Membrane for sticking to living organism, and method for producing same

Abstract

A cellulose membrane according to an embodiment of the present disclosure is a self-supporting cellulose membrane having a thickness of between 20 nm and 1300 nm, inclusive, composed of regenerated cellulose having a weight average molecular weight of 150,000 or more.

1 . A method for producing a membrane, the method comprising:
 (A) preparing a cellulose solution containing a first solvent containing at least an ionic liquid;   wherein   the cellulose has a weight average molecular weight of 150,000 or more;   (B) applying the cellulose solution to a surface of a substrate having a contact angle with water of 70° or less to form a liquid membrane on the surface;   (C) immersing the liquid membrane in a liquid that is not capable of dissolving cellulose; and   (D) removing the first solvent and a part other than the ionic liquid of the liquid from the liquid membrane, after the step (C).   
     
     
         2 . The method for producing a membrane according to  claim 1 , wherein
 the step (B) includes (B 1 ) preparing the substrate by subjecting a polymer material to surface modification.   
     
     
         3 . The method for producing a membrane according to  claim 1 , wherein
 the step (A) further includes (Aa) diluting the cellulose solution.   
     
     
         4 . The method for producing a membrane according to  claim 3 , wherein
 in the step (Aa), the cellulose solution is diluted by diluting a mixture of an ionic liquid, or the first solvent and the cellulose having a weight average molecular weight of 150,000 or more, in a second solvent.   
     
     
         5 . The method for producing a membrane according to  claim 1 , wherein
 a part other than the ionic liquid in the solvent contained in the cellulose solution includes an aprotic polar solvent having a SP value of 12 or more.   
     
     
         6 . The method for producing a membrane according to  claim 5 , wherein
 the aprotic polar solvent is dimethyl sulfoxide.   
     
     
         7 . The method for producing a membrane for according to  claim 1 , further comprising
 (E) heating the liquid membrane, before the step (C).   
     
     
         8 . The method for producing a membrane according to  claim 7 , wherein
 in the step (E), the liquid membrane is heated at a temperature lower than a decomposition temperature of the ionic liquid in the first solvent.   
     
     
         9 . The method for producing a membrane according to  claim 1 , further comprising step (F) of gelating the liquid membrane, after the step (B). 
     
     
         10 . The method for producing a membrane according to  claim 1 , wherein
 an anion contained in the ionic liquid is amino acid.   
     
     
         11 . The method for producing a membrane according to  claim 10 , wherein
 the amino acid has a terminal carboxyl group and a terminal amino group.   
     
     
         12 . The method for producing a membrane according to  claim 10 , wherein
 a cation contained in the ionic liquid is a quaternary ammonium cation.   
     
     
         13 . The method for producing a membrane according to  claim 1 , wherein
 in the step (C), voltage is applied to the liquid.   
     
     
         14 . The method for producing a membrane according to  claim 13 , wherein
 the voltage is lower than a voltage at which the liquid is electrolyzed.   
     
     
         15 . The method for producing a membrane according to  claim 1 , further comprising:
 (G) immersing a membrane provided in the step (D) in a solution containing a component that acts on living organism or a component that protects living organism, followed by drying.