Sounds like you've got your answer in terms of IP, but it's also worth considering that a lot of publishers do not want to publish work which is already available for free online (at least I know this is the case for novels, not sure about comics). There are some exceptions, for instance if your series gets a good following online, this can tell a publisher that it could be profitable, though you'll likely need to take the online version down before publishing.
With that said, when it comes to comics, I think a lot of people publish independently using crowd funding, so in that case you're not beholden to a publisher, and will likely make most of your sales from people who have already read your work online.