An object of the present invention is to provide a transparent heat insulating member which can maintain transparency in a high-humidity. The transparent heat insulating member according to the embodiment of the present invention is a transparent heat insulating member including a cellulose porous body, in which the cellulose porous body contains a cellulose nanofiber and a water-repellent component, and the cellulose porous body has a fiber diameter of 3 to 40 nm.

Disclosed are cellulose-based flexible gels containing cellulose nanorods, ribbons, fibers, and the like, and cellulose-enabled inorganic or polymeric composites, wherein the gels have tunable optical, heat transfer, and stiffness properties. The disclosed gels are in the form of hydrogels, organogels, liquid-crystal (LC) gels, and aerogels. Further disclosed are highly transparent and flexible cellulose nanofiber-polysiloxane composite aerogels featuring enhanced mechanical robustness, tunable optical anisotropy, and low thermal conductivity. Further disclosed are gels comprising cellulosic material derived from bacteria and processes for preparing bacterial cellulose gels and methods of use.