For the investigation of surface topography, a Zeiss SIGMA VP-FESEM (Thornwood, NY, USA) field emission scanning electron microscope was employed. Samples were carefully placed onto aluminum stubs using carbon tape to ensure secure attachment. Subsequently, a thin layer of iridium, approximately 5 nm in thickness, was sputter-coated onto the sample surfaces using a Leica EM ACE600 sputter-coater (Leica, Wetzlar, Germany). The microscope was operated standard EDT at an accelerating voltage of 5 keV. The working distance (WD) was set at 15 mm. The resulting images allowed for the analysis and characterization of the surface features, including morphology, texture, and microstructural details of the freeze-dried crosslinked hydrogel samples.