Conformation and mechanical properties of diblock fibers*

We analyze the conformations of closed diblock fibers comprised of different bending rigidities and spontaneous curvatures. In each fiber, one block is a bare polymer while the other is an adsorbed protein-filament complex. The length fraction of each component and the total fiber length is controlled by tunable chemical potentials. We analytically calculate the shape of these two-component polymers for all values of the material parameters and chemical potentials. Our results yield: a complete analytical description of all possible two-component polymer conformations in two and three dimensions, a phase portrait detailing the parameter spaces in which these shapes occur, and the identification of spontaneous transitions between shapes driven by environmental changes.