Sustainable multilayer biopolymer films with thermoforming capability

Abstract

In one aspect, the disclosure relates to multilayer composite films comprising a first biopolymer such as agarose, and a second biopolymer such as shellac. In the films, one or both layers may further comprise a biodegradable plasticizer. In a further aspect, the films can be flat or can be thermoformed to have a three-dimensional shape. The films are biodegradable and have very low permeability to water, gases, and other contaminants. Also disclosed are methods of making the films and consumer product packaging materials comprising the films.

Description

ATTORNEY DOCKET NO.221407-2160 SUSTAINABLE MULTILAYER BIOPOLYMER FILMS WITH THERMOFORMING CAPABILITY CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No.63 / 704,583 filed on October 8, 2024, which is incorporated herein by reference in its entirety. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] This invention was made with government support under grant number CMMI2233399 awarded by the National Science Foundation. The government has certain rights in the invention. BACKGROUND

[0003] Plastic packaging represents one of the largest market use of plastics and makes up nearly half of the plastic waste produced globally. Most of the current packaging films are non- biodegradable and contribute significantly to plastic pollution, which poses a severe environmental challenge. Only 2% of plastic waste is recycled back into packaging or other applications. The partial degradation of present conventional packaging films leads to microplastic accumulation in landfills and oceans. This persistent pollution harms wildlife, ecosystems, and human health. However, many biobased films, while more environmentally friendly, lack the necessary barrier properties to adequately protect packaged contents from moisture, oxygen, and contaminants. This shortfall limits their effectiveness and applicability, particularly in industries requiring high-performance packaging solutions, such as the food and pharmaceutical sectors. To limit environmental damage, there is a rapidly growing industrial and scientific interest to introduce alternatives for petroleum-based plastic packaging.

[0004] Among the available alternatives, biopolymers derived from natural and sustainable resources represent an attractive option to replace conventional petroleum-sourced polymers. These biobased polymers provide environmental advantages, sustainability, and biodegradability. However, performance limitations and high production costs have hindered the widespread use of these polymers, restricting them to certain niche markets that currently represent less than 1% of the plastics market. For biopolymers to secure their foothold in the market, several shortcomings must be tackled such as high water and oxygen permeability, mechanical brittleness, thermal stability, water uptake, and instability during processing. Furthermore, typical biopolymer films lack thermoformability and lack heat-sealing capabilities which enable convenient manufacture of packaging products.ATTORNEY DOCKET NO.221407-2160

[0005] Despite advances in biopolymer film research, there is still a scarcity of film compositions that are biodegradable, mechanically robust, thermoformable, and heat-sealable while also effectively providing a barrier against moisture, oxygen, and the like. These needs and other needs are satisfied by the present disclosure. SUMMARY

[0006] In accordance with the purpose(s) of the present disclosure, as embodied and broadly described herein, the disclosure, in one aspect, relates to multilayer composite films comprising a first biopolymer such as agarose, and a second biopolymer such as shellac. In the films, one or both layers may further comprise a biodegradable plasticizer. In a further aspect, the films can be flat or can be thermoformed to have a three-dimensional shape. The films are biodegradable and have very low permeability to water, gases, and other contaminants. Also disclosed are methods of making the films and consumer product packaging materials comprising the films.

[0007] Other systems, methods, features, and advantages of the present disclosure will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the present disclosure, and be protected by the accompanying claims. In addition, all optional and preferred features and modifications of the described embodiments are usable in all aspects of the disclosure taught herein. Furthermore, the individual features of the dependent claims, as well as all optional and preferred features and modifications of the described embodiments are combinable and interchangeable with one another. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

[0009] FIG. 1 shows a design strategy for making multilayer biopolymer films. (GRAS: Generally recognized as safe).

[0010] FIG.2A shows an optical image of an AG / Sh P film and FIG.2B shows transmittance through a control agarose film and AG / Sh U film in the UV-vis region. (See Table 1 in the Examples for experimental conditions for these samples.)ATTORNEY DOCKET NO.221407-2160

[0011] FIG.3 shows water contact angle of agarose and shellac layers of an AG / Sh P bilayer film.

[0012] FIG.4 shows tensile stress / strain curves of a single layer of agarose film and an AG / Sh P bilayer film.

[0013] FIG.5 shows a demonstration of water barrier property of the AG / Sh P bilayer film.

[0014] FIG.6 shows an example of a small pouch made from a heat-sealed bilayer film that can hold water for extended periods.

[0015] FIG.7A shows cylindrical, cuboid, and pyramid shapes made by heat sealing Bilayer P films (see Table 2 for description of Bilayer P). FIG.7B shows a cylindrical container made of Bilayer P film contains 5 mL water. FIG.7C shows two Bilayer P films (joined by heat sealing) before and after tensile testing. FIG.7D shows a corresponding tensile stress-strain diagram for the joined films.

[0016] FIG.8 shows an example of a possible configuration of a multilayer barrier film based on shellac and other biopolymers.

[0017] FIGs.9A-9C show (FIG.9A) tensile strength, (FIG.9B) elongation at break, and (FIG. 9C) Young’s moduli of the control and barrier films made by rod spreading.

[0018] FIG. 10 shows water vapor transmission rate of the barrier films made by rod spreading.

[0019] Additional advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or can be learned by practice of the invention. The advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. DETAILED DESCRIPTION

[0020] Disclosed herein is a new type of multilayer film using agarose and shellac biopolymers, designed specifically for use as environmentally friendly food and other consumer product packaging materials. In one aspect, agarose, derived from seaweed, is known for its gel-forming ability and finds use in biomaterials due to its strength and transparency. In another aspect, shellac, a natural resin from the lac bug, offers excellent moisture and gas barrier properties, making it suitable for various applications including food coatings and pharmaceuticals. In a further aspect, combining agarose and shellac in multilayer films maximizes the range of their useful properties: agarose provides mechanical integrityATTORNEY DOCKET NO.221407-2160 and flexibility, while shellac enhances durability and barrier capabilities. In yet another aspect, shellac's thermoplastic nature allows films with top shellac layers to be thermoformed into custom shapes, ideal for tailored packaging solutions. In an aspect, the multilayer films can be made through a simple solution-casting method.

