Bacterial cellulose gels, process for producing and methods of use

Abstract

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

What is claimed is: 
     
         1 . An aerogel, comprising bacterial cellulose. 
     
     
         2 . The aerogel according to  claim 1 , wherein the aerogel has a thermal conductivity of from about 10 −3  W/(m·K) to about 10 W/(m·K). 
     
     
         3 . The aerogel according to  claim 1 , wherein the aerogel has a transmissivity of electromagnetic radiation of less than about 100%. 
     
     
         4 . The aerogel according to  claim 1 , wherein the aerogel has a bulk modulus of from about 1 Pa to about 10 6  Pa. 
     
     
         5 . The aerogel according to  claim 1 , wherein the bacterial cellulose is obtained from  Acetobacter hansenii, Acetobacter xylinum  or mixtures thereof. 
     
     
         6 . A cellulosic film, comprising one or more bacterial cellulose nanomaterials wherein the aerogel has a thermal conductivity of from about 10 −3  W/(m·K) to about 10 W/(m·K). 
     
     
         7 . The cellulosic film, according to  claim 6 , wherein the cellulosic film has a transmissivity of electromagnetic radiation of less than about 100%. 
     
     
         8 . The cellulosic film according to  claim 6 , wherein the cellulosic film has a thickness from about 1 μm to about 10 cm. 
     
     
         9 . The cellulosic film according to  claim 6 , wherein the cellulosic film has a bulk modulus of from about 1 Pa to about 10 6  Pa. 
     
     
         10 . The cellulosic film according to  claim 6 , wherein the bacterial cellulose is obtained from  Acetobacter hansenii, Acetobacter xylinum  or mixtures thereof. 
     
     
         11 . A process for preparing a bacterial cellulose aerogel, comprising:
 a) treating pellicles of bacterial cellulose grown in a growth media with an aqueous base to provide bacteria-free pellicles;   b) exchanging the water contained in the bacteria-free pellicles with a volatile solvent; and   c) drying the pellicles to remove the volatile solvent to form an aerogel   
     
     
         12 . The process according to  claim 11 , wherein the aerogel has a thermal conductivity of from about 10 −3  W/(m·K) to about 10 W/(m·K). 
     
     
         13 . The process according to  claim 11 , wherein the aerogel has a transmissivity of electromagnetic radiation of less than about 100%. 
     
     
         14 . The process according to  claim 11 , wherein the aerogel has a bulk modulus of from about 1 Pa to about 10 6  Pa. 
     
     
         15 . The process according to  claim 11 , wherein the bacterial cellulose is obtained from  Acetobacter hansenii, Acetobacter xylinum  or mixtures thereof. 
     
     
         16 . The process according to  claim 11 , wherein the size of the bacterial cellulose is controlled by addition of carboxymethyl cellulose to the growth media wherein the pellicles are formed.