Structural Study of a n-Alkylthiophene Polymer Grown in an Oriented Ultrathin Matrix of Alkylcellulose

A thin conducting film of an organic composite material made of n -butylcellulose and polythiophene has been fabricated. Thin oriented films of n -butylcinnamoylcellulose were deposited on a conducting substrate by the Langmuir−Blodgett technique and stabilized by cross-linking through UV irradiation. Subsequent exposure to a solution of 3-pentylthiophene followed by electropolymerization led to the formation of polypentylthiophene (PPT) within the alkylcellulose matrix. The structure of the composite material has been characterized by various spectroscopies, microscopies, and microanalysis techniques. The composite material is made of domains of PPT oriented along the cellulose backbones. In the case of large domains (up to 35 × 150 μm 2 ) there is a segregation between cellulose and PPT. However, for small domains (a few square microns), the two polymers seem to be intimately mixed and PPT is oriented at the molecular level. In all cases, the alkylcellulose stabilizes the PPT film in organic solvents and does not worsen the PPT conducting properties.