Simple Syntheses and Basic Properties

The historical aspects of doped P(Ac), have been dealt with at some length in Chapter 1. Much before Shirakawa et al. s discovery of doped P(Ac) [4], Natta and coworkers employed Ziegler-Natta (Z-N) polymerization using Al(Alk)/org-anotitanium to obtain non-conducting P(Ac) [537], The commonest method for production of P(Ac), which is subsequently doped, remains Z-N polymerization. 

A typical, simple, Z-N synthesis of P(Ac) may be described [405] The walls of a glass reaction vessel are simply wetted with a solution of Al(Et)3 4- Ti(OBut)4 (4 1 M/M) in toluene. Acetylene monomer in gaseous form is introduced at pressures from 0.01 to 1 atm. A well-adhering film of P(Ac) grows on the walls in times ranging from a minute to an hour, dependent upon temperature, pressure, and other reaction conditions. The film so obtained, of thickness in the 0.1 /itm to several cm, is washed and dried, and then peeled off from the vessel walls. 

When the reaction is carried out at room temperature, a mixture of 60%-cis and 40%-trans is typically obtained at -78 C, the product is nearly entirely cis-isomer at 150 C, using decane solvent base, the product is nearly entirely trans-isomer. The morphology of the product is entangled fibrils of diameter from ca. 5 to 100 nm (typically 20 nm) and no particular orientation (fibrils as large as 1 pm have been 

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