I have designed an online questionnaire that could be operated through a mobile phone. I plan to spread the questionnaire through my personal network. Is this way of data collection a scientific approach?

Go go go!

You are right. Let me think about it.

It is a convenient sampling, which lacks representativeness. I am afraid that the funders may challenge your choice of data collection method unless you can prove it is the best way. In a scientific survey, samples should be selected from a well-defined population by a probability sampling method.