scholarly journals Microphase separation through competitive hydrogen bonding in self-assembled A-b-B/C diblock copolymer/homopolymer complexes

2009 ◽  
Vol 131 (21) ◽  
pp. 214905 ◽  
Author(s):  
Nishar Hameed ◽  
Nisa V. Salim ◽  
Qipeng Guo
Keyword(s):  
Hydrogen Bonding ◽  
Diblock Copolymer ◽  
Microphase Separation ◽  
Self Assembled

scholarly journals Hierarchical Self-Assembled Structures from Diblock Copolymer Mixtures by Competitive Hydrogen Bonding Strength

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2242 ◽  
Author(s):  
Tzu-Chun Tseng ◽  
Shiao-Wei Kuo
Keyword(s):  
Hydrogen Bonding ◽  
Ethylene Oxide ◽  
Diblock Copolymer ◽  
Structure Transition ◽  
Reversible Addition ◽  
Poly Ethylene Oxide ◽  
Self Assembled ◽  
Poly Ethylene ◽  
Chain Transfer Polymerization ◽  
Hydrogen Bonding Strength

In this work we prepared poly(styrene–b–vinylphenol) (PS-b-PVPh) by sequential anionic living polymerization and poly(ethylene oxide-b-4-vinylpyridine) (PEO-b-P4VP) by reversible addition fragmentation chain transfer polymerization (RAFT) by using poly(ethylene oxide) 4-cyano-4-(phenylcarbonothioylthio)pentanoate (PEO-SC(S)Ph) as a macroinitiator with two hydrogen bonded acceptor groups. When blending with disordered PEO-b-P4VP diblock copolymer, we found the order-order self-assembled structure transition from lamellar structure for pure PS-b-PVPh to cylindrical, worm-like, and finally to PEO crystalline lamellar structures. Taking the advantage of the ΔK effect from competitive hydrogen bonding strengths between PVPh/P4VP and PVPh/PEO domains, it could form the hierarchical self-assembled morphologies such as core–shell cylindrical nanostructure.

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.

Block Copolymer Self-assembly on Ethylene Glycol (EG) Self-assembled Monolayer (SAM) for Nanofabrication

2012 ◽  
Vol 1450 ◽  
Author(s):  
Dipu Borah ◽  
Sozaraj Rasappa ◽  
Barbara Kosmala ◽  
Justin D. Holmes ◽  
Michael A. Morris
Keyword(s):  
Ethylene Glycol ◽  
Diblock Copolymer ◽  
Microphase Separation ◽  
Random Copolymer ◽  
Fine Tuning ◽  
Self Assembled Monolayer ◽  
Perpendicular Orientation ◽  
Interfacial Energies ◽  
Self Assembled ◽  
Nanoscale Features

ABSTRACTNanostructure templates fabrication from P(S-b-MMA) thin films requires precise control of interfacial energies to achieve perpendicular orientation of microdomains to the substrate surface and can be obtained by modifying the oxide layer on silicon with a covalently anchored hydroxyl-terminated random copolymer P(S-r-MMA) termed a “neutral brush”. This commonly employed method enables precise fine-tuning of interfacial energies, but involves a lengthy process, requires starting materials that are commercially available but expensive, and results in a relatively thick under layer that can interfere with subsequent surface processing. We report here the microphase separation behaviour of an asymmetric P(S-b-MMA) diblock copolymer on electronic substrates modified with ethylene glycol (EG) self-assembled monolayer (SAM) as alternative to standard random copolymer brush. The diblock copolymer films deposited on EG SAMs upon thermal annealing spontaneously generates features with sub-lithographic resolution and pitch with perpendicular orientation. Selective etching provides a rapid route for the generation of PS template structures as the PMMA domains are etched at a faster rate. These templates can subsequently be used as etch masks to generate nanoscale features. We use state of the art lithography to generate sub-μm features and within these generate nm sized copolymer templates. Graphoepitaxy method proved a successful approach for the alignment of the microphase separated structures. This method of EG SAM driven self-0assembly provides a simple, rapid, yet tuneable approach for surface neutralization and nanofabrication technique for creating high density nanoscale features for the nanoelectronic industry.

scholarly journals Quadruple Hydrogen Bond-Containing A-AB-A Triblock Copolymers: Probing the Influence of Hydrogen Bonding in the Central Block

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4705
Author(s):  
Boer Liu ◽  
Xi Chen ◽  
Glenn A. Spiering ◽  
Robert B. Moore ◽  
Timothy E. Long
Keyword(s):  
Hydrogen Bonding ◽  
Self Assembly ◽  
Microphase Separation ◽  
Triblock Copolymers ◽  
Random Copolymer ◽  
Thermomechanical Properties ◽  
Structure Property ◽  
Scanning Calorimetry ◽  
Central Block ◽  
Quadruple Hydrogen Bonding

This work reveals the influence of pendant hydrogen bonding strength and distribution on self-assembly and the resulting thermomechanical properties of A-AB-A triblock copolymers. Reversible addition-fragmentation chain transfer polymerization afforded a library of A-AB-A acrylic triblock copolymers, wherein the A unit contained cytosine acrylate (CyA) or post-functionalized ureido cytosine acrylate (UCyA) and the B unit consisted of n-butyl acrylate (nBA). Differential scanning calorimetry revealed two glass transition temperatures, suggesting microphase-separation in the A-AB-A triblock copolymers. Thermomechanical and morphological analysis revealed the effects of hydrogen bonding distribution and strength on the self-assembly and microphase-separated morphology. Dynamic mechanical analysis showed multiple tan delta (δ) transitions that correlated to chain relaxation and hydrogen bonding dissociation, further confirming the microphase-separated structure. In addition, UCyA triblock copolymers possessed an extended modulus plateau versus temperature compared to the CyA analogs due to the stronger association of quadruple hydrogen bonding. CyA triblock copolymers exhibited a cylindrical microphase-separated morphology according to small-angle X-ray scattering. In contrast, UCyA triblock copolymers lacked long-range ordering due to hydrogen bonding induced phase mixing. The incorporation of UCyA into the soft central block resulted in improved tensile strength, extensibility, and toughness compared to the AB random copolymer and A-B-A triblock copolymer comparisons. This study provides insight into the structure-property relationships of A-AB-A supramolecular triblock copolymers that result from tunable association strengths.

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