I did some research into STF and now want to make liquid armor also. Usualy 100-1000nm silicon dioxide particles are used mixed with liquid. I think liquid could be anykind even water (beach wet sand also has STF properties), just PEG is more stable liquid - it freezes at very low temperature and boils at high so does ethylenglycol based antifreeze.
It's hard to get nanosilica in my country but there are selled 10kg bags of fumed silica 3-4 micrometer size. I wonder if that would work also fine.
Material also could be used of many kinds. Kevlar is one of most strongest but there also strong fabrics such as nylon „Zylon“, „Condura“, „Dyneema“ and futuristic nanocellulose, graphene and GMO silk.
I saw one guy making stab proof t-shirt by sooking in STF:
