I am using chitosan polymer for naoparticles and I adopted ionic gelation method, but during particle size analysis it shows two peaks: one at 380nm and another at 4800nm but it does not shows signs of agglomeration in peak. Please see attached file.
How was the MW distribution of your chitosan before? Does it monomodal? Just to find out the agglomeration issue, you can sonicate your particles and do the analysis again.
First of all, how does the solution look like? Does it look turbid or nicely dispersed? If you get such a high reading and you cannot see any signs of aggregation you most likely have just dust in your sample.
According to your figure, the major peak shows a size distribution between 100 to 2000 nm, which is quite broad. You may wish to reduce the chitosan concentration in your aqueous solution and try again.
Hi thanks for adding tht size distribution data. Usually the high level of care should be taken in preparing samples for size distribution analysis. From the data I understand that the the solution employed for measurement has polydispersed particles ( very broad peak at 500 nm; Polydispersed Index = PDI value > 0.1 means polydispersed particles in solution. This could also have been reflected in the cumulative curve with steps). If you really wanted to look on whether the aggregation occurs or not, it would be a good idea to do the time scale experiment to follow the peaks stability. And also repeat the measurement with care avoiding the errors in sample preparation (mostly caused by dust particles - from any source).
Note: For the size distribution data, always take care of these points: half height width line broadening of a peak; PDI value < 0.1 - lesser the value decribes the size distribution close to homogeneous distribution; Cumulative curve. Time scale experiment woudl suggest the stabiltiy of the nanoparticles.
Hi Reddy. Having read your DLS report, I recommend you to use SEM to check if your particles are agglomerate. I have done a bit of DLS measurement, to my experience, DLS often give ambiguous results when the particles have little agglomeration. Even, when you see a peak with good PDI, you may found the particles are all agglomerate in SEM graphs. So I recommand you to use SEM (or TEM if your sample is core-shell structure) to further characterize.
Good luck!
- Badges
- Science topic
- Similar topics
- Chemistry
- Nanotechnology
- Nanostructured Materials
- Nanoparticles