I'm synthesizing the cellulose hydrogels by the freeze-thaw gelation. I want to know if the orientation and sizes of ice crystal or the sizes and distribution of pores will affect the properties of cellulose hydrogels such as mechanical properties, light transmittance, or swelling ratio and so on.
Thanks.
Dear Ray Yang, thé negative effect of FT increases with abuse of its repetition. Drastic loss of mechanical properties and morphology of pores and their dimensions take place. Please refer to the following documents. My Regards
https://www.researchgate.net/publication/257102740_The_effect_of_freeze-thaw_cycles_on_microstructure_and_physicochemical_properties_of_four_starch_gels
DOI:10.1007/s13197-016-2350-5
https://doi.org/10.1021/acsmacrolett.9b00140
https://doi.org/10.1111/1541-4337.12050
Hi Ray, my pH.D group had done similar work. So I got some experience which could be helpful. But I am not sure how is the microstructure of your formed hydrogel. If the pore are orientated after gelation, the mechanical property of the hydrogel should dramatically increased on the direction of the pore orientation direction. The transparency of hydrogel should decreased, because of the destructive of uniform microstructure of the material. And the transmittance should be different in the direction of the orifice and in its perpendicular direction. If the pore are not well orientated, the exist of big sized pore in hydrogel network will still decrease the transparence of hydrogel, and leading to weak mechanical property. If you want to increase the mechanical property of hydrogel, incorporating inorganic nanoparticles, increase the monomer or cross-linker amount should help, or by introducing double network into the hydrogel structure should work. The swelling ratio should not be influence too much by the pore size formed by ice, it is decided by the functional groups on hydrogel network as well as the strength of it. Hope it helps.
Sure, what does the hydrogel look when you prepare in your way? I guess, it should be less transparent than normal polymerized hydrogel. If you lower the temperatures of solution, the solubility of the cellulose will decrease, that could be the reason for the precipitation.
The conventional gel has wider pore size distribution and is weaker and more fragile.
Plz check out the link below
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4756301/
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