[0021] The disclosed biopolymer-based films can be prepared by solution casting. These biopolymer films are thermoformable and heat-sealable and mechanically outperform most of the common present bio-based packaging materials that face major problems due to fragility and increased water uptake. The films are also much less water vapor and oxygen permeable compared to most current biopolymer films. The completely natural, sustainable, and biodegradable components as well as the excellent mechanical and optical properties of these films can lead to their commercial use as sustainable packaging alternatives.

[0022] A diagram showing an exemplary fabrication process for the disclosed material is presented in FIG.1. In an aspect, multilayer packaging can integrate the merits of individual polymer layers offering mechanical robustness and superior barrier properties. Further in this aspect, agarose layers provide mechanical strength and flexibility, while shellac offers superior barrier properties and durability. In one aspect, and without wishing to be bound by theory, although shellac does not have good film-forming properties on its own, it can be used effectively as a coating or an overlayer on agarose.

[0023] Agarose, a polysaccharide derived from seaweed, is known for its gel-forming capabilities and its use in biomedical applications such as tissue engineering and drug delivery. Its molecular structure provides a robust framework for film formation, offering high tensile strength and transparency. Additionally, agarose is non-toxic and exhibits excellent film-forming properties, making it suitable for forming the core of sustainable polymer replacement films. It makes films with excellent mechanical and optical properties, which, however, are sensitive to water.

[0024] Shellac is a natural resin secreted by the female lac bug (Kerria lacca). It has been used historically in various applications, ranging from food coatings to pharmaceutical tablets. Shellac is known for its excellent barrier properties against moisture and gases, its glossy finish, and its ability to form coatings that are impermeable and protective. Moreover, shellac is recognized for its biodegradability and non-toxic nature, aligning well with the growing demand for environmentally friendly materials.

[0025] In one aspect, in addition to low permeability, the disclosed films possess the features of thermoforming and themosealing. In an aspect, thermoforming is widely used in food packaging as a thermoplastic polymer sheet-forming processing due to its ease of operation,ATTORNEY DOCKET NO.221407-2160 low cost, and high speed. In a further aspect, since shellac is a thermoplastic material, it has thermoforming capability. In yet another aspect, when heated, shellac becomes malleable and can be molded into various shapes, making it suitable for creating custom packaging films. In one aspect, the disclosed films are optically translucent have good water, moisture, and oxygen barrier properties compared to most biobased materials. In yet another aspect, based on the thermoforming capability of shellac, the formation of 3D structures has been demonstrated which opens the possibility of the multilayer packaging films to be used in different forms and applications. In a still further aspect, the heat-sealing capability and other properties of agarose and shellac finds applications in commercializing biobased packaging materials. Composite Films In one aspect, disclosed herein is a composite film having one or more layers including a first biodegradable polymer in contact with one or more layers including a second biodegradable polymer. In an aspect, the first biodegradable polymer can be selected from agarose, chitosan, sodium alginate, polycaprolactone (PCL), polylactic acid (PLA), a derivative thereof, or any combination thereof. In one aspect, the first biodegradable polymer is agarose. In another aspect, the second biodegradable polymer is shellac. In one aspect, in the composite film, the one or more layers including the second biodegradable polymer is continuous and contacts an entire surface of the one or more layers including the first biodegradable polymer. In an alternative aspect, the one or more layers including the second biodegradable polymer is discontinuous and contacts a portion including less than an entire surface of the one or more layers comprising the first biodegradable polymer. Further in this aspect, when the layer including the second biodegradable polymer is discontinuous, the layer(s) including the second biodegradable polymer can contact about 10% (area / area), about 20%, 30%, 40%, 50%, 60%, 70%, 80%, or about 90% of the surface area of the layer(s) including the first biodegradable polymer. Still further in this aspect, since biodegradable polymers such as shellac have thermoforming capability, films prepared according to this aspect can use the shellac as a sealing mechanism in commercial packaging as a replacement for glue.

[0026] In one aspect, the biopolymers can be natural (e.g. chitosan, sodium alginate, etc.) or synthetic (PCL, PLA). In one aspect, mechanical properties of the films can be changed by substituting all or a portion of the agarose with another polymer having high tensile strength and / or good adhesion to the shellac layer. In one aspect, thickness of a shellac layer can be controlled by changing the shellac concentration, Mayer Rod number, or rate of casting. In one exemplary aspect, 40% (w / v) shellac solution was used to prepare 50 micrometer thickness of shellac coating with each Mayer Rod spreading (Mayer Rod #78). Based on theATTORNEY DOCKET NO.221407-2160 Mayer Rod number and solution concentration, each count of spreading can create thickness in the range of from about 10 μm to about 100 μm, or of about 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100 μm.

[0027] In some aspects, the composite film can also include one or more layers including a third biodegradable polymer such as, for example, agarose, chitosan, sodium alginate, polycaprolactone (PCL), polylactic acid (PLA), a derivative thereof, or any combination thereof. In one aspect, the third biodegradable polymer is different from the first biodegradable polymer or the second biodegradable polymer, or both. In an aspect, the third biodegradable polymer is chitosan.

[0028] In any of these aspects, the one or more layers including the first, second, or third biodegradable polymer, if present, can further include a plasticizer. In one aspect, the plasticizer is biodegradable. In another aspect, the plasticizer can be glycerol, polyethylene glycol (PEG), or any combination thereof.

[0029] In some aspects, the one or more layers with the first biodegradable polymer contain a glycerol plasticizer. In one exemplary aspect, in such a layer, agarose and glycerol are present in a ratio of from about 1:1 (w / w) to about 1:0.20 (w / w), or about 1:1, 1:0.80, 1:0.60, 1:0.40, or about 1:0.20 (w / w). In one aspect, the ratio is about 1:1 (w / w). In another aspect, the one or more layers with the second biodegradable polymer contain PEG. In a further aspect, the PEG can be PEG 200, PEG400, PEG4000, or any combination thereof. Further in this aspect, the shellac and the PEG can be present in a ratio of from about 1:0.20 (w / w) to about 1:0.05 (w / w), or of about 1:0.20, 1:0.15, 1:0.10, or about 1:0.05 (w / w). In an aspect, the ratio is about 1:0.10 (w / w). In an alternative aspect, the second biodegradable polymer layer does not include a plasticizer. In any of these aspects, the agarose and shellac can be present in the film in a ratio of from about 1:20 (w / w) to about 1:1 (w / w), or at about 1:20, 1:19, 1:18, 1:17, 1:16, 1:15, 1:14, 1:13, 1:12, 1:11, 1:10, 1:9, 1:8, 1:7, 1:6, 1:5, 1:4, 1:3, 1:2, or about 1:1 (w / w). In one aspect, the ratio is about 1:5 (w / w).

