Since right- and left-handed EMACs are mirror images of each other, these two conformatoins should have exactly the same energy. In other words, an infinitely long EMAC has a doubly degenerate ground states. At the absolute temperature T=0, an EMAC can stay either in the left- or right-handed conformation. But at T>0, one may have conformational fluctuations to other excited structures above the ground state. If the barrier to turn left-handed conformation to right-handed conformation is small, soliton excitation may become energetically favorable. An infinitely long EMAC with soliton (or domain wall) consists of three parts: a semi-infinitely long left- and right-handed structures on two sides of polymer and a soliton (a domain wall) with finite lengths in between. It is not easy to determine the size and creation energy of a soliton in an EMAC polymer, though.
Base on my experience with beaded EMACs, it is quite easy to make a soliton in the beaded model as shown in the following picture. So it is reasonable to assume that soliton excitation should be easy in the real, infinitely long EMAC polymers.