A drip chamber for an infusion tube, including: a first end including a drip tube； a second end including an exit port； and a wall connecting the first and second ends and including an interior surface with a hydrophobic portion. The drip chamber includes a space enclosed by the interior wall and the first and second ends. The hydrophobic portion of the interior surface repels liquid contacting the hydrophobic coating. The hydrophobic portion of the interior surface enables light to refract through the hydrophobic portion and the wall in the same manner as is the case when the hydrophobic portion is not present on the interior surface.