[0030] In one aspect, the composite film can be flat. In an aspect, at least one of the one or more layers is a thermoplastic layer. In a further aspect, the thermoplastic layer can be the layer including shellac. In some aspects, the thermoplastic layer is on an outward-facing surface of the film. Further in this aspect, the thermoplastic layer can be bonded to a thermoplastic layer of a second composite film. In an aspect, and without wishing to be bound by theory, the inclusion of a thermoplastic layer and / or thermoplastic biopolymer allows for thermaformability and / or heat-sealing capabilities in the disclosed films. In another aspect, the composite film can be thermoformed to have a three-dimensional shape such as, for example, a cube, cylinder, tetrahedron, pouch, or any combination thereof. In a further aspect, theATTORNEY DOCKET NO.221407-2160 thermoformed films can be heat sealed to form a permanent sealed bond between layers of the films. In some aspects, the second biopolymer, such as, for example, shellac can be applied to part of the first biopolymer layer but not the complete biopolymer layer. In any of these aspects, the composite film is biodegradable. In a further aspect, the composite film can be optically translucent. In one aspect, the composite film can have a transmittance of from about 65% to about 85% between about 380 nm and 700 nm (i.e., the visible wavelength range), or of about 65, 70, 75, 80, or about 85%.

[0031] Although biolayer films are contemplated and disclosed, in some aspects, films with more than two layers can also be produced. In one aspect, disclosed herein is a composite film having a plurality of layers including the first biodegradable polymer and a plurality of layers including the second biodegradable polymer, wherein individual members of the plurality of layers comprising the first biodegradable polymer alternate with individual members of the plurality of layers comprising the second biodegradable polymer. In another aspect, a layer with the first biodegradable polymer can be sandwiched between two individual layers with the second biodegradable polymer.

[0032] In one aspect, the composite film has a water contact angle of from about 65° to about 100°, from about 65° to about 85°, or from about 75° to about 85°, or greater than 85°, or at least about 65, 70,75, 80, or 85°, or a combination of any of the foregoing values, or a range encompassing any of the foregoing values. In another aspect, the composite film has a tensile strength of from about 1 MPa to about 45 MPa, or from about 3.4 MPa to about 11.2 MPa, or from about 5 MPa to about 11.2 MPa, or from about 10 MPa to about 11.2 MPa, or of greater than 11.2 MPa, or of about 1, 2, 3, 4, 5, 7.5, 10, 15, 20, 25, 30, 35, 40, or about 45 MPa, or a combination of any of the foregoing values, or a range encompassing any of the foregoing values. In still another aspect, the composite film has an elongation at break of from about 5% to about 50%, or of from about 25% to about 35%, or of from about 27.5% to about 35%, or from about 30% to about 35%, or greater than 35%, or of about 5, 10, 15, 20, 25, 30, 35, 40, 45, or about 50%, or a combination of any of the foregoing values, or a range encompassing any of the foregoing values. In still another aspect, the composite film develops an increase in weight after 24 hours of immersion in water of from about 10% to about 100%, or of less than about 50%, less than about 40%, less than about 30%, less than about 20%, or less than about 10%. In another aspect, the composite film has very low permeability or is substantially impermeable to water, oxygen, bacteria, fungi, or any combination thereof.

[0033] In a further aspect, the aforementioned properties can be tuned. In one aspect, optical transmittance can be tuned based on film composition. In a further aspect, changing the concentration of either glycerol or PEG, or both, or increasing the thickness of the secondATTORNEY DOCKET NO.221407-2160 biopolymer layer can alter the optical transmittance of the film. In another aspect, barrier layers such as water vapor permeability or oxygen permeability can be improved by increasing the shellac thickness or the number of layers in the films. In another aspect, barrier properties can further be tuned by the incorporation of biodegradable waxes or similar materials. In another aspect, the mechanical properties including tensile strength and stretchability can be improved by varying the plasticizer ratios. In another aspect, the heat-sealing properties of the films could be enhanced by including thicker surface layers and / or patterned surface layers. Consumer Product Packages

[0034] In one aspect, disclosed herein is a consumer product package including the disclosed composite film. In another aspect, the film can be coated on another packaging material such as paper. In a further aspect, the package can contain a food product, a pharmaceutical product, an agricultural product, a household product, an office product, a detergent pouch, a personal care product, wrapping for a pallet, or a protective cover. In some aspects, the composite film can be used as a seal between two layers of another material such as, for example, paper. In one aspect, the seal can be a heat seal or heat-activated seal. In some aspects, the disclosed films, when used as heat seals or other seals, can take the place of glues that may not be biodegradable or are otherwise difficult to produce. Method for Making a Composite Film

[0035] In one aspect also disclosed herein are methods for making the composite films, the methods including at least the following steps: (a) forming a first biopolymer solution comprising a first biopolymer and a first solvent; (b) solution casting the first biopolymer solution to form a first biopolymer layer and drying the first biopolymer layer; (c) forming a second biopolymer solution comprising a second biopolymer and a second solvent; (d) applying the second biopolymer solution to at least one side of the first biopolymer layer to form a second biopolymer layer and drying the second biopolymer layer to form the composite film.

[0036] In one aspect, the second biopolymer solution can be applied using solution casting, bar coating, doctor blading, injection molding, shaped extrusion, or any combination thereof. In one aspect, when bar coating is used, shellac layer manufacturing and / or coating time can be reduced by conducting the process at elevated temperatures. In an aspect, using MayerATTORNEY DOCKET NO.221407-2160 rods of different sizes, the thickness of the deposited shellac layers can be controlled effectively.

