Hair that is dry and damaged can often be difficult to style. As hair becomes more damaged, it will be more resistant to thermal styling with a curling iron or flat iron. As a result, you will have to use even more heat in order to get the hair curled or straightened, which will only result in even more damaged hair. It can be a pretty frustrating cycle.
In order to get hair to curl, the hydrogen bonds inside of the cortex of the hair must be broken, and this is done with heat. The more water that is inside the hair, the more hydrogen bonds the hair will have. This is why dry and damaged hair is often difficult to curl- because there are fewer hydrogen bonds inside the hair. This is also why setting wet hair in rollers and sitting under a dryer will result in a longer-lasting curl than a curling iron set.
This process is similar to permanently curling the hair by using a perm solution. Perms use chemicals to break the disulfide bonds inside of the hair, while heat is used to break the weaker hydrogen bonds. This explains why perms last for months, while curling iron sets and roller sets are temporary.
Since it is necessary to have a certain amount of moisture inside the hair in order to curl it, those with dry and damaged hair should use a high-quality conditioner. While using a conditioner won’t make the hair any easier to curl at first, it will make the hair much more easy to curl after several weeks of regular conditioning.
One way to improve curling is to very lightly mist the hair with water before using a curling iron. Allow a minute or two for the moisture to penetrate into the hair, and never use a curling iron on hair that is too wet or else you may scorch your hair and give yourself a nasty steam burn in the process.
It also helps to spray the hair with a finishing spray while it is still wound around the barrel of the iron. When you remove the iron, allow the curl to cool completely before touching it. This cooling down process is important in setting the curl. By the way, this is exactly why there’s a button on your blowdryer that will send out a blast of cool air; this “cold shot” helps to set the style.
Now that you understand the process of curling hair, it will be much easier to get your hair to curl.