Functionalised-polyaniline

The antimicrobial properties of conductive functionalised-polyaniline (f-PANI) have been investigated by exploring their interaction with different bacteria. It was observed that low concentrations of PANI strongly inhibited the growth of wild-type Escherichia coli. Pseudomonas aeruginosa and Staphylococcus aureus as well as several antibiotic-resistant clinical pathogens [18]. 

A few reports are available wherein conducting polymers have been incorporated in materials such as graphite [179] and carbon paste [180]. However, these have not yet been commercialised. A glucose biosensor utilising covalently coupled GOD to poly(o-amino benzoic acid) (PAB, a carboxy group functionalised polyaniline) has been described [42]. 

An alternative and often facile route to appropriately functionalised ICPs, that avoids the synthetic problems outlined in (ii) above, is the use of sulfonated species containing the desired molecular recognition/receptor site as the dopant anion for the conducting polymer chains. For example, calixarene-containing polypyrroles [34] and polyanilines [35] for selective metal ion detection have recently been prepared via the use of sulfonated calixarenes as dopant anions. We have similarly found that the incorporation of metal complexing agents such as sulfonated 8-hydroxyquinoline as dopants in polypyrroles provides a simple route to metal ion-selective ICPs [36]. 

Conducting organic polymers such as polyacetylenes, polyanilines and polypyrroles are of interest in electronic devices. One of the difficulties associated with their application is that they are degraded upon exposure to the atmosphere. For this reason, attempts have been made to prepare them encapsulated within zeolites, for example by polymerising acetylene over metal-exchanged zeolites. A recent report shows that polyacetylenes can also be prepared inside functionalised MOFs (see Section 10.3.3). It remains a challenge to prepare materials of acceptable properties for applications. 

We have approached the goal of functionalised monolayer fabrication by synthesis of a group of azobenzene-containing amphipathic molecules. Such molecules can be deposited by either chemisorption or physisorption and should allow hybrid films to be fabricated. The monolayers are reversibly photochromic (which might prove useful in sensor fabrication) and are capable of chemical activation for surface attachment of macromolecules, etc. In addition, the activated surface can be photochemi-cally modified so that photolithography could be used to fabricate surface structures such as danains of particular ccxnposition. With particular regard to conductive polyers, polyanilines could be locally formed as discussed later. 

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