[0037] In an aspect, the first biopolymer solution can include from about 1% (w / v) to about 4% (w / v), or about 1% (w / v) of the first biopolymer, while the second biopolymer solution can include about 5% (w / v) to about 50% (w / v), or about 10% (w / v) of the second biopolymer. In one aspect, the thickness of one or both of the biopolymer layers can be altered by changing the concentration of the biopolymer or the volume of solution casting. For example, a thicker layer of shellac can be produced by increasing the concentration of shellac in the second solution.

[0038] In one aspect, the first biopolymer can be selected from agarose, chitosan, sodium alginate, polycaprolactone (PCL), polylactic acid (PLA), other biopolymer, a derivative thereof, or any combination thereof. In one aspect, the first biopolymer is agarose and the first solvent is water. In another aspect, the second biopolymer is shellac and the second solvent is ethanol.

[0039] In any of these aspects, the first biopolymer solution, the second biopolymer solution, or both the first and second biopolymer solutions contain a plasticizer. In one aspect, the plasticizer can be selected from glycerol, polyethylene glycol (PEG), or a combination thereof. In an aspect, the first biopolymer solution includes glycerol. In a further aspect, the ratio of the agarose and glycerol is from about 1:1 (w / w) to about 1:0.20 (w / w), or is about 1:1 (w / w). In another aspect, the second biopolymer solution includes PEG, such as PEG200, PEG400, PEG4000, or any combination thereof. In a further aspect, the ratio of the shellac and PEG400 is about 1:0.20 (w / w) to about 1:0.05 (w / w), or is about 1:0.1 (w / w).

[0040] In one aspect, the method further includes repeating steps (a)-(d) one or more times to form a multilayered composite film. Further in this aspect, the multilayered composite film can include alternating layers of the first biopolymer and the second biopolymer.

[0041] Many modifications and other embodiments disclosed herein will come to mind to one skilled in the art to which the disclosed compositions and methods pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the disclosures are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. The skilled artisan will recognize many variants and adaptations of the aspects described herein. These variants and adaptations are intended to be included in the teachings of this disclosure and to be encompassed by the claims herein.ATTORNEY DOCKET NO.221407-2160

[0042] Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

[0043] As will be apparent to those of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the present disclosure.

[0044] Any recited method can be carried out in the order of events recited or in any other order that is logically possible. That is, unless otherwise expressly stated, it is in no way intended that any method or aspect set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not specifically state in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including matters of logic with respect to arrangement of steps or operational flow, plain meaning derived from grammatical organization or punctuation, or the number or type of aspects described in the specification.

[0045] All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and / or materials in connection with which the publications are cited. The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided herein can be different from the actual publication dates, which can require independent confirmation.

[0046] While aspects of the present disclosure can be described and claimed in a particular statutory class, such as the system statutory class, this is for convenience only and one of skill in the art will understand that each aspect of the present disclosure can be described and claimed in any statutory class.

[0047] It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosed compositions and methods belong. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and should not be interpreted in an idealized or overly formal sense unless expressly defined herein.ATTORNEY DOCKET NO.221407-2160

[0048] Prior to describing the various aspects of the present disclosure, the following definitions are provided and should be used unless otherwise indicated. Additional terms may be defined elsewhere in the present disclosure. Definitions

[0049] As used herein, “comprising” is to be interpreted as specifying the presence of the stated features, integers, steps, or components as referred to, but does not preclude the presence or addition of one or more features, integers, steps, or components, or groups thereof. Moreover, each of the terms “by”, “comprising,” “comprises”, “comprised of,” “including,” “includes,” “included,” “involving,” “involves,” “involved,” and “such as” are used in their open, non-limiting sense and may be used interchangeably. Further, the term “comprising” is intended to include examples and aspects encompassed by the terms “consisting essentially of” and “consisting of.” Similarly, the term “consisting essentially of” is intended to include examples encompassed by the term “consisting of.

[0050] As used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a biopolymer,” “a plasticizer,” or “a layer,” includes, but is not limited to, mixtures, combinations, or series of two or more such biopolymers, plasticizers, or layers, and the like.

[0051] It should be noted that ratios, concentrations, amounts, and other numerical data can be expressed herein in a range format. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. It is also understood that there are a number of values disclosed herein, and that each value is also herein disclosed as “about” that particular value in addition to the value itself. For example, if the value “10” is disclosed, then “about 10” is also disclosed. Ranges can be expressed herein as from “about” one particular value, and / or to “about” another particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms a further aspect. For example, if the value “about 10” is disclosed, then “10” is also disclosed.

[0052] When a range is expressed, a further aspect includes from the one particular value and / or to the other particular value. For example, where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the disclosure, e.g. the phrase “x to y” includes the range from ‘x’ to ‘y’ as well as the range greater than ‘x’ and less than ‘y’. The range can also be expressed as an upper limit, e.g. ‘about x, y, z, or less’ and should be interpreted to include the specific ranges of ‘about x’, ‘about y’, and ‘about z’ as well as the ranges of ‘less than x’, less than y’, and ‘less than z’. Likewise, theATTORNEY DOCKET NO.221407-2160 phrase ‘about x, y, z, or greater’ should be interpreted to include the specific ranges of ‘about x’, ‘about y’, and ‘about z’ as well as the ranges of ‘greater than x’, greater than y’, and ‘greater than z’. In addition, the phrase “about ‘x’ to ‘y’”, where ‘x’ and ‘y’ are numerical values, includes “about ‘x’ to about ‘y’”.

[0053] It is to be understood that such a range format is used for convenience and brevity, and thus, should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. To illustrate, a numerical range of “about 0.1% to 5%” should be interpreted to include not only the explicitly recited values of about 0.1% to about 5%, but also include individual values (e.g., about 1%, about 2%, about 3%, and about 4%) and the sub-ranges (e.g., about 0.5% to about 1.1%; about 5% to about 2.4%; about 0.5% to about 3.2%, and about 0.5% to about 4.4%, and other possible sub-ranges) within the indicated range.

