tailieunhanh - Conductive Polymers and Plastics in Industrial Applications Part 6

Tham khảo tài liệu 'conductive polymers and plastics in industrial applications part 6', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 100 Conductive Polymers and Plastics 14 The major drawback of such systems is that organic solvents such as dichloromethane m-cresol and N-methylpyrrolidone must be used which are industrially undesirable. Two potential product areas can be explored for large scale electrochemical production of conducting polymers these being aqueous colloidal dispersions or water soluble polymers. A brief description of these polymer technologies is discussed below. CONDUCTING POLYMER COLLOID PROCESSING To overcome the water solubility limitations of conducting polymers aqueous dispersions that are sterically stabilized15-21 have been prepared. More recent approaches involve the use of a core shell approach where an inner inert colloidal core such as SiO2 or TiO2 is coated with the conducting polymer in the presence of a steric stabilizer in order to yield uniform colloid morphology and particle size All of these approaches involve the production of the conducting polymer component via a chemical oxidative 27 This technique involves oxidizing the monomer using a chemical agent and has limitations as discussed above. The electrochemical synthesis of conducting polymer colloids is based upon removing the polymer as it is formed above the electrode surface and stabilizing into colloidal particles with a polymeric surfactant . a steric stabilizer . In the early stages of electropolymerization the process of oxidation and oligomerization is said to occur within the diffusion layer above the electrode As polymerization continues the oligomer solubility in the electrolyte solution is exceeded and subsequently precipitates onto the electrode surface. If the electrolyte flows across the electrode surface fast enough it is possible for the polymer to be swept away from the electrode before deposition This process is further facilitated by the presence of the steric The final product is a colloidal .