Methods of increasing the water resistance of a material and related compositions and articles

Abstract

Generally described herein are methods of forming and of increasing the water resistance of a chitosan-based material (e.g., in the form of a faux leather material), related compositions for forming such materials, and articles, textiles, and / or garments that may be made from the materials.

Description

[0001]METHODS OF INCREASING THE WATER RESISTANCE OF A MATERIAL AND RELATED COMPOSITIONS AND ARTICLES RELATED APPLICATIONS This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application No.63 / 689,608, filed August 30, 2024, and entitled “METHODS OF INCREASING THE WATER RESISTANCE OF A MATERIAL AND RELATED COMPOSITIONS AND ARTICLES,” which is incorporated herein by reference in its entirety for all purposes. TECHNICAL FIELD Generally described herein are methods of forming and of increasing the water resistance of a chitosan-based material (e.g., in the form of a faux leather material), related compositions for forming such materials, and articles, textiles, and / or garments that may be made from the materials. SUMMARY Methods of forming and of increasing the water resistance of a chitosan-based material (e.g., in the form of a faux leather material), related compositions for forming such materials, and articles, textiles, and / or garments that may be made from the materials are generally described. The subject matter of the present invention involves, in some cases, interrelated products, alternative solutions to a particular problem, and / or a plurality of different uses of one or more systems and / or articles. According to certain embodiments, a method of increasing water resistance of a material is described. In some embodiments, the method comprises: exposing the material to a solution comprising one or more sulfate salts and one or more alcohols, ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ at least partially crosslinking the chitosan with one or more sulfate anions of the one or more sulfate salts. In some embodiments, a material is described. In certain embodiments, the material comprises chitosan at least partially crosslinked with one or more sulfate anions, one or more plasticizers, one or more acids, one or more free sulfate salts, and one or more free salts of the one or more acids.#14338547v1 In certain embodiments, a method is described, the method comprising exposing a material comprising chitosan and one or more silver salts embedded within the material to visible light and / or ultraviolet (UV) light to reduce at least a portion of the one or more silver salts to silver metal. According to some embodiments, a silver-colored material is described. In certain embodiments, the material comprises chitosan, one or more plasticizers, one or more acids, and silver metal, wherein the silver metal is embedded within the material. Other advantages and novel features of the present invention will become apparent from the following detailed description of various non-limiting embodiments of the invention when considered in conjunction with the accompanying figures. In cases where the present specification and a document incorporated by reference include conflicting and / or inconsistent disclosure, the present specification shall control. BRIEF DESCRIPTION OF THE DRAWINGS Non-limiting embodiments of the present invention will be described by way of example with reference to the accompanying figures, which are schematic and are not intended to be drawn to scale. In the figures, each identical or nearly identical component illustrated is typically represented by a single numeral. For purposes of clarity, not every component is labeled in every figure, nor is every component of each embodiment of the invention shown where illustration is not necessary to allow those of ordinary skill in the art to understand the invention. In the figures: FIG.1 shows a schematic diagram of a chitosan-based material in the form of a layer, in accordance with certain embodiments. FIG.2 shows a schematic diagram of a textile material comprising the chitosan- based material layer of FIG.1 disposed on a backing layer, in accordance with certain embodiments. DETAILED DESCRIPTION Methods of forming and of increasing the water resistance of a chitosan-based material (e.g., in the form of a faux leather material), related compositions for forming such materials, and articles, textiles, and / or garments that may be made from the materials are generally described. In some embodiments, a method comprises exposing#14338547v1 a material comprising chitosan to a solution (e.g., a substantially non-aqueous solution) comprising one or more sulfate salts (e.g., dissolved in one or more alcohols) and at least partially crosslinking the chitosan with one or more sulfate anions of the one or more sulfate salts. The resulting material comprising chitosan at least partially crosslinked with the one or more sulfate anions has an increased water resistance as compared to a material that is otherwise equivalent but does not comprise the chitosan at least partially crosslinked with the one or more sulfate anions. According to certain embodiments, the solution may comprise one or more polyols (e.g., glycerol). In some embodiments, exposing the material to the solution comprising the one or more polyols plasticizes the material with the one or more polyols. Such methods may advantageously provide a substantially water-resistant and plasticized chitosan-based material via a combined ionic crosslinking and plasticization process. In some embodiments, methods of rendering such materials a silver color are described. In certain embodiments, for example, prior to exposing the material to the solution to increase the water resistance of the material (and optionally plasticize the material), the material may be treated as described herein to comprise one or more silver salts embedded within the material (e.g., embedded throughout a bulk of the material). In some embodiments, a method comprises exposing the silver salt-containing material to visible light and / or UV light to reduce (e.g., chemically reduce) at least a portion of the one or more silver salts to silver metal, thereby imparting the silver color. In certain embodiments, the resulting material comprises silver metal embedded within the material (e.g., embedded throughout a bulk of the material). Such methods may advantageously provide a silver-colored chitosan-based material via a photoreduction process. The silver-colored chitosan-based material may be further processed via the ionic crosslinking (and optional plasticization) process described herein to increase the water resistance of the material (and optionally plasticize the material). According to certain embodiments chitosan-based materials (e.g., in the form of a faux leather material) are described herein. In some embodiments, a material resulting from the ionic crosslinking (and optional plasticization) process comprises chitosan at least partially crosslinked with one or more sulfate anions, one or more plasticizers, one or more acids, one or more free sulfate salts, and one or more free salts of the one or more acids. In certain embodiments, a silver-colored material resulting from a#14338547v1 photoreduction process comprises chitosan, one