[0054] As used herein, the terms “about,” “approximate,” “at or about,” and “substantially” mean that the amount or value in question can be the exact value or a value that provides equivalent results or effects as recited in the claims or taught herein. That is, it is understood that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but may be approximate and / or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art such that equivalent results or effects are obtained. In some circumstances, the value that provides equivalent results or effects cannot be reasonably determined. In such cases, it is generally understood, as used herein, that “about” and “at or about” mean the nominal value indicated ±10% variation unless otherwise indicated or inferred. In general, an amount, size, formulation, parameter or other quantity or characteristic is “about,” “approximate,” or “at or about” whether or not expressly stated to be such. It is understood that where “about,” “approximate,” or “at or about” is used before a quantitative value, the parameter also includes the specific quantitative value itself, unless specifically stated otherwise.

[0055] As used herein, the terms “optional” or “optionally” means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

[0056] Unless otherwise specified, temperatures referred to herein are based on atmospheric pressure (i.e. one atmosphere).

[0057] Now having described the aspects of the present disclosure, in general, the followingATTORNEY DOCKET NO.221407-2160 Examples describe some additional aspects of the present disclosure. While aspects of the present disclosure are described in connection with the following examples and the corresponding text and figures, there is no intent to limit aspects of the present disclosure to this description. On the contrary, the intent is to cover all alternatives, modifications, and equivalents included within the spirit and scope of the present disclosure. EXAMPLES

[0058] The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how the compounds, compositions, articles, devices and / or methods claimed herein are made and evaluated, and are intended to be purely exemplary of the disclosure and are not intended to limit the scope of what the inventors regard as their disclosure. Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperature, etc.), but some errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, temperature is in °C or is at ambient temperature, and pressure is at or near atmospheric. Example 1: Materials and Methods Materials

[0059] Molecular biology grade agarose (AG, BioReagent, molecular biology grade, low EEO, Sigma Aldrich, USA) produced from marine algae were purchased from Sigma Aldrich. Dewaxed orange shellac flakes (8 oz) were purchased from WellerMart. PEG 400, and glycerol was purchased from Fisher Scientific, USA. Deionized water from a Millipore vacuum filtration system was used for all experiments. All reagents were used as received. Preparation of bilayer and multilayered films

[0060] The agarose / shellac films were prepared using the solution casting method. First, 1% (w / v) agarose solution was prepared by heating 0.2 g of agarose powder in 20 mL deionized water at 215 °C for 10 min on a magnetic stirrer (250 rpm). Then glycerol was mixed with the 1% (w / v) agarose solution on the magnetic stirrer (250 rpm) at a ratio of 1:1. The solution was then stirred until it became homogeneous. After cooling the solution to ^ 60 °C, the cooled solution was cast on square-shaped polystyrene Petri dishes with sides of 100 mm (100 × 15 mm). The solutions in the Petri dishes were left to dry on the workbench at room temperature (20 °C and ~50% relative humidity) for 2 days. A 10% solution of shellac was prepared by dissolving shellac flakes in ethanol by magnetic stirring at 350 rpm for 24 hours in room temperature. Then, the shellac ethanol solutions were centrifuged at 4400 rpm for 10 minutes to remove excess insoluble matter. The supernatant was then passed through a 0.45 μm filter to remove a small amount of insoluble matter. To make a bilayer film, shellac solution wasATTORNEY DOCKET NO.221407-2160 cast on the dried agarose film with an agarose / shellac ratio of 1:5. The cast solution was dried at 40 °C for 2 days in an oven and then the bilayer film was peeled off. In the case of preparing a plasticized shellac layer, PEG 400 was added to the shellac solution at a concentration of 10% of shellac weight before casting onto the dried agarose layer. For preparing trilayers, the peeled-off bilayer film was flipped, and shellac solution was cast on the agarose layer to get the shellac layer on both sides of the agarose layer. Using this method, multiple layers of agarose and shellac can be prepared. In this text, the films are designated as follows. Table 1: Experimental and Control Films Abbreviation Description Agarose: Shellac: Agarose: l l PE h ll cOptical properties

[0061] The UV-Vis spectrum was recorded utilizing a UV-Vis spectrophotometer (JASCO V- 550), covering wavelengths from 200 to 800 nm. Water contact angle

[0062] For static contact angle measurements, DI water was used as probe liquid. A contact angle goniometer (Ramé-hart Instrument Co., Model 200-U1) was utilized to determine contact angles at room temperature, with an 8 µL ink droplet applied and images captured 10 seconds after contact with the film surface. Mechanical evaluation

[0063] The tensile tests were carried out using the Instron 5943 instrument to measure the tensile stress and strain. The films were cut into the shape of 5 cm × 1.5 cm. The films were mounted to the large grips of the equipment. The initial length, width, and thickness of the films were recorded. The film was stretched at the strain rate of 1 mm / min by moving the top gripper handle. The experiment was stopped when the films broke in the middle. All the measurements were performed at room temperature. Degree of swellingATTORNEY DOCKET NO.221407-2160

[0064] The ambient weight (W1) of the agarose / shellac bilayer film was measured. The film was immersed in 100 ml of deionized water for 24 h which was placed at room temperature. The swelled film was taken out from the water, and the excess surface water on the film was removed using a Kimwipe. The corresponding weight (W2) was measured. The degree of swelling (%) was calculated using the equation: Degree of swelling (%) = 100% (1) Example 3: Results andOptical properties

[0065] FIG. 2A shows an optical image of an AG / Sh P bilayer film demonstrating the translucency of the bilayer film. The optical transmittance of the agarose control film and an AG / Sh U film is demonstrated in FIG. 2B. The control film has high optical transparency. However, the addition of a shellac layer reduces the transmittance of the bilayer film because of its distinguishing color. For example, the transmittance values at the wavelength of 550 nm are 90.7% and 39.7% for the agarose control film and AG / Sh U film, respectively. Water contact angle

[0066] The water contact angle on both surfaces of an AG / Sh P film is presented in FIG.3. As expected, the shellac layer shows high water contact angle of 84.9°. On the other hand, the agarose layer shows a water contact angle of 67.5°. In a previous study, the water contact angle of the standalone control film was found to be 55°. Some degree of molecular spreading from the more hydrophobic shellac layer might be responsible for increasing the water contact angle of the agarose layer. Mechanical properties

