the classic choices for outer-membrane proteins such as Porins have been octyl-pentaoxyethelene or the tetra versions also octyl-polyoxyethelene but also include beta-Octyl-clucoside.
We have had success on a number of systems using styrene maleic acid co-polymers, which remove the need for detergents. Essentially they extract the membrane protein surrounded by its native lipids with the polymer acting like a nano disc scaffold. Maybe they could help. See;
Article Detergent-free purification of ABC transporters
Article The use of SMALPs as a novel membrane protein scaffold for s...