What is block copolymer lithography?
Block copolymer lithography is an emerging self-assembly technique for the large-area patterning of surfaces with regular nanosized features. We investigate the microphase separation behavior of Poly(styrene-b-methylmethacrylate) (PS-b-PMMA) block copolymers to create nanopores in a PS matrix in thin films.
How are block copolymers made?
Block copolymers are normally prepared by controlled polymerization of one monomer, followed by chain extension with a different monomer(1) to form AB or ABC block copolymers.
Which method is the best to make a block copolymer?
Living anionic polymerization
Living anionic polymerization provides the best and the most elegant method for preparing block copolymers by the sequential addition of different monomers because it can produce block copolymers in which each block has a predictable molecular weight in a wide range and a very narrow molecular weight distribution under …
What is block copolymer self assembly?
Block copolymers consist of two or more chemically distinct polymers that are covalently bound. These materials self-assemble into fascinating mesostructures with features on the nanometer length scale and have been the subject of intense research interest for about four decades.
What are block copolymers used for?
Block copolymers (but not exclusively) are interesting because they can “microphase separate” to form periodic nanostructures, as in the styrene-butadiene-styrene block copolymer shown at right. The polymer is known as Kraton and is used for shoe soles and adhesives.
What are copolymers used for?
Copolymerization is used to modify the properties of manufactured plastics to meet specific needs, for example to reduce crystallinity, modify glass transition temperature, control wetting properties or to improve solubility. It is a way of improving mechanical properties, in a technique known as rubber toughening.
Why do block copolymers self assemble?
Self-assembly of block copolymers can be used to design and control the shape and dimension of resulting nanostructures. The versatility and scalability of this method makes them highly attractive for the synthesis of advanced materials.
When were block copolymers discovered?
The most commonly studied TPEs are poly(styrene-b-isoprene-b-styrene) (SIS) and poly(styrene-b-butadiene-b-styrene) (SBS). These two types of BCPs were firstly developed by Holden and Milkovich through living anionic polymerization in the early 1960s [86].
What are block and graft copolymers?
The key difference between block and graft copolymer is that a block copolymer has blocks of repeating units whereas a graft copolymer has branches of repeating units. And, these repeating units represent the monomers that are used in the polymerization process to make this polymer.
What are copolymers in chemistry?
copolymer, any of a diverse class of substances of high molecular weight prepared by chemical combination, usually into long chains, of molecules of two or more simple compounds (the monomers forming the polymer).
Are there inorganic segments in block copolymer lithography?
The incorporation of inorganic segments into block copolymers is an attractive prospect, as it addresses both of these issues.
How are block copolymers used in the semiconductor industry?
Block copolymer lithography, a process where block copolymer self-assembly is integrated with conventional lithographic patterning, is emerging as a promising technology for addressing the future needs of the semiconductor industry. The ability of block copolymers to self-assemble into ordered nanodomains allows for simple,
What makes a block copolymer a macromolecular material?
Block copolymers (BCPs) are macromolecular materials comprised of two or more chemically different polymeric segments. As a result of their segmented structures BCPs have a propensity to phase-separate and order themselves into a range of complex morphologies on the nanoscale.