The root cause of the Persian wars was the expansion of Persian empire into Ionia and annexation of Ionian Greek cities into the empire. That led to some discontent, and finally into the Ionian Revolt, the Burning of Sardis etc. At this point, clearly at least some of the Ionian cities resented the Persian rule.
Then, in the (second) Persian war, we know that the Persian army, and especially navy contained Ionian forces. Artemesia of Halicarnassus was one of the prominent naval commanders and consultant of Xerxes. He reportedly praised her for bravery. Also, he is said to have praised the bravery of Ionian navies over the Phoenicians during the battle of Salamis. Here, it seems that Ionian cities were pretty much loyal to Persia.
Then, at the end of second Persian wars, in the Battle of Mycale, Greeks appealed to the loyalty of Ionians, and as a result, they were stripped off their weapons by Persians because of suspicion. At this point (at least by my preliminary research), it's not clear what Ionians felt about Persians, but clearly, Persians didn't trust Ionians as much as they did at the battle of Salamis.
Afterwards, Ionians joined Athens in the Delian League whose primary stated objective was to liberate Ionian cities and take revenge on Persia.
It seems to me that the attitude of Ionians towards Persia changed a couple of times during this time. Was this genuine, or were they simply too helpless to do anything during the Persian rule?
Also, why did Persians (or more specifically, Xerxes) trust Ionians during the second invasion, even though they had revolted and shown resentment in recent past? Similarly, how did mainland Greeks view towards the changing attitudes of Ionians towards Persians? Here, I guess it's relevant that at the eve of the formation of the Delian League, when it was proposed that the Ionians should migrate to some safer place, it was opposed by he Athenians and instead, it was decided that they would help them defend their homeland.