology oriented parallel to the surface propagates through the entire specimen.

Investigation of Diblock Copolymer thin film Morphology for Nanolithography

1996 ◽  
Vol 461 ◽  
Author(s):  
Miri Park ◽  
Christopher Harrison ◽  
Paul M. Chaikin ◽  
Richard A. Register ◽  
Douglas Adamson ◽  
...  
Keyword(s):  
Thin Films ◽  
Silicon Nitride ◽  
Diblock Copolymer ◽  
Diblock Copolymers ◽  
Microphase Separation ◽  
Large Area ◽  
Etching Technique ◽  
Copolymer Films ◽  
Self Assembled ◽  
Self Assembled Layer

ABSTRACTThe microphase separated morphology of diblock copolymers can be used to generate well-ordered nanometer scale patterns over a large area. To achieve this goal, it is important to understand and control the behavior of diblock copolymer thin films on substrates, which can differ from the bulk behavior. We have investigated the morphologies and ordering in thin polystyrene-polybutadiene (PS-PB) diblock copolymer films on bare silicon and silicon nitride substrates, and also on polymethylmethacrylate (PMMA) coated substrates. The PS-PB copolymers are synthesized to form, in bulk, PB cylinders or spheres in a PS matrix. In thin films (10–60 nm thick), prepared by spin-coating, we observe that the morphology and ordering of the microdomains are affected by strong wetting constraints and a reduced chain mobility on the substrate. The thinnest self-assembled layer of the copolymer films shows no in-plane microphase separation on both types of substrates. The PS blocks wet the PMMA substrates whereas the PB blocks wet the bare substrates as well as the air interface. Hence, different film thicknesses are necessary on the two types of substrates to obtain a uniform film of the first self-assembled cylindrical or spherical microdomain layer. The first layer of the cylindrical copolymer can vary from cylindrical to spherical morphology with a few nanometer decrease in film thickness. In the case of spherical PS-PB diblock copolymer films, we observe that the ordering of the microdomains is improved in the films on the PMMA substrates, compared to those on the bare substrates. We also demonstrate a successful transfer of the microdomain patterns to silicon nitride substrates by a reactive ion etching technique.

Array of Fe3O4 Nanoparticles in PS-b-P2VP thin Films

2013 ◽  
Vol 345 ◽  
pp. 193-196
Author(s):  
Xin Kang Gao ◽  
Jun Liu ◽  
Ting Hua Wang ◽  
Xue Li ◽  
Xiao Kai Zhang
Keyword(s):  
Thin Films ◽  
High Temperature ◽  
Composite Film ◽  
Self Assembly ◽  
Spin Coating ◽  
Diblock Copolymers ◽  
Carbon Substrate ◽  
Mixed Solution ◽  
Long Time ◽  
Oriented Parallel

In this study, a method to generate arrays of Fe3O4 nanoparticles (MNPs) via block copolymer (BC) self-assembly was developed. A composite film of polystyrene-block-poly (2-vinylpyridine) (PS-b-P2VP)/MNPs was first prepared by spin-coating the PS-b-P2VP/MNPs mixed solution on a carbon substrate. After the composite film was annealed at high temperature for 2 days, it was found that the modified MNPs could be selectively incorporated into P2VP cylinders in PS-b-P2VP diblock copolymers and the P2VP cylinders were oriented parallel to the substrate. For a long time annealing (10 days), the P2VP cylinders become normal to the substrate and MNPs are located at the interface of P2VP and PS phases.

Neutron reflectivity studies of the surface-induced ordering of diblock copolymer films

1989 ◽  
Vol 62 (16) ◽  
pp. 1852-1855 ◽  
Author(s):  
S. H. Anastasiadis ◽  
T. P. Russell ◽  
S. K. Satija ◽  
C. F. Majkrzak
Keyword(s):  
Diblock Copolymer ◽  
Neutron Reflectivity ◽  
Copolymer Films

Electric Field Induced Control of Thin Film Diblock Copolymer Domain Orientation

1996 ◽  
Vol 461 ◽  
Author(s):  
T. L. Morkved ◽  
W. A. Lopes ◽  
M. Lu ◽  
A. M. Urbas ◽  
H. M. Jaeger ◽  
...  
Keyword(s):  
Thin Films ◽  
Electric Field ◽  
Electric Fields ◽  
Diblock Copolymer ◽  
Diblock Copolymers ◽  
Quantitative Measure ◽  
Domain Orientation ◽  
External Electric Fields ◽  
Silicon Nitride Membrane ◽  
Field Lines

ABSTRACTLocal control of domain orientation in diblock copolymer thin films is demonstrated through the use of external electric fields. Thin films of a polystyrene-polymethylmethacrylate diblock copolymers, denoted P(S-b-MMA), were spin coated onto silicon nitride membrane substrates with prefabricated in-plane electrodes, forming cylindrical PMMA microdomains. Films annealed under an applied electric field (E ≤ 37V/μm) at 250°C for 24h under an argon atmosphere showed an alignment of the cylindrical microdomains parallel to the electric field lines. A quantitative measure of the degree of alignment was obtained by correlating the local field strength, E, and direction with the observed cylinder orientation. The alignment was found to saturate above E≈30V/μm, and to decrease rapidly as E falls below this value.

