What You Need to Know
The process relies on the rapid ionic cross‑linking of sodium alginate by calcium ions, forming a Ca‑alginate hydrogel that encapsulates the liquid. Temperature, calcium concentration, and immersion time must be tightly controlled to achieve a membrane of the desired thickness and integrity. The technique is sensitive to trace calcium in the alginate solution and to osmotic pressure differences during transfer.
The Science
Primary Reaction
Cross‑linking of sodium alginate by Ca²⁺ ions to form a Ca‑alginate hydrogel membrane