or more plasticizers, one or more acids, and silver metal embedded within the material (e.g., embedded throughout a bulk of the material). According to some embodiments, a silver-colored material resulting from a photoreduction process and an ionic crosslinking (and an optional plasticization) process comprises chitosan at least partially crosslinked with one or more sulfate anions, one or more plasticizers, one or more acids, one or more free sulfate salts, one or more free salts of the one or more acids, and silver metal embedded within the material (e.g., embedded throughout a bulk of the material). In certain embodiments, the chitosan-based materials are suitable for any of a variety of applications as a substitute for animal hide leathers, such as components of clothing, clothing accessories, upholstery, luggage, sporting goods, and the like. According to certain embodiments, chitosan-based materials (e.g., films) are solution cast from chitosan polymer dissolved in an organic acid (e.g., lactic acid), as chitosan is selectively soluble in water only at a low pH. The chitosan-containing solution may contain additives such as reinforcing macrofibers, microfibers, and / or nanofibers (e.g., microfibrillated cellulose) to control mechanical properties, as well as pigments for coloration. In certain embodiments, after drying, the material is comprised of an organic acid salt of chitosan (e.g., chitosan lactate). Left as cast, the material can redissolve on contact with water. As such, the material may be post-treated to be water resistant (e.g., for use in fashion applications), in accordance with certain embodiments. Post-treatment to render the material water resistant is conventionally done by regenerating uncharged chitosan from the chitosan salt by washing the material in a basic solution, such as a NaOH bath, followed by a series of washout baths, or gentle acid baths, to neutralize residual base and return the material to a skin compatible pH. Regenerated native chitosan films, however, exhibit a high degree of hydrogen bonding between chains, and so are stiff and brittle, and require plasticization. Plasticizer cannot be included in the starting polymer solution, as the base bath will wash it out. Therefore, conventionally, the films are “replasticized” using a subsequent plasticizer:water bath. The conventional post-treatment process to render the film water resistant and plasticized has several issues. For example, as the base bath is aqueous, during regeneration the film exists in a “race condition” whereby the water of the bath is dissolving the film at the same time as the base dissolved in the water is regenerating an#14338547v1 insoluble material. This produces undesired swelling of the film, outside-in anisotropy, and in extreme cases, core-shell behavior and porosity. To mitigate this, strong base baths are used, generally >3M NaOH, which presents a significant safety hazard. Moreover, plasticization by replasticization results in qualitatively different interactions between plasticizer and polymer molecules. While plasticizer can be washed back into the film, and plasticize effectively, the plasticizer exists as “free” plasticizer, weakly bound to the backbone polymer, in a system where polymer-polymer and plasticizer-plasticizer interactions are relatively stronger than polymer-plasticizer interactions. This results in defects in high-humidity environments. Specifically, in high humidity, water from the air displaces weakly bound plasticizer in the material, resulting in a “weeping” effect as plasticizer migrates to the surface. In extreme cases, this presents as literal pools of plasticizer or crusty layers of solid plasticizer on the surface of the material. To address these issues, an alternative method of increasing the water resistance of a chitosan-based material is described herein that includes one-step ionic crosslinking of the dry solution-cast film in a non-aqueous bath. This allows for safer treatment and, in certain embodiments, inclusion of plasticizer in the original casting solution directly, enabled by the non-aqueous and slight anti-solvent nature of the bath, which slows loss of plasticizer while crosslinking occurs. According to certain embodiments, mixtures of divalent anions such as sulfate salts (e.g., ammonium and / or sodium sulfate), when dissolved in a non-aqueous solution comprising an ethanol:glycerol mixture, form an immiscible second phase with the glycerol partitioned from the ethanol. The glycerol content of the second phase may act as a solubilizing medium for the sulfate salts, while minimizing plasticization effects of using, e.g., a pure glycerol or other polyol bath. Pure alcohol or other less polar liquids do not work as efficiently due to the low salt content that can dissolve therein, their antisolvent behavior for the chitosan film, and slow kinetics due the viscosity of glycerol, which leads to overly long treatment times. According to some embodiments, plasticizers included in the original casting solution are more effective than those reintroduced by the conventional replasticization bath, indicating that such plasticizers exist in a qualitatively different “bound” state, in contrast to “free” washback plasticizer. As such, the plasticizer may be included at much#14338547v1 lower loading concentrations, sometimes <10% w / w chitosan, in contrast to replasticized films, which could exceed 30% plasticizer by final mass. The high plasticizing power, combined with the different interactions of the bound plasticizer, advantageously reduces weeping in high humidity. According to some embodiments, methods are provided for forming a chitosan- based material (e.g., as an intermediate and / or unprocessed material) prior to exposing the material to a solution to increase the water resistance of the material. In certain embodiments, the method comprises adding chitosan to water to provide an aqueous slurry comprising the chitosan. In some embodiments, the method further comprises adding one or more acids to the aqueous slurry comprising the chitosan to form an aqueous solution comprising the chitosan and the one or more acids. In certain embodiments, adding the one or more acids to the aqueous slurry facilitates dissolution of at least a portion of the chitosan. In certain embodiments, the aqueous solution comprises chitosan at least partially suspended in the solution and chitosan at least partially dissolved in the solution (e.g., the aqueous solution is a slurry and / or suspension). In some embodiments, the one or more acids are added to the aqueous slurry comprising the chitosan while mixing and / or stirring. The one or more acids may be any of a variety of suitable, preferably organic, acids. In certain embodiments, for example, the one or more acids comprise lactic acid, citric acid, formic acid, maleic acid, acetic acid, gluconic acid, and / or combinations thereof. Other acids are also possible. In certain embodiments, the aqueous slurry and / or the aqueous solution comprising the chitosan further comprises one or more plasticizers. As used herein, the term “plasticizer” refers to a substance able to produce and / or promote plasticity of a material, produce and / or promote flexibility of a material, and / or reduce brittleness of a material. In certain embodiments, one or more plasticizers are added to the water prior to adding the chitosan to the water. In other embodiments, one or more plasticizers are added to the aqueous slurry comprising the chitosan after adding the chitosan to the water. In yet other embodiments, one or more plasticizers are added to the aqueous solution comprising the chitosan and the one or more acids after adding the one or more acids to the aqueous slurry comprising the chitosan.