There is a layer of PE coating on the inside of the single-sided coated paper cup, which can prevent the water in the cup from penetrating the paper cup and causing water to leak out.
The inner and outer sides of the double-sided coated paper cups have PE coating, which is mainly used for cold drinks, which can prevent the condensed water on the outer wall of the cup from penetrating the paper cup and causing the cup to become soft.
How to choose depends on your needs. If you only hold room temperature water or hot water, it is recommended to use a single-sided coated paper cup.