Phase transition of semiflexible lattice vesicles

Abstract

The existence of a crumpling transition of a three-dimensional vesicle model on the cubic lattice with fixed surface area N subject to bending rigidity κ ⩾ 0 is reported. Using a Monte Carlo method, the transition characteristics of bending energy U, specific heat C, volume V, radius of gyration R and the corresponding three eigenvalues λ k are discussed. The specific heat exhibits increasing and shifted maxima with increasing surface area N and decreasing bending constant κ, respectively, which seems to indicate a continuous transition. Well above the transition point κ c the conformations are comparable to compact spheres, which become on the average more oblate approaching κ c from above. At κ < κ c one observes branched-polymer-like structures. A two-step transition process for the conformational transformation at finite N is proposed, and the possible existence of a unique crumpling point at κ=κ c with different scaling behavior, as compared to the rigid and the branched phases, is discussed.