  We theoretically study the self-propulsion of a laser-heated Janus particle
in a near critical waterlutidine mixture, and relate its velocity vp and
squirmer parameter \b{eta} to the wetting properties of its two hemispheres.
For non-ionic surface forces, the particle moves the active cap ahead, except
at strong driving, where a more complex behavior occurs if one of the
hemispheres attracts water and the other lutidine. Both vp and \b{eta} show
non-monotonic dependencies on the heating power, and may even change sign.
Including the drift of the counterions due to the composition gradient, we find
that a charged cap with lutidine affinity drives the particle the cap ahead,
and with water affinity in the opposite direction, in agreement with
experimental findings.
