I a currently designing a research survey and would like to use company brand names such as 'Apple' for participants to rate their preferred organisational attributes against. Is this ethical?
Yes, you can use brand names and trademarks as long as you mark them as such.
You should also, probably include a disclaimer that you have no ties to any of the companies you are researching.
But be aware that some companies are paranoid about their public image, so make sure that anything you say is supported by facts, not your opinions.
The brand names are public, by intention. You can use them. Notice that the popular press mentions brand names and trademarks constantly.