Extracting chemical energy by growing disorder: efficiency at maximum power

We consider the efficiency of chemical energy extraction from the
environment by the growth of a copolymer made of two constituent units in the
entropy-driven regime. We show that the thermodynamic nonlinearity associated
with the information processing aspect is responsible for a branching of the system
properties such as power, speed of growth, entropy production, and efficiency,
with varying affinity. The standard linear thermodynamics argument which
predicts an efficiency of 1/2 at maximum power is inappropriate because the
regime of maximum power is located either outside of the linear regime or on a
separate bifurcated branch, and because the usual thermodynamic force is not
the natural variable for this optimization.