Sorry, I am sure that is not what you want to hear.
Simlab has a plugin for Maya that will do this. This could work for you if Adobe has a PDF viewer that runs on iPhone. (3rd party PDF viewers are usually incompatible with 3D PDF)
Simlab does have viewers for Android & iPad that will use their native format instead of 3D pdf.
FYI - the DXF format does not support textures, only facet colors.
Message was edited by: Chris Dordoni
I discovered that although there is an Adobe PDF viewer for iPhone, it does not read 3D PDF files all by itself. Another app (plugin) for the iPhone is needed, go here: https://itunes.apple.com/us/app/id569307672?mt=8
When you open the 3D PDF in Adobe Reader, the other app recognizes the 3d content and displays it. From the comments on the itunes site, it appears there are some limited functions with 3D files.