Dear Mithra,
If I understand your question correctly, you have pre-polymerized linear poly-NIPAM at hand and want to make a gel from it. Or do you mean making a gel from not-yet-polymerized monomeric NIPAM?
If you mean the latter, then this is easy: prepare a solution of the NIPAM monomer (for example, at 100 g/L concentration), along with crosslinker (N,N'-methyleneisacrylamide is a frequently used one; typically people use 1-10 g/L if the main monomer is used at 100 g/L) in water and add a little amount of radical initiator, for example, ammoniumpersulfate (APS) or a suitable photoinitiator, and then start the reaction by either shining UV light on your vessel or by adding a reaction accelerator, for example, N,N,N'.N-tetramethylethylenediamine (TEMED). I recommend using about 0.5 g/L of APS, along with 2.5 g/L of TEMED. Depending on how much APS/TEMED you use and depending on at which temperature the reaction is conducted, you will receive either homogeneous (clear, transparent) or heterogeneous (turbid) gels. Here's a typical paper for reference:
"Influence of Formation Conditions on Spatial Inhomogeneities in Poly(N-isopropylacrylamide) Hydrogels." J. Nie, B. Du, W. Oppermann, Macromolecules 2004, 37, 6558.
If your question was pointing to my first guess, I have made good experience with making photocrosslinkable copolymers of pNIPAAm and then photogelling those in aqueous solution by UV irradiation. Here's a paper on this:
"Tracer Diffusion in Heterogeneous Polymer Networks." F. Di Lorenzo, S. Seiffert, Macromol. Chem. Phys. 2014, 215, 2097
Greetings,
Sebastian Seiffert
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Materials Science
- Materials Chemistry
- Polymer Chemistry