[0067] Tensile tests were performed to evaluate the mechanical properties of the agarose / shellac bilayer films, as shown in FIG.4. The control agarose film has an ultimate tensile strength of 11.2 MPa. It can be seen that the incorporation of the plasticized shellac layer reduced the tensile stress, imparting softness to the film. By adding the shellac layer (plasticized with PEG 400) with an agarose / shellac ratio of 1:5, the tensile stress reduced from 11.2 MPa to 3.4 MPa. However, no significant change was observed in the stretchability of the films as the elongation at break only changed from 30.5% to 27.5%. Degree of swelling and water barrier property

[0068] To investigate the water absorption behavior of the agarose / shellac bilayer films, their corresponding change in weight after being immersed in water for 24 hours was measured. ItATTORNEY DOCKET NO.221407-2160 was found that a 48% increase in weight occurred due to swelling. This is primarily due to the water absorption by the hydrophilic agarose layer. The control agarose film had a higher water absorption value of around 340%. Consequently, the control film became very soft and easily breakable in nature. This demonstrates the improved ability of the bilayer films as a good water barrier film. To visually demonstrate the water barrier property, an AG / Sh P bilayer film was placed over a 20 ml glass tube. Water was continuously poured onto the film for 1 minute to observe whether the film would have water permeability as shown in FIG.5. No water was observed to go into the tube demonstrating the superior water barrier property of the film. Thermoforming

[0069] Due to the thermoforming capability of shellac, the prepared bilayer films can be molded in shapes and pouches for different applications. To visually demonstrate the thermoforming capability, an AG / Sh P bilayer film was heat pressed using a 12-inch impulse heat sealer from Yeler. The film was molded into the shape of a small pouch as shown in FIG. 6. To illustrate the thermoforming capability and water barrier property at the same time, around 5 mL of water was placed inside the pouch. After 24 hours, no leakage of water was observed from the bilayer film pouch, and the liquid was contained inside. This shows promising potential for using these films in packaging and other applications as barrier films while thermoforming them in pouches and other types of containers. The shape can then be locked and closed by heat sealing. FIG. 7 shows examples of various three-dimensional shapes made from AG / Sh P bilayer films, such as cuboid, tetrahedral, and cylindrical shapes, taking advantage of the thermoforming capabilities of the composite. Alternative method for film preparation

[0070] The shellac layers in the films can also be prepared through bar coating technique. In this alternative method for preparation, Mayer rods with different sizes can be used to spread shellac layers of varying thickness. The first underlying agarose layer was prepared using the solution casting method, as discussed in the previous preparation section, with an agarose- to-glycerol ratio of 1:0.5. A 40% solution of shellac was prepared as described in the preparation section. To make a bilayer film, shellac coating was applied and spread over the agarose layer with the Mayer applicator rod #78. The coating was dried at 40 °C for 4 hours in an oven, and then the bilayer film was peeled off. For preparing trilayer films, the peeled-off bilayer film was flipped, and a shellac solution was spread on the agarose layer to obtain a shellac layer on both sides. The bilayer and trilayer films coated with shellac had an overall film thickness of ~150 µm. The films made through this method are designated as shown in Table 2:ATTORNEY DOCKET NO.221407-2160 Table 2: Films Prepared by Alternative Method Description Properties Control Plasticized control film with agarose / glycerol ratio of 1:0.5 .5 .5 io

[0071] Tensile tests were performed to evaluate the mechanical properties of the agarose / shellac bilayer and trilayer films, as shown in FIGs.9A-9C. The control film had a tensile strength of 33.4 MPa and a stretchability of 18.3%. The Bilayer UP film was very brittle, with low tensile strength and stretchability of 8.9 MPa and 8.1%, respectively. The incorporation of PEG 400 in the shellac layer reduced the tensile stress and imparted stretchability in the structure. The Bilayer P film had a tensile strength of 11.7 MPa and stretchability of 35.3%. The Trilayer P film had a lower tensile strength of 8.4 MPa and a higher stretchability of 39%. The Young’s modulus of the control film was 866 MPa. With the presence of PEG 400 plasticizer, Young’s modulus decreased. The Bilayer P and Trilayer P had Young’s modulus of 258.5 and 167.6 MPa, respectively. Water vapor transmissivity

[0072] The water vapor transmission rate (WVTR) of the prepared films was measured according to the ASTM E96 standard. The samples were placed in an environmental chamber with a temperature of 23 °C and 50% relative humidity. Under these conditions, the WVTR values are presented in FIG.10. The control film had a high WVTR of 797 g m-2day-1. After incorporating shellac layers, the WVTR values decreased significantly. The Bilayer UP and Bilayer P films had WVTR of 29.3 and 30.2 g m-2day-1, respectively. The trilayer film exhibited the lowest WVTR value of 27.8 g m-2day-1, indicating that increasing the number of layers, despite maintaining similar thickness, can significantly enhance the water vapor barrier property. WVTR could also be decreased by reducing the concentration of plasticizers in the film. Thermoforming property

[0073] The prepared films can be heat-pressed using a heat sealer to prepare different shaped model packages and objects. FIG.7A shows the 3D cylindrical, cuboid, and pyramid shapes prepared by heat-pressing Bilayer P films. The formation of various shapes demonstrates a wide range of possible applications. As demonstrated in FIG.7B, a measuringATTORNEY DOCKET NO.221407-2160 cylinder was made, and 5 ml of water was placed in it without any leakage, showing its efficiency as a container. To further investigate the heat-sealing capability of the films, two Bilayer P films were joined at specific lengths by heat-pressing, as shown in the inset of FIG. 7C. The heat-sealed film was placed in a tensile testing setup to determine its point of break. Under stress, the heat-sealed area stayed intact, and the break point was at the end of the sealed zone, showing the strength of the seal. FIG.7D shows the tensile stress / strain of the corresponding heat-sealed Bilayer P film. As seen in the figure, the tensile strength was ~12 MPa, matching the original Bilayer P film (11.7 MPa). The corresponding Young’s modulus was found to be 541.5 MPa, which was twice that of the original films. In an aspect, Young’s modulus can vary based on the thickness and length of the joined area. This demonstrates that the prepared layered films can be molded to different shapes without affecting their tensile strength while increasing the Young’s modulus. When heat-sealing is used to meld or join layered films, the Young’s moduli of the films can be significantly increased without affecting tensile strength.

