A heteropolymer, also called a copolymer, is a polymer formed when two different types of monomer are linked in the same polymer chain. A polymer is a generic term used to describe a substantially long molecule. ... In chemistry, a monomer (from Greek mono one and meros part) is a small molecule that may become chemically bonded to other monomers to form a polymer. ...
A special type of copolymer is called a "block copolymer". Block copolymers are made up of blocks of different polymerized monomers. For example, PS-b-PMMA is short for polystyrene-b-poly(methyl methacrylate) and is made by first polymerizing styrene, and then subsequently polymerizing MMA. This polymer is a "diblock copolymer" because it contains two different chemical blocks. You can also make triblocks, tetrablocks, pentablocks, etc. Diblock copolymers are made using "living polymerization" techniques, such as atom transfer free radical polymerization (ATRP), reversible addition fragmentation chain transfer (RAFT), living cationic or living anionic polymerizations.
Block copolymers are interesting because they can "microphase separate" to form nanoscopic sized structures.
Think of oil and water. They don't mix together- they MACROphase separate. Block copolymers behave in a similar way called MICROphase separation. You have an "oil-like" first block and a "water-like" second block. They want to get as far from each other as possible, but they are covalently bonded! So they're not going to get very far. This causes "microphase separation" in which the "oil" and "water" phases separate to form nanometer-sized structures. These structures can look like sphere of PMMA in a matrix of PS or visa versa, or they could be stripes or cylinders. Structures on the nanoscale can be used for creating even smaller devices that could potentially be used in computer memory, nanoscale-templating and nanoscale separations.
In more official terms, polymer scientists wouldn't use "oil-like" and "water-like" to describe the polymer block's interactions. Polymer scientists use thermodynamics to describe how the different blocks interact. The "interaction parameter", also called "chi" gives an indication on how different chemically the two blocks are and if they will microphase separate. If chi is large, the blocks will microphase separate. If chi is too small, the different blocks "like" each other enough to mix.
Types of copolymers
Since a copolymer consists of at least two types of repeating units (not structural units), copolymers can be classified based on how these units are arranged in the polymer. These include In polymer chemistry, a structural unit is a building block of a polymer chain. ... In polymer chemistry, a structural unit is a building block of a polymer chain. ...
Edwards, M. Muller, M. Stoykovich, H. Solak, J. de Pablo, and P. Nealey, "Dimensions and shapes of blockcopolymer domains assembled on lithographically defined chemically patterned substrates," Macromolecules, 40(1), 90-96, 2007.
Stoykovich, E. Edwards, H. Solak, and P. Nealey, "Phase behavior of symmetric ternary block copolymer-homopolymer blends in thin films and on chemically patterned surfaces," Phys.
Kim, B. Kim, K. Kim, C. Koo, M. Stoykovich, P. Nealey, and H. Solak, "Defect structure in thin films of a lamellar blockcopolymer self-assembled on neutral homogeneous and chemically nanopatterned surfaces," Macromolecules, 39(16), 5466-5470, 2006.
The modified blockcopolymer composition of the present invention is a resinous composition excellent in impact resistance, adhesion, paint adhesion, weatherability, resistance to thermal deterioration, transparency and gloss or a rubbery or leather-like composition excellent in heat resistance, abrasion resistance, compression set resistance, adhesion, transparency, oil resistance, weatherability and resistance to heat aging.
The ionically crosslinked modified blockcopolymer which is used in the present invention is thermoplastic, and a composition obtained by mixing this modified blockcopolymer with the component (a) is processable at high temperatures, and the ionic crosslinkage is a reversible crosslinkage.
Unmodified blockcopolymers shown in Table 1 were prepared by subjecting butadiene and styrene to anionic block copolymerization in n-hexane or cyclohexane as a solvent by using n-butyl lithium as a polymerization catalyst and tetrahydrofuran as a vinyl content adjusting agent.
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