#14338547v1 The one or more plasticizers may comprise any of a variety of plasticizers. In some embodiments, the one or more plasticizers comprise a polyol. Suitable polyols include, but are not limited to, glycerol, sorbitol, propylene glycol, ethylene glycol and / or homopolymers thereof (e.g., polyglycerol-10, polyethylene glycol 200, polyethylene glycol 400 and the like). Other plasticizers are also possible. According to certain embodiments, the aqueous slurry and / or the aqueous solution comprising the chitosan further comprises microfibrillated cellulose. In some embodiments, for example, microfibrillated cellulose is added to the water prior to adding the chitosan to the water. In other embodiments, microfibrillated cellulose is added to the aqueous slurry comprising the chitosan after adding the chitosan to the water. In yet other embodiments, microfibrillated cellulose is added to the aqueous solution comprising the chitosan and the one or more acids after adding the one or more acids to the aqueous slurry comprising the chitosan. In some embodiments, the aqueous slurry and / or the aqueous solution comprising the chitosan further comprises one or more plant oils. In some embodiments, for example, one or more plant oils are added to the water prior to adding the chitosan to the water. In other embodiments, one or more plant oils are added to the aqueous slurry comprising the chitosan after adding the chitosan to the water. In yet other embodiments, one or more plant oils are added to the aqueous solution comprising the chitosan and the one or more acids after adding the one or more acids to the aqueous slurry comprising the chitosan. In certain embodiments, the one or more plant oils may advantageously act as a degassing agent. The one or more plant oils may comprise any of a variety of suitable plant oils. In some embodiments, the one or more plant oils comprise safflower oil. Other plant oils are also possible. In certain embodiments, the aqueous slurry and / or the aqueous solution comprising the chitosan further comprises one or more pigments. In some embodiments, for example, one or more pigments are added to the water prior to adding the chitosan to the water. In other embodiments, one or more pigments are added to the aqueous slurry comprising the chitosan after adding the chitosan to the water. In yet other embodiments, one or more pigments are added to the aqueous solution comprising the#14338547v1 chitosan and the one or more acids after adding the one or more acids to the aqueous slurry comprising the chitosan. According to certain embodiments, the aqueous slurry and / or the aqueous solution comprising the chitosan further comprises one or more silver salts. In some embodiments, for example, one or more silver salts are added to the water prior to adding the chitosan to the water. In other embodiments, one or more silver salts are added to the aqueous slurry comprising the chitosan after adding the chitosan to the water. In yet other embodiments, one or more silver salts are added to the aqueous solution comprising the chitosan and the one or more acids after adding the one or more acids to the aqueous slurry comprising the chitosan. The one or more silver salts may comprise any of a variety of suitable silver salts. In some embodiments, for example, the one or more silver salts comprise silver nitrate, silver carbonate, and / or combinations thereof. Other silver salts are also possible. In certain embodiments, the method for forming a chitosan-based material comprises degassing the aqueous slurry and / or the aqueous solution (e.g., to remove bubbles). In certain embodiments, degassing the aqueous slurry and / or the aqueous solution comprises applying a vacuum to the aqueous slurry and / or the aqueous solution comprising chitosan. In some embodiments, the one or more plant oils, described elsewhere herein in greater detail, act as a degassing agent to prevent and / or reduce foaming during degassing. In some embodiments, the method for forming a chitosan-based material further comprises disposing the aqueous solution into a mold and / or on or over a stationary or moving support. In certain embodiments, the aqueous solution is disposed into a mold and / or on or over a stationary or moving support to provide a chitosan-based material having a desired shape (e.g., after drying the aqueous solution), such as a chitosan-based material in the form of a roll or a layer (e.g., a film and / or sheet). According to some embodiments, the method for forming a chitosan-based material further comprises drying the aqueous solution to form a solid material (e.g., an intermediate material). In certain embodiments, the aqueous solution is dried at a temperature greater than or equal to 40oC, greater than or equal to 60oC, greater than or equal to 80oC, greater than or equal to 100oC, greater than or equal to 120oC, or greater. In some embodiments, the aqueous solution is dried at a temperature less than or equal to#14338547v1 120oC, less than or equal to 100oC, less than or equal to 80oC, less than or equal 60oC, less than or equal to 40oC, or less. Combinations of the above recited ranges are possible (e.g., the aqueous solution is dried at a temperature greater than or equal to 40oC and less than or equal to 120oC). Other ranges are also possible. In certain embodiments, the chitosan-based material (e.g., an intermediate material) is in the form of a textile material, a faux leather material, a leather-like material, or the like. In certain embodiments, after forming the material, the material may be further processed to color the material (e.g., render the material a silver color), increase the water resistance of the material, apply one or more backing layers, texturize and / or emboss the material, etc., as described elsewhere herein in greater detail. According to certain embodiments, the chitosan-based material (e.g., an intermediate material) comprises chitosan at least partially crosslinked with one or more organic ions of one or more organic acids. For example, in certain embodiments, the material comprises chitosan at least partially crosslinked with lactate, citrate, formate, maleate, acetate, gluconate, and / or combinations thereof. In some embodiments, the material comprises chitosan lactate, chitosan citrate, chitosan formate, chitosan maleate, chitosan acetate, chitosan gluconate, and / or combinations thereof. In some embodiments, the chitosan-based material (e.g., an intermediate material) comprises one or more acids. In some embodiments, for example, the material comprises lactic acid, citric acid, formic acid, maleic acid, acetic acid, gluconic acid, and / or combinations thereof. Other acids are also possible. In certain embodiments, at least a portion of the one or more acids used for forming the material remain embedded within the intermediate or final material. For