How can i get the ends of my hair to stay straight? i want it PIN straight?

i straighten my hair every day. when i finish with it, its perfectly straight, and stays straight for the most part. By the ime i get to school, the ends have curled in kind of. It's not the straightener, cause i have CHI.

I try to use the protectant spary, but its hard when i dont have a lot of time, and it makes my hair not stay straight. using a lot of product makes my hair gross, so i dont really.

what do i do? i cant ask my haircutter, cause they alkways yell at me for straightening my hair too often. bottom line is, im not going to stop. and i wont get a straight perm cause the hairdressers all wont do it for me because my hair is fine. I have medium-length hair, its about 3 or 4 inches past my shoulder. i really want my hair to be straight all over and all day! what do i do? i have naturally really curly hair, but dont suggest leaving it that way cause it has no shape %26amp; i hate it. HELP.How can i get the ends of my hair to stay straight? i want it PIN straight?
Blow dry you hair and use Paul Mitchell's Super Skinny Serum.. with what your doing now your going to be bald in about 10-20 yearsHow can i get the ends of my hair to stay straight? i want it PIN straight?
i straighten my hair everyday too, and i think your problem may be humidity, there is this hairspary from herbal essences for straighting hair (dangerously straight, pink bottle), and if you use it just at the ends with a hot straightner it may solve your problem.