Get all characters to the left of a specific character in further increasing depth VB.NET

say I have the following string:
folder1folder2folder3folder4

I need to cut the string at each slash, so I end up with:
folder
folder1folder2
folder1folder2folder3
folder1folder2folder3folder4

I tried using substring and Split(""c)(0) and that gives me "folder" but how I do now get folder1folder2, etc.?