Check alginate properties (from supplier). Not all alginates will create the spherical beads in contact with gelling solution. Also, if your alginate is to viscous, try to decrease its concentration (very viscous alginates solutions usually create elongated or even fiber-like structure). Decrease the concentration of oil phase as well as reduce the stirring rate during beads formation. If you use oils as active ingredients, please consider to prepare stable emulsions (in alginate solution) prior to encapsulation. Inadequate mixing can limits encapsulation efficiency.

I had tried decreasing Na Alginate sol from 3% to 0.5% but the results were more poor (more easy formation of elongated fiber like structure.).

I did the emulsification and mixed with Na Alginate sol and dispersed it in methanol. The dispersion was very fine but hardening through CaCl2 didn't go well (Fiber formation).

If you got drops of hardened alginate once you wet them, you may recover them directly before a web is formed (using a kind of shrimp net).

I don't understand the role of methanol is this process? Is you disperse your alginate solution into methanol, alginate will dehydrate and most probably precipitate. Probably this water removal disturb structural property of alginate that can't form stable gel with calcium.

Well, structural issue is occurring even without using methanol (dripping Na Alginate directly in hardening bath). I pre-emulsified methanol and then added Na Alginate in it. it gives stable result. Still worried about controlling size.

In my case, when I remove the dropped CNTs with Na alginate from CaCl2, we obtained very small balls and we don t understand the pb. Why this dimension change when thé balls are dried. Thanks for you

Hi,

The reduction of the size of the beads upon drying is due to the water removal and to the van der Waals forces which were generated during the drying step. Such vdW forces tend to increase the interaction between the CNTs during the water removal from the beads, and the direct consequence is the reduction of the final beads size at the dried state. I hope the explanation can help.

Cuong

yes cuong it's clear I am making some different concentration of CaCl2 to avoid this beads diameter reduction and to have some macroscopic shape for environment. what you can say about this.

Thanks for your help