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3 Vision

Figure 3.8: Photosensor that uses light (fluorescence) to measure pH (adapted from [13]).

the polymer, which in turn is dependent on how much the perfect alignment of the

π-orbitals in the chains is disturbed by bending or stressing the polymer chains through

outside forces. In this case, the binding of bacterial products by the lipid monolayer can

be detected as a simple color change from blue to red. This technology could be used

to develop sensors in the packaging of food that identifies, for example, spoiled meat.

In this case, the sensing element and the transducer is the polyacetylene layer, and the

signal is a simple visible color change.