\sf - Used to turn on sans serif mode for uppercase and lowercase letters and digits, and for uppercase Greek.
{ \sf}
\sf command turns on sans serif mode for uppercase and lowercase letters and digits, and for uppercase Greek.
\sf ABCDEFGHIJKLMNOPQRSTUVWXYZ
\sf 0123456789
\sf abcdefghijklmnopqrstuvwxyz
ABCDE 01234 abcde
{\sf AB\Delta\Gamma\Lambda}\ AB\Delta\Gamma\Lambda
\sf AB \rm AB
\sf{AB}CD