This is an old idea that has been in use by many designers as well as folks that like DIY and have some spare time on their hands. Sliding door, made of wood mostly, but metal elements are a frequent guests within this frame work so to speak. Door that can have a wall type functionality can be a fun project and something that brings an interesting accent into a flat.
They come in various shapes and types, from reclaimed barn wood to pallet wood and even a previously used door find their way into re purposed project. Depending on design and material used for this idea, this kind of door can be quite heavy, so bear in mind that the wall mountings must be proper and will withstand the weight. Some doors I have seen are made out of naturally looking boards, not trimmed and left to form an original pattern, this is all a matter of taste really, there is no right or wrong in here, that is a cool fact-it is all up to you.
The hardware required to fit this type of door can be purchased online, it is usually not cheap, you are looking to spend over £100 for a complete set, but there is no way around it really, unless you got a nicely fit shop that can manufacture these. Set of iron wheels, mounts and track is what you need to be able to hung these up without worrying they will squash you some Sunday morning.
Some of these can be installed in the way that would divide the room into 2 compartments, sliding option is not really the main role here, more like a decorative accent.
And when you get bored with these-take them down, fit some legs and turn it into a dining table;)