Polymerization A process in which many

Another important reaction involving certain unsaturated hydrocarbons is polymerization, a process in which many small molecules are joined together to form a large molecule. Polymerization will be discussed in Section 22.5. 

A "stereoselective" polymerization is a process in which macromolecules containing only one type of configurational unit are formed by incorporation of one stereoisomer from a mixture into a growing polymer chain. There are as many different types of macro-molecules as different stereoisomers present in the initial monomer mixture. 

The rotaxane assembly is adopted by many enzymes that operate on nucleic acids and proteins. In the case of processive enzymes, the catalytic reaction drives the sequential motion of the enzyme on its polymeric substrate. Therefore, these enzymes can be viewed as molecular motors powered by chemical reactions and moving one-dimensionally on a track, in which fuel is provided by the track itself. An initial attempt to carry out processive catalysis with a synthetic rotaxane has been described [69]. 

Solution polymerization. Solution polymerization involves polymerization of a monomer in a solvent in which both the monomer (reactant) and polymer (product) are soluble. Monomers are polymerized in a solution that can be homogeneous or heterogeneous. Many free radical polymerizations are conducted in solution. Ionic polymerizations are almost exclusively solution processes along with many Ziegler-Natta polymerizations. Important water-soluble polymers that can be prepared in aqueous solution include poly(acrylic acid), polyacrylamide, poly(vinyl alcohol), and poly(iV-vinylpyrrolidinone). Poly(methyl methacrylate), polystyrene, polybutadiene, poly(vinyl chloride), and poly(vinylidene fluoride) can be polymerized in organic solvents. 

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