What is the intent of your research/work log? Do you just want to capture your ideas so you are able to review important TODO items, insights, and the rationale for decisions you've made later, if needed? Or is the purpose to document your work so that if you develop an important, patentable invention you have adequate documentation for a legally defensible patent? If legal defense of a patent is the intent, then consulting with an attorney about your documentation methods long before you've invented anything is the wise thing to do. My guess is that old-fashioned signed, dated, & witnessed dead-tree paper records are probably still preferred.