What is block copolymer lithography?
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.
What is the difference between a block and a graft copolymer?
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.
How do you make block copolymer?
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.
How are block polymers formed?
What is Block co polymer?
A block copolymer is defined as a polymer comprising molecules in which there is a linear arrangement of blocks, a block being defined as a portion of a polymer molecule in which the monomeric units have at least one constitutional or configurational feature absent from the adjacent portions. 1, 2.
What are polyoxyalkylene siloxane copolymers?
Polyoxyalkylene siloxane copolymers and alkyl-polyoxyalkylene siloxane copolymers (copolymers) are formed by reacting allyloxy terminated alkoxylates (polyethers) with dimethicone.10-12The typical molecular weight range for the
What is polyalkylene glycol?
Polyalkylene glycol is the common name for the homopolymers of ethylene oxide, propylene oxide, or butylene oxide; or the copolymers of ethylene oxide, propylene oxide, and/or butylene oxide. Although polyalkylene glycol is the common usage, Chemical Abstractsrefers to these materials as polyoxyalkylene glycols.
What are the melting and boiling points of ethylene oxide block copolymers?
Under the generic CAS No. 68937-54-2 (dimethylsiloxane, ethylene oxide block copolymer), the following were reported: melting point -14°C, boiling point >250°C, and density 1.035 g/mL at 25°C.4
What is the siloxane to polyether ratio for copolymers?
The siloxane to polyether ratio also varies, depending on the hydrophilic-lipophilic balance needs for the copolymer applications as non-ionic surfactants. Typically the molecular weight of these copolymers is greater than 1000 g/mol. The reaction requires an excess amount of polyethers to ensure the formation of the resulting copolymer.13