[0074] It should be emphasized that the above-described embodiments of the present disclosure are merely possible examples of implementations set forth for a clear understanding of the principles of the disclosure. Many variations and modifications may be made to the above-described embodiment(s) without departing substantially from the spirit and principles of the disclosure. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims. REFERENCES 1. Ahuja, A, et al, “Shellac: From Isolation to Modification and Its Untapped Potential in the Packaging Application,” Sustainability, vol. 15, no. 4, p. 3110, Feb. 2023, doi: 10.3390 / su15043110. 2. Bang, RS, et al, “Fluid Flow Templating of Polymeric Soft Matter with Diverse Morphologies,” Advanced Materials, vol. 35, no. 16, p. 2211438, Apr. 2023, doi: 10.1002 / adma.202211438. 3. Dirpan, A, et al, “A Review on Biopolymer-Based Biodegradable Film for Food Packaging: Trends over the Last Decade and Future Research,” Polymers, vol.15, no.13, p.2781, Jun.2023, doi: 10.3390 / polym15132781. 4. Freudenthaler, PJ, et al, “Polypropylene Post-Consumer Recyclate Compounds for Thermoforming Packaging Applications,” Polymers, vol.15, no.2, Art. no.2, Jan.2023, doi: 10.3390 / polym15020345.ATTORNEY DOCKET NO.221407-2160 Giménez, E, et al, “Uniaxial tensile behavior and thermoforming characteristics of high barrier EVOH-based blends of interest in food packaging,” Polymer Engineering & Science, vol.44, no.3, pp.598–608, 2004, doi: 10.1002 / pen.20054. Kotb, Y, et al, “Hierarchically reinforced biopolymer composite films as multifunctional plastics substitute,” Cell Reports Physical Science, vol.4, no.12, p.101732, Dec.2023, doi: 10.1016 / j.xcrp.2023.101732. Liu, Y, et al, “Sustainable Soft Electronics Combining Recyclable Metal Nanowire Circuits and Biodegradable Gel Film Substrates,” Adv Elect Materials, p.2300792, Jan.2024, doi: 10.1002 / aelm.202300792. Ncube, LK, et al, “Environmental Impact of Food Packaging Materials: A Review of Contemporary Development from Conventional Plastics to Polylactic Acid Based Materials,” Materials, vol.13, no.21, Art. no.21, Jan.2020, doi: 10.3390 / ma13214994. Phelan, A, et al, “Plastic pollution and packaging: Corporate commitments and actions from the food and beverage sector,” Journal of Cleaner Production, vol.331, p.129827, Jan.2022, doi: 10.1016 / j.jclepro.2021.129827. Roh, S, et al, “Soft dendritic microparticles with unusual adhesion and structuring properties,” Nat. Mater., vol.18, no.12, pp.1315–1320, Dec.2019, doi: 10.1038 / s41563- 019-0508-z. Smoukov, SK, et al. Scalable Liquid Shear-Driven Fabrication of Polymer Nanofibers. Advanced Materials 2015, 27 (16), 2642–2647. doi: 10.1002 / adma.201404616. Tamburini, D, et al, “The characterisation of shellac resin by flow injection and liquid chromatography coupled with electrospray ionisation and mass spectrometry,” Sci Rep, vol.7, no.1, p.14784, Nov.2017, doi: 10.1038 / s41598-017-14907-7. Velev, OD, et al, “Biodegradable biopolymer films,” US20220235188A1, Jul.28, 2022 Velev, OD, et al, “Fractal-like polymeric particles and their use in diverse applications,” US20240076509A1, Mar.07, 2024. Zhan, K, et al., “Impact of thermomechanical reprocessing on multilayer plastic packaging blend,” Polymer Degradation and Stability, vol. 222, p. 110710, Apr. 2024, doi: 10.1016 / j.polymdegradstab.2024.110710.

Claims

ATTORNEY DOCKET NO.221407-2160 CLAIMS What is claimed is:

1. A composite film comprising one or more layers comprising a first biodegradable polymer in contact with one or more layers comprising a second biodegradable polymer.

2. The composite film of claim 1, wherein the first biodegradable polymer comprises agarose, chitosan, sodium alginate, polycaprolactone (PCL), polylactic acid (PLA), a derivative thereof, or any combination thereof.

3. The composite film of claim 1, wherein the first biodegradable polymer is agarose.

4. The composite film of claim 1, wherein the second biodegradable polymer comprises shellac.

5. The composite film of claim 1, wherein the one or more layers comprising the second biodegradable polymer is continuous and contacts an entire surface of the one or more layers comprising the first biodegradable polymer.

6. The composite film of claim 1, wherein the one or more layers comprising the second biodegradable polymer is discontinuous and contacts a portion comprising less than an entire surface of the one or more layers comprising the first biodegradable polymer.

7. The composite film of claim 1, further comprising one or more layers comprising a third biodegradable polymer.

8. The composite film of claim 7, wherein the third biodegradable polymer comprises agarose, chitosan, sodium alginate, polycaprolactone (PCL), polylactic acid (PLA), a derivative thereof, or any combination thereof.

9. The composite film of claim 7 or 8, wherein the third biodegradable polymer is different from the first biodegradable polymer.

10. The composite film of claim 7, wherein the third biodegradable polymer is chitosan.

11. The composite film of claim 1, wherein the one or more layers comprising the first biodegradable polymer, the second biodegradable polymer, or the third biodegradable polymer, if present, further comprises a plasticizer.

12. The composite film of claim 11, wherein the plasticizer is biodegradable.

13. The composite film of claim 11, wherein the plasticizer comprises glycerol, polyethylene glycol (PEG), or any combination thereof.

14. The composite film of claim 13, wherein the one or more layers comprising the first biodegradable polymer comprises glycerol.ATTORNEY DOCKET NO.221407-2160 15. The composite film of claim 13, wherein the first biodegradable polymer comprises agarose.

16. The composite film of claim 14, wherein the agarose and the glycerol are present in a ratio of from about 1:1 (w / w) to about 1:0.20 (w / w).

