  A device is investigated that continuously and directly converts light into
mechanical energy, using polymers and photodissociation. A polymer brush
tethered to a surface, is brought into contact with a parallel plate a small
distance above it that contains reaction sites where photodissociation of bound
polymer and light can occur. Under the appropriate conditions, the collective
effect of these polymers is to apply a force parallel to the plates, converting
incoming light into mechanical work. Numerical work is carried out to
understand this effect, a three dimensional Langevin simulation, solution to
the Fokker Planck equation, and a one dimensional Monte Carlo simulation.
Theoretical analysis of the Fokker Planck equation is used to study a model
where equilibration of the unbound state occurs and equilibration to a
metastable equilibrium is achieved in the bound state. It is shown that the
work per cycle can be made much larger than the thermal energy but at the
expense of requiring a greatly diminished photodissociation rate. Parameters
are discussed in order optimize mechanical energy conversion.
