Air carrier Captain reported one side of the ailerons was neutral with the wing while the other side was visually one inch different on the ground. The aircraft required aileron trim in flight.

Narrative

During the takeoff; while hand flying; I observed the aircraft required aileron trim to maintain level flight; and also observed some slight 'slop' in the control wheel / aileron control - where I would move the control wheel more than usual before resistance would be felt or control response would occur. This was experienced again during approach. I decided to complete the walk-around. I ensured that all Hydraulic Systems pressurized and the aileron trim neutralized. On the walk around; I observed the right side aileron was nearly aligned with the trailing edge portion of wing inboard and outboard of the ailerons; while the left side aileron was misaligned by nearly 1 inch as compared with the trailing edge portion of wing inboard and outboard of the ailerons. Maintenance had already been contacted enroute via ACARS about servicing the #2 Hydraulic System; which had indicated 'white' fluid level in flight; at a charted quantity just 8% above minimum. I requested boarding be held temporarily until I contacted Maintenance Control. I shared regarding my concerns and asked if there was some way to identify whether this visual mismatch of the aileron position could have contributed to the flight control 'loose' or 'delayed response' yoke input anomaly. Was informed that if I still had some Aileron Trim available to use and there were no EICAS messages all seemed ok on their end. I subsequently spoke with the Chief Pilot and notified the gate agent OK to board the aircraft. Operated the aircraft to ZZZ.Cause: It is unclear what caused the 'slop;' delayed reaction in control response or misalignment of the ailerons on the walk-around; despite hydraulics being fully pressurizedI would be interested to know why this occursSuggestions: Since this is an unusual scenario and there is no required technical training for pilots on the mechanical operation of the Aileron Trim or Aileron Control channel components; perhaps some information could be disseminated in terms of how to identify when aircraft display tendencies which require attention