[R] Changing ggplot2 legend key/title to custom text

[BARLAS Marios 247554]

Hi all, 

ok I have this issue: 

I want to change my graphs legends to custom text, often requiring the use of superscripts/subscripts
I tried to use this instruction I found on stack overflow: 

labs(x = "R(Ohm)", y= "CDF", aesthetic= " Content (%)" )

but it wont' seem to work. 

Also tried bquote for super/ subscripts 

xlab(bquote(~x~/(~x~ + ~MO[2]~)* '(%)'))

but I get an error that the / operator is not recognized. 

Any ideas on how I can solve these issues ? 

Thanks in advance,
Marios Barlas