The large size of the emulsion can be attributed to air bubbles, impurities, fluctuations in the density of water, surfactant micelles... Nanoparticles is considered to be the size of 100 nm. Then clearly manifested their size effects. 

Best regards.

You r right sir...these are some possibilites

Hi

There is a difference between the peak maximum and the z-average. I've found nice explanation here:

https://nanoscalereslett.springeropen.com/articles/10.1186/1556-276X-8-381

By the way, nano is defined as below 100nm, BUT it's normal that in DLS measurements you can obtain larger structures from some contamminations, air bubles or even dust).

So, if you measured few times and have almost the same results I will say that there is nanoemulsion.

In out of the main topic - is it stable for long time?

All the best

I would be extremely careful in using number-weighted distributions, as these are known to significantly blow-up the contribution of small particles. In fact, the primary data are intensity-weighed (as scattered intensity is measured) and hence the intensity-weighed distribution is most accurate. In theory, you can transform the intensity-weighted distribution to a volume- or number-based distribution. The main problem is however that your original intensity-weighed distribution is an approximation of the real distribution, whereby the obtained distribution is mostly broader than it should be. Due to the largely non-linear nature of the conversion of the intensity to the number distribution, the broadened tail towards small particles is blown up in the number distribution and apparently becomes the most important contribution. My advice: do not use these transformation, as every additional operation includes additional uncertainty on the result obtained. Hence: rather have a look for the intensity-weighed distribution !