example, in certain embodiments, the one or more acids are embedded throughout a bulk of the material. In certain embodiments, the one or more acids interact with one or more components of the material (e.g., chitosan). For example, in some embodiments, the one or more acids are bound (e.g., chemically bound) to one or more components of the material (e.g. chitosan). In certain embodiments, the chitosan-based material (e.g., an intermediate material) comprises one or more plasticizers. In some embodiments, for example, the material comprises a polyol plasticizer. Suitable polyols include, but are not limited to, glycerol, sorbitol, propylene glycol, ethylene glycol, and / or homopolymers thereof (e.g.,#14338547v1 polyglycerol-10, polyethylene glycol 200, polyethylene glycol 400, and the like). Other plasticizers are also possible. In some embodiments, the one or more plasticizers are embedded within the material. In certain embodiments, for example, the one or more plasticizers are embedded throughout a bulk of the material. In some embodiments, the one or more plasticizers interact with one or more components of the material (e.g., chitosan). In certain embodiments, for example, the one or more plasticizers are bound (e.g., chemically bound) to one or more components of the material (e.g., chitosan). According to some embodiments, the chitosan-based material (e.g., an intermediate material) comprises microfibrillated cellulose. In some embodiments, the microfibrillated cellulose is embedded within the material. In certain embodiments, for example, the microfibrillated cellulose is embedded throughout a bulk of the material. The microfibrillated cellulose may advantageously improve the mechanical properties of the material. According to some embodiments, the chitosan-based material (e.g., an intermediate material) comprises one or more pigments. In certain embodiments, the chitosan-based material (e.g., an intermediate material) may be made to have any of a variety of suitable forms. In some embodiments, the material is in the form of a roll. In other embodiments, the material is in the form of a layer (e.g., a film and / or sheet). The layer may have any of a variety of suitable thicknesses. For example, in some embodiments, the layer has a thickness greater than or equal to 1 micrometer, greater than or equal to 50 micrometers, greater than or equal to 100 micrometers, greater than or equal to 150 micrometers, greater than or equal to 200 micrometers, greater than or equal to 250 micrometers, or greater. In certain embodiments, the layer has a thickness less than or equal to 300 micrometers, less than or equal to 250 micrometers, less than or equal to 200 micrometers, less than or equal to 150 micrometers, less than or equal to 100 micrometers, less than or equal 50 micrometers, or less. Combinations of the above recited ranges are possible (e.g., the layer has a thickness greater than or equal to 1 micrometer and less than or equal to 300 micrometers, the layer has a thickness greater than or equal to 100 micrometers and less than or equal to 200 micrometers). Other ranges are also possible.#14338547v1 According to certain embodiments, the chitosan-based material (e.g., an intermediate material) is formed or processed to contain one or more silver salts. In certain embodiments, for example, the material comprises silver nitrate, silver carbonate, and / or combinations thereof. Other silver salts are also possible. In some embodiments, the one or more silver salts are embedded within the material. In some embodiments, for example, the one or more silver salts are embedded throughout a bulk of the material. The material may comprise chitosan and one or more silver salts in any of a variety of suitable mass ratios. In certain embodiments, for example, the material comprises a mass ratio of the chitosan to the one or more silver salts greater than or equal to 4:1, greater than or equal to 5:1, greater than or equal to 6:1, or greater than or equal to 7:1. In some embodiments, the material comprises a mass ratio of the chitosan to the one or more silver salts less than or equal to 8:1, less than or equal to 7:1, less than or equal to 6:1, or less than or equal to 5:1. Combinations of the above recited ranges are possible (e.g., the material comprises a mass ratio of the chitosan to the one or more silver salts greater than or equal to 4:1 and less than or equal to 8:1, the material comprises a mass ratio of the chitosan to the one or more silver salts greater than or equal to 5:1 and less than or equal to 7:1). Other ranges are also possible. According to some embodiments, a method of rendering a chitosan-based material (e.g., an intermediate material) a silver color is described. In some embodiments, the method comprises exposing a material comprising one or more silver salts embedded within the material (e.g., embedded throughout a bulk of the material) to visible light and / or ultraviolet (UV) light to reduce (e.g., chemically reduce) at least a portion of the one or more silver salts to silver metal. The term “UV light,” as used herein, refers to electromagnetic radiation having a wavelength from 100 nm to 379 nm. The term “visible light” is used herein to describe electromagnetic radiation having a wavelength from 380 nm to 750 nm. Suitable sources of visible light and / or UV light include, but are not limited to, the sun, light-emitting diodes (LEDs), and / or digital light processing projectors. In certain embodiments, after exposing the material comprising the one or more silver salts embedded within the material (e.g., embedded throughout a bulk of the material) to visible light and / or UV light, the material comprises silver metal embedded#14338547v1 within the material. In certain embodiments, for example, the material comprises silver metal embedded throughout a bulk of the material such that the material is silver-colored. According to some embodiments, the one or more silver salts may be reduced to silver metal via exposure to one or more reducing agents (e.g., hydroquinone and / or ascorbic acid). In some embodiments, after rendering the chitosan-based material a silver color, the material may be processed to increase the water resistance of the material, as described elsewhere herein in greater detail. According to certain embodiments, a method of increasing the water resistance of a chitosan-based material (e.g. an intermediate material) is described. In some embodiments, the method comprises exposing the chitosan-based material to a solution (e.g., by at least partially submerging the material in the solution or fully submerging the material in the solution). In certain embodiments, the solution is substantially non-aqueous. In certain embodiments, the solution comprises one or more sulfate salts. The solution may comprise the one or more sulfate salts in any of a variety of suitable amounts. In certain embodiments, for example, the solution comprises the one or more sulfate salts in an amount greater than or equal to 1 weight percent (wt%), greater than or equal to 2 wt%, greater than or equal to 3 wt%, or greater than or equal to 4 wt% versus a total weight of the solution. In some embodiments, the solution comprises the one or more sulfate salts in an amount less than or equal to weight 5 wt%, less than or equal to 4 wt%, less than or equal to 3 wt%, or less than or equal to 2 wt% versus a total weight of the solution. Combinations of the above recited ranges are possible (e.g., the solution comprises the one or more sulfate salts in an amount greater than or equal to 1 wt% and less than or equal to 5 wt% versus a total weight of the solution, the solution comprises the one or more sulfate salts in an amount greater than or equal to 2 wt% and less than or equal to 3 wt% versus a total weight of the solution). Other ranges are also possible. The solution may comprise any of a variety of suitable sulfate salts. For example, in some embodiments, the one or more sulfate salts comprise ammonium sulfate, sodium sulfate, and / or combinations thereof. Other sulfate salts are also possible.