All reagents were purchased from Sigma-Aldrich unless otherwise noted. THF was purchased as anhydrous and inhibitor free (>99.9). Poly(hexamethylene diisocyanate) -viscosity 1,300-2,200-was kept under nitrogen after opening the bottle. Methods Nuclear Magnetic Resonance (NMR) was done using a Varian 500 MHz spectrometer at ambient temperature. Attenuated total reflection (ATR) FT-IR spectra were recorded using a Perkin-Elmer Spectrum 100 in the region of 4000-650 cm -1 . Four scans were completed with a resolution of 2 cm -1 . A background measurement was performed prior to loading the sample onto the ATR for measurement. Raman spectroscopy (Renishaw in Via Reflex Raman Microscope and Spectrometer). Nd-YAG laser with a power of 0.5 mW at 532 nm was used for the data acquisition and the spectral range was kept from 300 cm -1 to 3000 cm -1 . Thermogravimetric analysis (TGA) was performed (Shimadzu, DTG-60H) from room temperature to 500°C with a heating rate of 10°C min -1 in a nitrogen atmosphere. Mechanical behaviour of the synthesized gel and hydrogel, a tensile test was performed. The test was performed using the Instron 5982 universal tensile system (Instron) with a 200 N static load cell and at tension rate of 5.0 %/ min up to failure of the samples under constant temperature and humidity conditions. Material tensile modulus (E) was determined from the linear portion of the stress-strain curve slope. Moreover, ultimate stress and fracture strain is also reported.Ion chromatography analysis were purchased as a service from water analysis laboratories of Istanbul Munipilacity Water and Sewege Administration (ISKI). Synthesis of semicarbazide gel: In a typical synthesis, 8.6 mL poly(hexamethylene diisocyanate) was added to an oven dried 100-mL round bottom flask together with 50 mL anhydrous tetrahydrofuran (THF) under inert conditions. This mixture was stirred for 10 minutes while keeping flask in an ice bath. 2.10gram ethyl carbazate was dissolved in 20 mL THF and added to the round bottom flask over 3-5 minutes in portions. Then, reaction was kept stirring for 60 more minutes. After, 100 µL water added and the solution was poured into glass petri dishes. Then, a watch glass was put over it for 2 days to let THF evaporate slowly. After, the watch glass was removed and all THF was evaporated for 2 more days. Finally, gel was peeled from the petri dish (ESI Figure ).