Abstract
We perform an exact enumeration study of polymers formed from a (quenched) random sequence of charged monomers ±q0. Such polymers, known as polyampholytes, are compact when completely neutral and expanded when highly charged. Our exhaustive search includes all spatial conformations and quenched sequences for up to 12-step (13-site) walks. We investigate the behavior of the polymer as a function of its overall excess charge Q and temperature T. At low temperatures there is a phase transition from compact to extended configurations when the charge exceeds Qcq0/N. There are also indications of a transition for small Q between two compact states on varying temperature. Numerical estimates are provided for the condensation energy, surface tension, and the critical exponent ν.
| Original language | English |
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| Pages (from-to) | 835-846 |
| Number of pages | 12 |
| Journal | Physical Review E |
| Volume | 52 |
| Issue number | 1 |
| DOIs | |
| State | Published - 1995 |