#14338547v1 According to certain embodiments, the solution may comprise one or more metal salts (e.g., zinc and / or iron salts). The solution may comprise the one or more metal salts in addition to, or in place or, the one or more sulfate salts. In some such embodiments wherein the solution comprises one or more metal salts, the chitosan of the chitosan- based material may be at least partially crosslinked with one or more metal cations of the one or more metal salts (e.g., via metal coordination crosslinking). In certain embodiments, the solution comprises one or more alcohols. In some embodiments, the solution comprises a mixture of alcohols (e.g., at least two alcohols, at least three alcohols, etc.). The solution may comprise the one or more alcohols in any of a variety of suitable amounts. In some embodiments, for example, the solution comprises the one or more alcohols in an amount greater than or equal to 5 wt.%, greater than or equal to10 wt.%, greater than or equal to 20 wt%, greater than or equal to 30 wt%, greater than or equal to 40 wt%, greater than or equal to 50 wt%, greater than or equal to 60 wt%, greater than or equal to 70 wt%, greater than or equal to 80 wt%, greater than or equal to 85 wt%, greater than or equal to 90 wt%, greater than or equal to 95 wt%, or greater, versus a total weight of the solution. In certain embodiments, the solution comprises the one or more alcohols in an amount less than or equal to 95 wt%, less than or equal to 90 wt%, less than or equal to 80 wt%, less than or equal to 70 wt%, less than or equal to 60 wt%, less than or equal to 50 wt%, less than or equal to 40 wt%, less than or equal to 30 wt%, less than or equal to 20 wt%, less than or equal to 10 wt%, less than or equal to 5 wt%, or less, versus a total weight of the solution. Combinations of the above recited ranges are possible (e.g., the solution comprises the one or more alcohols in an amount greater than or equal to 5 wt% and less than or equal to 95 wt% versus a total weight of the solution, the solution comprise the one or more alcohols in an amount greater than or equal to 60 wt% and less than or equal to 70 wt.% versus a total weight the solution). Other ranges are also possible. The solution may comprise any of a variety of suitable alcohols. For example, in certain embodiments, the solution comprises methanol, ethanol, propanol (e.g., isopropanol), and / or combinations thereof. Other alcohols are also possible. In some embodiments, the one or more alcohols comprise one or more polyols. According to some embodiments, the one or more polyols are configured to advantageously plasticize the material. For example, in some embodiments, the method#14338547v1 comprises plasticizing the chitosan-based material with the one or more polyols. As described elsewhere herein in greater detail, plasticization of the material may occur when forming the material (e.g., the intermediate material) due to the inclusion of one or more plasticizers in the aqueous solution comprising chitosan. In some embodiments, additional plasticization of the material occurs when exposing the material (e.g., the intermediate material) to the solution (e.g., the substantially non-aqueous solution) to increase the water resistance of the material due to the inclusion of one or more polyols in the solution. In other embodiments, plasticization of the material does not occur when forming the material (e.g., the intermediate material) and only occurs when exposing the material to the solution to increase the water resistance of the material via a combined ionic crosslinking and plasticization process. The solution may comprise the one or more polyols in any of a variety of suitable amounts. In some embodiments, for example, the solution comprises the one or more polyols in an amount greater than or equal to 10 wt%, greater than or equal to 20 wt%, greater than or equal to 30 wt%, or greater than or equal to 40 wt% versus a total weight of the solution. In certain embodiments, the solution comprises the one or more polyols in an amount less than or equal to 50 wt%, less than or equal to 40 wt%, less than or equal to 30 wt%, or less than or equal to 20 wt% versus a total weight of the solution. Combinations of the above recited ranges are possible (e.g., the solution comprises the one or more polyols in an amount greater than or equal to 10 wt% and less than or equal to 50 wt% versus a total weight of the solution, the solution comprises the one or more polyols in an amount greater than or equal to 20 wt% and less than or equal to 40 wt% versus a total weight of the solution). Other ranges are also possible. The solution may comprise any of variety of suitable polyols. In certain embodiments, for example, the solution comprises glycerol, sorbitol, propylene glycol, ethylene glycol. Other polyols are also possible. In certain embodiments, the solution is in the form of a mixture. For example, in some embodiments, the solution comprises a first portion comprising at least a first portion of the one or more sulfate salts at least partially dissolved and / or at least partially suspended in a first portion of the one or more alcohols. In certain embodiments, the solution comprises a second portion comprising a least a second portion of the one or more sulfate salts at least partially dissolved and / or at least partially suspended in a#14338547v1 second portion of the one or more alcohols, wherein the second portion of the one or more alcohols comprises one or more polyols. According to some embodiments, the one or more sulfate salts may have an increased solubility in the one or more polyols as compared to, for example, the one or more alcohols comprising methanol, ethanol, propanol, and / or combinations thereof. In some such embodiments, the solution comprises a first portion comprising at least a first portion of the one or more sulfate salts at least partially dissolved and / or at least partially suspended in a first portion of the one or more alcohols and a second portion comprising a least a second portion of the one or more sulfate salts at least partially dissolved and / or at least partially suspended in a second portion of the one or more alcohols, wherein the second portion of the one or more alcohols comprises the one or more polyols, and wherein the second portion of the one or more sulfate salts is greater than the first portion of the one or more sulfate salts. In certain embodiments, the solution is in the form of a biphasic mixture. For example, in some embodiments, the solution comprises a first