You can use the
:split function of vim to separate a given string to all its different character.
The basic split function that would do it for you would be something like:
A full command that would actually do the split is:
:execute "normal ciw" . string(split(expand("<cword>"), '\zs'))
If you would like, you can create a function that would change the current word to its different characters.
The function would be:
let current_word = expand("<cword>")
for current_char in split(current_word, '\zs')
execute "normal a\'" . current_char . "\', "
You can add it to your vimrc and load it when needed, or map it to a command or a set of keys.
command! SplitWord call SplitCurrentWord)