Refere Unicode Charactor it will make subscripts and superscripts
Here is an example,
for,
x² - U+00Bx2 -> X\u00B2
x³ - U+00Bx3 -> X\u00B3
x⁶ - U+207x6 -> X\u2076
, etc.....
[button setTitle:@"X\u00B2" forState:UIControlStateNormal];
[button setTitle:@"X\u00B3" forState:UIControlStateNormal];
[button setTitle:@"X\u2076" forState:UIControlStateNormal];
like that...