Adsorption of polyampholytes to charged surfaces

The adsorption of flexible polyampholytes to charged surfaces has been inve stigated. The electrostatic interactions are included in a mean-field manne r, while the chain connectivity is treated by Metropolis Monte Carlo (MC) s imulations. For large enough surface charge densities, adsorption is found both for neutral polyampholytes and for polyampholytes carrying the same ne t charge as the surfaces. The simulation results are used to check the reli ability of previously proposed analytical theories. The exponents predicted in those scaling relations are not reproduced by MC simulations. The simul ations show that the size of the adsorbed polyampholyte initially grows wit h increasing surface charge density, but for sufficiently charged surfaces it reaches a maximum and starts to decrease. This general behavior is quali tatively captured by scaling arguments. The MC simulations do not bear any evidence for the existence of three disparate regimes where the polyampholy te adsorbs in different conformations.