phase comprising at least a first portion of the one or more sulfate salts at least partially dissolved and / or at least partially suspended in a first portion of the one or more alcohols. In certain embodiments, the solution comprises a second phase comprising a least a second portion of the one or more sulfate salts at least partially dissolved and / or at least partially suspended in a second portion of the one or more alcohols, wherein the second portion of the one or more alcohols comprises one or more polyols. According to some embodiments, the one or more sulfate salts may have an increased solubility in the one or more polyols as compared to, for example, the one or more alcohols comprising methanol, ethanol, propanol, and / or combinations thereof. In some such embodiments, the solution comprises a first phase comprising at least a first portion of the one or more sulfate salts at least partially dissolved and / or at least partially suspended in a first portion of the one or more alcohols and a second phase comprising a least a second portion of the one or more sulfate salts at least partially dissolved and / or at least partially suspended in a second portion of the one or more alcohols, wherein the second portion of the one or more alcohols comprises the one or more polyols, and wherein the second portion of the one or more sulfate salts is greater than the first portion of the one or more sulfate salts.#14338547v1 The solution may comprise the first portion of the one or more alcohols, the one or more sulfate salts, and the second portion of the one or more alcohols (e.g., the one or more polyols) in any of a variety of suitable mass ratios. In certain embodiments, for example, the solution comprises a mass ratio of the first portion of the one or more alcohols to the one or more sulfate salts and the second portion of the one more alcohols (e.g., the one or more polyols) greater than or equal to 1:1 or greater than or equal to 2:1. In some embodiments, the solution comprises a mass ratio of the first portion of the one or more alcohols to the one or more sulfate salts and the second portion of the one or more alcohols (e.g., the one or more polyols) less than or equal to 3:1 or less than or equal to 2:1. Combinations of the above recited ranges are possible (e.g., the solution comprises a mass ratio of the first portion of the one or more alcohols to the one or more sulfate salts and the second portion of the one or more alcohols greater than or equal to 1:1 and less than or equal to 3:1). In some embodiments, the solution is substantially non-aqueous. In other embodiments, the solution comprises water. The solution may comprise water in any of a variety of suitable amounts. In certain embodiments, for example, the solution comprises water in an amount less than or equal to 15 wt%, less than or equal to 10 wt%, less than or equal to 5 wt%, less than or equal to 4 wt%, less than or equal to 3 wt%, less than or equal to 2 wt%, or less than or equal to 1 wt% versus a total weight of the solution. In some embodiments, the solution comprises water in an amount greater than or equal to 0.1 wt%, greater than or equal to 1 wt%, greater than or equal to 2 wt%, greater than or equal to 3 wt%, greater than or equal to 4 wt%, greater than or equal to 5 wt%, or greater than or equal to 10 wt% versus a total weight of the solution. Combinations of the above recited ranges are possible (e.g., the solution comprises water in an amount less than or equal to 15 wt% and greater than or equal to 0.1 wt% versus a total weight of the solution, the solution comprises water in an amount less than or equal to 3 wt% and greater than or equal to 2 wt% versus a total weight of the solution). Other ranges are also possible. In certain embodiments, the solution comprises water in an amount less than or equal to 15 wt%, less than or equal to 10 wt%, less than or equal to 5 wt%, less than or equal to 4 wt%, less than or equal to 3 wt%, less than or equal to 2 wt%, or less than or equal to 1 wt% versus a total weight of the second portion of the one or more alcohols#14338547v1 (e.g., the one or more polyols). In some embodiments, the solution comprises water in an amount greater than or equal to 0.1 wt%, greater than or equal to 1 wt%, greater than or equal to 2 wt%, greater than or equal to 3 wt%, greater than or equal to 4 wt%, greater than or equal to 5 wt%, or greater than or equal to 10 wt% versus a total weight of the second portion of the one or more alcohols (e.g., the one or more polyols). Combinations of the above recited ranges are possible (e.g., the solution comprises water in an amount less than or equal to 15 wt% and greater than or equal to 0.1 wt% versus a total weight of the second portion of the one or more alcohols, the solution comprises water in an amount less than or equal to 3 wt% and greater than or equal to 2 wt% versus a total weight of the second portion of the one or more alcohols). Other ranges are also possible. According to some embodiments, the solution comprises one or more organic solvents (e.g., in addition to the one or more alcohols). In certain embodiments, for example, the solution comprises a ketone. Suitable ketones include, but are not limited to, methyl isobutyl ketone. In some embodiments, the solution comprises ethyl acetate. Other organic solvents are also possible. In certain embodiments, the method comprises at least partially crosslinking the chitosan with one or more sulfate anions of the one or more sulfate salts. In certain embodiments, at least partially crosslinking the chitosan with the one or more sulfate anions of the one or more sulfate salts comprises agitating the material (e.g., solid material) in the solution (e.g., by mixing and / or stirring the solution while the material is at least partially submerged in the solution). According to some embodiments, at least partially crosslinking the chitosan with the one or more sulfate anions of the one or more sulfate salts advantageously results in the material having an increased water resistance as compared to a material that is otherwise equivalent but does not include chitosan at least partially crosslinked with the one or more sulfate anions. According to some embodiments, the method comprises reusing the solution for one or more processing steps, e.g., to increase the water resistance of additional chitosan- based materials. In certain embodiments, the method may comprise one or more post-water resistance enhancing processing steps. In some embodiments, for example, the method#14338547v1 further comprises removing the material from the solution and drying the material (e.g., using heat). In certain embodiments, the method further comprises pressing the material. In some embodiments, pressing the material advantageously removes residual warping and / or wrinkling. In certain embodiments, the method further comprises embossing the material. In certain embodiments, embossing the material imparts a texture on the material. In some embodiments, the method further comprises applying a backing layer to the material. Any of a variety of suitable backing layers may be utilized, including, but not limited to, fabrics (e.g., knits, twills, and / or wovens). In certain embodiments, applying the backing layer comprises any of a variety of glue lamination and / or wet lamination processes known in the textile arts. In some embodiments, for example, a resin (e.g., raw pine rosin, a glycerol ester, etc.) is dissolved in an organic solvent (e.g., acetone) and applied to a surface of the material. In certain embodiments, the backing layer is then applied to the mixture disposed on the surface of the material (e.g., using a roller). In certain embodiments, a final chitosan-based material resulting from methods described herein is silver-colored resulting from the silver processing methods described elsewhere herein in greater detail. In some embodiments, the final chitosan-based material is substantially water resistant resulting from the water resistance increasing processing methods described elsewhere herein in greater detail. In certain embodiments, the chitosan-based material is processed to be in the form of a textile material, a faux leather material, a leather-like material, or the like. In some embodiments, the chitosan of the material is at least partially crosslinked with one or more sulfate anions. As described herein, the chitosan at least partially crosslinked with the one or more sulfate anions advantageously increases the water resistance of the material. In certain embodiments, the chitosan of the material is at least partially crosslinked with one or more organic ions of one or more organic acids. For example, in certain embodiments, the material comprises chitosan at least partially crosslinked with lactate, citrate, formate, maleate, acetate, gluconate, and / or combinations thereof. In some embodiments, the material comprises chitosan lactate, chitosan citrate, chitosan#14338547v1 formate, chitosan maleate, chitosan acetate, chitosan gluconate, and / or combinations thereof. The material (e.g., a processed material) may comprise chitosan (e.g., chitosan at least partially crosslinked with one or more sulfate anions, chitosan at least partially crosslinked with one or more organic ions of one or more organic acids) in any of a variety of suitable amounts. In certain embodiments, the material comprises chitosan in an amount greater than or equal to 20 wt%, greater than or equal to 30 wt%, greater than or equal to 40 wt%, greater than or equal to 50 wt%, greater than or equal to 60 wt%, or greater, versus a total weight of the material. In some embodiments, the material comprises chitosan in an amount less than or equal to 60 wt%, less than or equal to 50 wt%, less than or equal to 40 wt%, less than or equal to 30 wt%, less than or equal to 20 wt%, or less, versus a total weight of the material. Combinations of the above recited ranges are possible (e.g., the material comprises chitosan in an amount greater than or equal to 20 wt% and less than or equal to 60 wt% versus a total weight of the material, the material comprises chitosan in an amount greater than or equal to 30 wt% and less than or equal to 50 wt% versus a total weight of the material). Other ranges are also possible. According to some embodiments, the material (e.g., a processed material) comprises one or more acids. Suitable acids are described elsewhere herein in greater detail, including, but not limited to, lactic acid, citric acid, formic acid, maleic acid, acetic acid, gluconic acid, and / or combinations thereof. Other acids are also possible. In certain embodiments, the one or more acids are embedded within the material. For example, in certain embodiments, the one or more acids are embedded throughout a bulk of the material. In certain embodiments, the one or more acids interact with one or more components of the material (e.g., chitosan). For example, in some embodiments, the one or more acids are bound (e.g., chemically bound) to one or more components of the material (e.g., chitosan). The material (e.g., a processed material) may comprise one or more acids in any of a variety of suitable amounts. In certain embodiments, the material comprises one or more acids in an amount greater than or equal to 10 wt%, greater than or equal to 15 wt%, greater than or equal to 20 wt%, greater than or equal to 25 wt%, greater than or equal to 30 wt%, or greater, versus a total weight of the material. In some embodiments,#14338547v1 the material comprises one or more acids in an amount less than or equal to 30 wt%, less than or equal to 25 wt%, less than or equal to 20 wt%, less than or equal to 15 wt%, less than or equal to 10 wt%, or less, versus a total weight of the material. Combinations of the above recited ranges are possible (e.g., the material comprises one or more acids in an amount greater than or equal to 10 wt% and less than or equal to 30 wt% versus a total weight of the material, the material comprises one or more acids in an amount greater than or equal to 15 wt% and less than or equal to 25 wt% versus a total weight of the material). Other ranges are also possible. In certain embodiments, the material (e.g., a processed material) comprises one or more plasticizers. Suitable plasticizers are described elsewhere herein in greater detail, including, but not limited to, polyols such as glycerol, sorbitol, propylene glycol, ethylene glycol, and / or homopolymers thereof (e.g., polyglycerol-10, polyethylene glycol 200, polyethylene glycol 300, and the like). Other plasticizers are also possible. In some embodiments, the one or more plasticizers are embedded within the material. For example, in certain embodiments, the one or more plasticizers are embedded throughout a bulk of the material. In some embodiments, the one or more plasticizers interact with one or more components of the material (e.g., chitosan). In certain embodiments, for example, the one or more plasticizers are bound (e.g., chemically bound) to one or more components of the material (e.g., chitosan). The material (e.g., a processed material) may comprise one or more plasticizers in any of a variety of suitable amounts. In certain embodiments, the material comprises one or more plasticizers in an amount greater than or equal to 10 wt%, greater than or equal to 15 wt%, greater than or equal to 20 wt%, greater than or equal to 25 wt%, greater than or equal to 30 wt%, or greater, versus a total weight of the material. In some embodiments, the material comprises one or more plasticizers in an amount less than or equal to 30 wt%, less than or equal to 25 wt%, less than or equal to 20 wt%, less than or equal to 15 wt%, less than or equal to 10 wt%, or less, versus a total weight of the material. Combinations of the above recited ranges are possible (e.g., the material comprises one or more plasticizers in an amount greater than or equal to 10 wt% and less than or equal to 30 wt% versus a total weight of the material, the material comprises one or more plasticizers in an amount greater than or equal to 15 wt% and less than or equal to 25 wt% versus a total weight of the material). Other ranges are also possible.