Science has revolutionized our daily life. So significant is the impact of science that we can hardly imagine our life without several home appliances and gadgets of daily use. Take for example the start of our day that begins with getting ready for a fresh start. What do we require for that? A pair of clothes—ironed and ready to be adorned. Today, we will demystify the science behind ironing clothes. Have you ever wondered why do we need ironing? How do we get those creases or wrinkles on our clothes? Let’s get back to the basics.
Clothes usually are made from plant-based fabrics that are composed of cellulose, a polymer. We know that polymers are large structures, i.e., macromolecules composed of many repeated subunits. In cellulose these repeating subunits are of glucose which are joined together to form a chain-like linear structure.
Glucose molecules have a sticky nature but that is what allows them to bind to the neighbouring cellulose molecules through hydrogen bonding, i.e., the electrostatic attraction between the hydrogen atom (H) of one molecule and an electronegative atom of another molecule. As glucose is composed of carbon, hydrogen and oxygen, and has hydroxyl groups (OH), so electrostatic force of attraction occurs between hydrogen (H) of one molecule and oxygen (O) of another molecule. Individually these bonds are weak but they become strong when combined, thus giving strength to the fabric.
Didn’t get any of that chemistry? Let’s make it even simpler. Hydrogen bonds have a dynamic nature due to which they are constantly in the process of breaking and reforming. They can break and reform in new dimensions, and that is how clothes get wrinkles or form the shape in which they are left, resulting in creases.
What happens when we wash our clothes? When they are dipped in water, the water molecules, which also have hydrogen and oxygen, come in contact with the cellulose molecules and break the hydrogen bond. Yet again, the disruption of hydrogen bonds is apparent in the wrinkled shape of fabric once dried. Now, how do we get our wrinkle-free-fabric back? A Harry Potter aficionado would scream ‘accio iron!’
But wait, isn’t it all about chemical nature of clothes and some high school hydrogen bonding? Where is the science behind ironing? We got you!
It is the combination of heat and moisture (steam in iron) that breaks the hydrogen bond. When we apply pressure, cellulose molecules are forced to get back to their original state, i.e., to be parallel to each other. So, do you see now? It takes some level of coercion and heated cruelty to get the molecules underlying clothes straightened.