text: An interesting phenomenon called self-lubricate spinning can facilitate the demolding of the fiber and enables the continuous production of hydrogel fiber from tubular mold. During the polymerization process, if an inert second polymer is present, it will be particularly expelled from the formed network and being able to move with relative ease. The linear polymer on the surface of the crosslinked network also contains water solvent due to the osmic pressure, thus, a lubrication layer is formed. Therefore, the solidified polymer fiber can exit the tube with decreased friction force and continuous production can be achieved.
  An example would be the production the PAAM/PAMPS semi-interpenetration network hydrogel fiber reported by Zhao et al. The pregel solution was the mixture of PAMPS, AAM, PEGDA (crosslinker), and 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone (photoinitiator). The pregel solution was fed into a PTFE tube at a constant speed, with UV light being used to initiate the reaction.