A similar application was to use aerogels, which are highly insulating but not reflective, as clothing insulation. I recall a number of companies have explored this in the past [1]. The issue with aeogels appears to be two-fold: firstly, they are relatively expensive to manufacture, but secondly, the resulting garments are often too warm!
[1] http://www.outsideonline.com/outdoor-gear/clothing-apparel/H...