Effect of volume fraction φ of hard sphere crowders upon equilibrium constant for association of two spherical monomers with R1 = 1 to form a spherocylindrical dimer with twice the volume, and (a) L2 = 0, R2 = 1.26 (spherical dimer); (b) L2 = 2/3, R2 = 1; (c) L2 = 1, R2 = 0.928; (d) L2 = 1.5, R2 = 0.851; and (e) L2 = 2, R2 = 0.794.