Applications of Neutron Reflectivity Measurements to Nanoscience: Thin Films and Interfaces

MRS Bulletin ◽  
2003 ◽  
Vol 28 (12) ◽  
pp. 918-922 ◽  
Author(s):  
John F. Ankner ◽  
Hartmut Zabel
Keyword(s):  
Thin Films ◽  
Density Profile ◽  
Materials Science ◽  
Kinetic Studies ◽  
Film Plane ◽  
Small Sample ◽  
Neutron Reflectivity ◽  
Nuclear Density ◽  
Essential Difference ◽  
Reflectivity Data

AbstractNeutron reflectivity has matured in recent years from an exotic method used only by a few experts to an essential tool for the investigation of thin films and interfaces on the nanoscale. In contrast to x-ray reflectivity, which provides electron density profiles, neutron reflectivity reveals the nuclear density profile. This is an essential difference when exploring hydrogenous materials such as polymers, Langmuir–Blodgett films, and membranes. Furthermore, neutrons carry a magnetic moment that interacts with the magnetic induction of the film, revealing, in addition to the nuclear density profile, the magnetic density profile in layers and superlattices. Recent developments in the analysis of off-specular neutron reflectivity data enable the characterization of chemical and magnetic correlations within the film plane on nanometer to micron length scales. A new generation of pulsed neutron sources, featuring flux enhancements of factors of 10–100 over existing sources, will make these types of measurements even more exciting, while kinetic studies, pump-probe, and small-sample experiments will become feasible, opening new windows onto nanoscale materials science.

scholarly journals Interpreting Neutron Reflectivity Profiles of Diblock Copolymer Nanocomposite Thin Films Using Hybrid Particle-Field Simulations

2018 ◽  
Vol 51 (8) ◽  
pp. 3116-3125 ◽  
Author(s):  
Jyoti P. Mahalik ◽  
Jason W. Dugger ◽  
Scott W. Sides ◽  
Bobby G. Sumpter ◽  
Valeria Lauter ◽  
...  
Keyword(s):  
Thin Films ◽  
Diblock Copolymer ◽  
Neutron Reflectivity ◽  
Particle Field ◽  
Hybrid Particle ◽  
Nanocomposite Thin Films

Block Copolymer Thin Films Above and Below the Order-Disorder Transition Temperature

2000 ◽  
Vol 629 ◽  
Author(s):  
Ratchana Limary ◽  
Peter F. Green
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Molecular Weight ◽  
Transition Temperature ◽  
Block Copolymer ◽  
Film Thickness ◽  
Diblock Copolymer ◽  
Diblock Copolymers ◽  
Microphase Separation ◽  
Disorder Transition Temperature

ABSTRACTSymmetric diblock copolymers undergo a disorder to order transition below a microphase separation transition temperature. In this temperature range the structure is characterized by alternating lamellae of thickness L. In thin film geometries, the lamellae are oriented normal to the substrate if there is a preferential interaction between either of the block constituents and the substrate/copolymer or copolymer/vacuum interfaces. Depending on the relation between the film thickness and L, the topography of the film might comprise of holes, islands or spinodal-like structures. We show that in a polystyrene-b-poly(methyl methacrylate) diblock copolymer of molecular weight 20, 000 g/mol, above the microphase separation transition temperature, the topography of the film depends on the thickness. A heirarchy of bicontinuous patterns and holes is observed with increasing film thickness for films thinner than 35 nm.

scholarly journals Segregation of Maghemite Nanoparticles within Symmetric Diblock Copolymer and Triblock Terpolymer Patterns under Solvent Vapor Annealing

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1286
Author(s):  
George Zapsas ◽  
Dimitrios Moschovas ◽  
Konstantinos Ntetsikas ◽  
Andreas Karydis-Messinis ◽  
Nikolaos Chalmpes ◽  
...  
Keyword(s):  
Thin Films ◽  
Diblock Copolymer ◽  
Self Assembly ◽  
Diblock Copolymers ◽  
Maghemite Nanoparticles ◽  
Solvent Vapor ◽  
Vapor Annealing ◽  
The Matrix ◽  
Solvent Vapor Annealing ◽  
Selective Placement

Block copolymers (BCPs), through their self-assembly, provide an excellent guiding platform for precise controlled localization of maghemite nanoparticles (MNPs). Diblock copolymers (di/BCP) represent the most applied matrix to host filler components due to their morphological simplicity. A series of nanocomposites based on diblock copolymer or triblock terpolymer matrices and magnetic nanoparticles were prepared to study and compare the influence of an additional block into the BCP matrix. MNPs were grafted with low molecular weight polystyrene (PS) chains in order to be segregated in a specific phase of the matrix to induce selective localization. After the mixing of the BCPs with 10% w/v PS-g-MNPs, nanocomposite thin films were formed by spin coating. Solvent vapor annealing (SVA) enabled the PS-g-MNPs selective placement within the PS domains of the BCPs, as revealed by atomic force microscopy (AFM). The recorded images have proven that high amounts of functionalized MNPs can be controllably localized within the same block (PS), despite the architecture of the BCPs (AB vs. ABC). The adopted lamellar structure of the “neat” BCP thin films was maintained for MNPs loading approximately up to 10% w/v, while, for higher content, the BCP adopted lamellar morphology is partially disrupted, or even disappears for both AB and ABC architectures.

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