Spider silk protein film, and method for producing same
A film of the present invention contains a polypeptide derived from spider silk proteins. The decomposition temperature of the film is 240 to 260° C. The film absorbs ultraviolet light having a wavelength of 200 to 300 nm and has a light transmittance of 85% or more at a wavelength of 400 to 780 nm. The film is transparent and colorless in a visible light region. A method for producing a film of the present invention includes: dissolving a polypeptide derived from spider silk proteins in a dimethyl sulfoxide solvent to prepare a dope; and cast-molding the dope on a surface of a base. Thus, the present invention provides a spider silk protein film that can be formed easily and has favorable stretchability, and a method for producing the same.
1. A spider silk protein film comprising a polypeptide derived from spider silk proteins,
wherein the spider silk protein film contains dimethyl sulfoxide in an amount from 0.05% to 11.2% by mass,
begins decomposition at between 240 to 260° C.,
the film absorbs ultraviolet light having a wavelength of 200 to 300 nm and has a light transmittance of 85% or more at a wavelength of 400 to 780 nm,
the film is transparent and colorless in a visible light region,
the dimethyl sulfoxide is a plasticizer, and
when the spider silk protein film is uniaxially-stretched or biaxially-stretched, the film has a maximum stress of 40 MPa to 100 MPa and a displacement at rupture point (strain) of 10 to 50%.
2. The spider silk protein film according to claim 1 , wherein the spider silk protein film has a refractive index ranging from 1.2 to 1.6 at a wavelength of 590 nm.
3. The spider silk protein film according to claim 1 , wherein the spider silk protein film has moisture absorbency and has a mass reduction of 4-8% at 67 to 94° C. in a thermo-gravimetric/differential thermal analyzer (TG-DTA).
4. The spider silk protein film according to claim 1 , wherein the spider silk protein film is colored by addition of a colorant that can dissolve or disperse in dimethyl sulfoxide.
5. The spider silk protein film according to claim 1 , wherein the protein film consists essentially of the polypeptide derived solely from spider silk proteins and the dimethyl sulfoxide.
6. A spider silk protein film, comprising:
a polypeptide derived from spider silk protein; and
a plasticizer,
wherein the plasticizer is dimethyl sulfoxide, the dimethyl sulfoxide is present in an amount from 0.05% to 11.2% by mass, and the spider silk protein film is a stretched film.
7. The spider silk protein film of claim 6 , wherein the film has a maximum stretch ratio in water of at least 1.3.
8. The spider silk protein film of claim 6 , wherein the spider silk protein film is thermally fixed.
9. The spider silk protein film of claim 6 , wherein the dimethyl sulfoxide is present in an amount between 0.05% and 1.2% by mass.
10. The spider silk protein film of claim 6 , wherein:
the film absorbs ultraviolet light having a wavelength of 200 to 300 nm and has a light transmittance of 85% or more at a wavelength of 400 to 780 nm, and
the film is transparent and colorless in a visible light region.