Polymer hydrogels and/or microgels can be studied by several microscopic techniques. Light-microscopy (LM) visualizes samples in their natural state - submerged in water, but suffers from lower resolution.
Cryo-TEM microscopy exhibits the best resolution, but the method is not suitable for particle with sizes >300 nm. Cryo-SEM offers sufficient resolution and, at the same time, it allows observing even large particles.