17. The composite film of claim 14, wherein the agarose and the glycerol are present in a ratio of about 1:1 (w / w).

18. The composite film of claim 1, wherein the second biodegradable polymer comprises shellac.

19. The composite film of claim 18, wherein the shellac does not comprise a plasticizer.

20. The composite film of claim 13, wherein the one or more layers comprising the second biodegradable polymer comprises PEG.

21. The composite film of claim 20, wherein the PEG comprises PEG200, PEG400, PEG4000, or any combination thereof.

22. The composite film of claim 20, wherein the shellac and the PEG are present in a ratio of from about 1:0.20 (w / w) to about 1:0.05 (w / w).

23. The composite film of claim 20, wherein the shellac and the PEG are present in a ratio of about 1:0.10 (w / w).

24. The composite film of claim 18, wherein the agarose and shellac are present in a ratio of from about 1:20 (w / w) to about 1:1 (w / w).

25. The composite film of claim 18, wherein the agarose and shellac are present in a ratio of about 1:5 (w / w).

26. The composite film of any one of claims 18-25, where at least one of the one or more layers is a thermoplastic layer.

27. The composite film of claim 26, wherein the thermoplastic layer comprises shellac.

28. The composite film of claim 26, wherein the thermoplastic layer is on an outward-facing surface of the film.

29. The composite film of claim 26, wherein the thermoplastic layer of the composite film is bonded to a thermoplastic layer of a second composite film.

30. The composite film of claim 1, wherein the composite film is flat.

31. The composite film of claim 1, wherein the composite film has been thermoformed to comprise a three-dimensional shape.ATTORNEY DOCKET NO.221407-2160 32. The composite film of claim 30, wherein the three-dimensional shape comprises a cube, cylinder, a tetrahedron, a pouch, or any combination thereof.

33. The composite film of claim 1, wherein the composite film is biodegradable.

34. The composite film of claim 1, wherein the composite film is optically translucent.

35. The composite film of claim 1, wherein the composite film has a transmittance of from about 65% to about 85% between about 380 nm and 700 nm.

36. The composite film of claim 1, comprising a plurality of layers comprising the first biodegradable polymer and a plurality of layers comprising the second biodegradable polymer, wherein individual members of the plurality of layers comprising the first biodegradable polymer alternate with individual members of the plurality of layers comprising the second biodegradable polymer.

37. The composite film of claim 1, comprising a layer comprising the first biodegradable polymer sandwiched between two individual layers comprising the second biodegradable polymer.

38. The composite film of claim 1, wherein the composite film has a water contact angle of from about 65° to about 100 °.

39. The composite film of claim 1, wherein the composite film has a tensile strength of from about 1 MPa to about 45 MPa.

40. The composite film of claim 1, wherein the composite film has an elongation at break of from about 5% to about 50%.

41. The composite film of claim 1, wherein the composite film develops from about a 10% to about a 100% increase in weight after 24 hours of immersion in water.

42. The composite film of claim 1, wherein the composite film develops less than a 50% increase in weight after 24 hours of immersion in water.

43. The composite film of claim 1, wherein the composite film has a low permeability to water, oxygen, bacteria, fungi, or any combination thereof.

44. The composite film of claim 1, wherein the composite film is substantially impermeable to water, oxygen, bacteria, fungi, or any combination thereof.

45. A consumer product package comprising the composite film of any one of claims 1-44.

46. The consumer product package of claim 45, wherein the package contains a food product, a pharmaceutical product, an agricultural product, a household product, an office product, a detergent pouch, a personal care product, wrapping for a pallet, or a protective cover.ATTORNEY DOCKET NO.221407-2160 47. The consumer product package of claim 45, wherein the consumer product package comprises a seal between two thermoplastic layers of the composite film.

48. The consumer product package of claim 47, wherein the seal is a heat seal.

49. A method for making a composite film, the method comprising: (a) forming a first biopolymer solution comprising a first biopolymer and a first solvent; (b) solution casting the first biopolymer solution to form a first biopolymer layer and drying the first biopolymer layer; (c) forming a second biopolymer solution comprising a second biopolymer and a second solvent; (d) applying the second biopolymer solution to at least one side of the first biopolymer layer to form a second biopolymer layer and drying the second biopolymer layer to form the composite film.

50. The method of claim 49, wherein the second biopolymer solution is applied using solution casting, bar coating, doctor blading, injection molding, shaped extrusion, or any combination thereof.

51. The method of claim 49, wherein the first biopolymer solution comprises from about 1% (w / v) to about 4% (w / v) of the first biopolymer.

52. The method of claim 49, wherein the second biopolymer solution comprises from about 5% (w / v) to about 50% (w / v) of the second biopolymer.

53. The method of claim 49, wherein the first biopolymer comprises agarose, chitosan, sodium alginate, polycaprolactone (PCL), polylactic acid (PLA), a derivative thereof, or any combination thereof.

54. The method of claim 53, wherein the first biopolymer is agarose.

55. The method of claim 49, wherein the first solvent comprises water.

56. The method of claim 49, wherein the second biopolymer comprises shellac.

57. The method of claim 49, wherein the second solvent comprises ethanol.

58. The method of claim 49, wherein the first biopolymer solution, the second biopolymer solution, or both the first biopolymer solution and the second biopolymer solution comprise a plasticizer.

59. The method of claim 58, wherein the plasticizer comprises glycerol, polyethylene glycol (PEG), or a combination thereof.ATTORNEY DOCKET NO.221407-2160 60. The method of claim 59, wherein the first biopolymer solution comprises glycerol.

61. The method of claim 59, wherein the agarose and glycerol are present in a ratio of from about 1:1 (w / w) to about 1:0.20 (w / w).

62. The method of claim 59, wherein the second biopolymer solution comprises PEG.

63. The method of claim 62, wherein the PEG comprises PEG200, PEG400, PEG4000, or any combination thereof.

64. The method of claim 62, wherein a ratio of the shellac and PEG is from about 1:0.20 (w / w) to about 1:0.05 (w / w).

65. The method of claim 49, further comprising repeating steps (a)-(d) one or more times to form a multilayered composite film.

66. The method of claim 65, wherein the multilayered composite film comprises alternating layers of the first biopolymer and the second biopolymer.

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