As indicated by other answers, PDFs primary function was to be a visual representation of content and visual representation should typically be identical across different platforms / readers / devices. That was the goal of the file format and it's diametrically opposed to file formats such as XML that are all about structure.
However, in recent years PDF did get additional functionality that may help with this. PDF files now support tagging and the purpose of tagging is to add structure to the file. A PDF file that is properly tagged does know where paragraphs of text are, what are headers, what are lists etc... And that information in theory can be used to support (limited) responsiveness.
For example, see the link here (https://helpx.adobe.com/acrobat/using/reading-pdfs-reflow-accessibility-features.html) where Adobe explains how the reflow view in Acrobat Pro works. It states that Acrobat can use the tagging structure inside a PDF file (or even automatically create some semblance of tagging on the fly for documents that are not tagged) to give you a view of the PDF file adjusts itself to the available display size.
Whether or not this is going to work depends mostly on the reader technology you will be using on your mobile device and you should certainly not confuse the possibilities of this with full responsiveness where content is hidden, replaced, adjusted, repositioned etc... such as what you can accomplish with HTML and CSS on web sites.
But it is a start.
