In her relationship with Ismene, does Antigone reveal qualities that are not admirable?

Antigone is not the best of sisters.  I think that comes
out fairly quickly.  Once Antigone becomes fixated on honoring her brother, who is
Ismene's brother as well, everything else becomes secondary, including the bond between
she and her sister.  Ismene might not possess the head- strong will as Antigone, but she
is not a bad sister.  She pleads to Creon to pardon Antigone, and even pleads with
Antigone not to pursue this.  She even wishes to share the punishment with Antigone. 
She does all of this to save her sister's life.  Yet, Antigone treats Ismene with scorn
or, at best, indifference.  Ismene represents the traditional notion of women who feel
that they were second class citizens.  However, Antigone, ironically, repeats the same
silencing of voices that Greek society does when she refuses to acknowledge the acts of
Ismene.  Interestingly enough, the feminist discards the voice of the traditional woman,
repeating the cycle of negation that the feminist swears against in the first place.  It
might be a stroke of genius on the part of Sophocles to display a trend that becomes
apparent in many freedom fighters.  The pursuit of the "cause" and the reason for their
fight is one that precludes emotional attachments from forming.  This might be the
reason why the individuals who were so driven to fight for a social or political cause
ended up possessing fractured relationships in the realm of the personal.  Antigone's
relationship with her sister reflects this dichotomy.