#14338547v1 In certain embodiments, the material (e.g., a processed material) comprises one or more free sulfate salts. Suitable free sulfate salts include, but are not limited to, ammonium sulfate, sodium sulfate, and / or combinations thereof. Other free sulfate salts are also possible. In some embodiments, the one or more free sulfate salts are embedded within the material. In certain embodiments, for example, the one or more sulfate salts are embedded throughout a bulk of the material. The material (e.g., a processed material) may comprise one or more free sulfate salts in any of a variety of suitable amounts. In certain embodiments, the material comprises one or more free sulfate salts in an amount greater than or equal to 1 wt%, greater than or equal to 2 wt%, greater than or equal to 5 wt%, or greater, versus a total weight of the material. In some embodiments, the material comprises one or more free sulfate salts in an amount less than or equal to 5 wt%, less than or equal to 2 wt%, less than or equal to 1 wt%, or less, versus a total weight of the material. Combinations of the above recited ranges are possible (e.g., the material comprises one or more free sulfate salts in an amount greater than or equal to 1 wt% and less than or equal to 5 wt% versus a total weight of the material). Other ranges are also possible. According to certain embodiments, the material (e.g., a processed material) comprises one or more free salts of the one or more acids. Suitable free salts of the one or more acids include, but are not limited to, ammonium lactate, ammonium citrate, ammonium formate, ammonium maleate, ammonium acetate, ammonium gluconate, sodium lactate, sodium citrate, sodium formate, sodium maleate, sodium acetate, sodium gluconate, and / or combinations thereof. Other free salts of the one or more acids are also possible. In some embodiments, the one or more free salts of the one or more acids are embedded within the material. For example, in some embodiments, the one or more free salts of the one or more acids are embedded throughout a bulk of the material. The material (e.g., a processed material) may comprise one or more free salts of the one or more acids in any of a variety of suitable amounts. In certain embodiments, the material comprises comprise one or more free salts of the one or more acids in an amount greater than or equal to 1 wt%, greater than or equal to 2 wt%, greater than or equal to 5 wt%, or greater, versus a total weight of the material. In some embodiments, the material comprises one or more free salts of the one or more acids in an amount less than or equal to 5 wt%, less than or equal to 2 wt%, less than or equal to 1 wt%, or less,#14338547v1 versus a total weight of the material. Combinations of the above recited ranges are possible (e.g., the material comprises one or more free salts of the one or more acids in an amount greater than or equal to 1 wt% and less than or equal to 5 wt% versus a total weight of the material). Other ranges are also possible. According to some embodiments, the material (e.g., a processed material) comprises microfibrillated cellulose. In some embodiments, the microfibrillated cellulose is embedded within the material. In certain embodiments, for example, the microfibrillated cellulose is embedded throughout a bulk of the material. The microfibrillated cellulose may advantageously improve the mechanical properties of the material. The material (e.g., a processed material) may comprise microfibrillated cellulose in any of a variety of suitable amounts. In certain embodiments, the material comprises microfibrillated cellulose in an amount greater than or equal to 1 wt%, greater than or equal to 2 wt%, greater than or equal to 5 wt%, or greater, versus a total weight of the material. In some embodiments, the material comprises microfibrillated cellulose in an amount less than or equal to 5 wt%, less than or equal to 2 wt%, less than or equal to 1 wt%, or less, versus a total weight of the material. Combinations of the above recited ranges are possible (e.g., the material comprises microfibrillated cellulose in an amount greater than or equal to 1 wt% and less than or equal to 5 wt% versus a total weight of the material). Other ranges are also possible. According to some embodiments, the material (e.g., a processed material) comprises one or more pigments. According to some embodiments, the material (e.g., a processed material) is silver-colored. In some embodiments, for example, the material comprises silver metal. In certain embodiments, the silver metal is embedded within the material. In some embodiments, for example, the silver metal is embedded throughout a bulk of the material. According to certain embodiments, the water resistance of the material may be measured via a water droplet test according to ISO 105-E07 (textiles) and / or ISO 15700 (leather). Briefly, a water droplet is exposed to a surface of the material, the water droplet is either wiped off or allowed to evaporate, and the material is evaluated for changes due to the water droplet exposure. In certain embodiments, the material is#14338547v1 substantially unchanged after wiping off the water droplet or allowing the water droplet to evaporate. In certain embodiments, the material (e.g., a processed material) may have any of a variety of suitable forms. In some embodiments, the material is in the form of a roll. In other embodiments, the material is in the form of a layer (e.g., a film and / or sheet). FIG.1 shows a schematic diagram of chitosan-based material 102 in the form of a layer, in accordance with certain embodiments. The layer may have any of a variety of suitable thicknesses. For example, in some embodiments, the layer has a thickness greater than or equal to 1 micrometer, greater than or equal to 50 micrometers, greater than or equal to 100 micrometers, greater than or equal to 150 micrometers, greater than or equal to 200 micrometers, greater than or equal to 250 micrometers, or greater. In certain embodiments, the layer has a thickness less than or equal to 300 micrometers, less than or equal to 250 micrometers, less than or equal to 200 micrometers, less than or equal to 150 micrometers, less than or equal to 100 micrometers, less than or equal 50 micrometers, or less. Combinations of the above recited ranges are possible (e.g., the layer has a thickness greater than or equal to 1 micrometer and less than or equal to 300 micrometers, the layer has a thickness greater than or equal to 100 micrometers and less than or equal to 200 micrometers). Other ranges are also possible. According to some embodiments, an article is described. In certain embodiments, the article comprises a material (e.g., a processed material, as described herein in greater detail) disposed on a backing layer. FIG.2 shows a schematic diagram of article 104 (e.g., a textile material) comprising chitosan-based material 102 in the form of a layer disposed on backing layer 106, in accordance with certain embodiments. The compositions and articles described herein may be used in any of a variety of suitable applications. In certain embodiments for example, a chitosan-based material (e.g., chitosan-based material 102 shown in FIG. 1) or an article (e.g., article 104 shown in FIG.2) is a component of an article, textile, and / or garment. In some embodiments, a material (e.g., chitosan-based material 102 shown in FIG.1) or an article (e.g., article 104 shown in FIG.2) is a component of clothing and / or a clothing accessory. Suitable articles of clothing and / or clothing accessories include, but are not limited to, shirts, sweaters, pants, shorts, jackets, footwear, hats, gloves, bags, belts, watch bands, and the#14338547v1 like. In some embodiments, a material (e.g., material 102 shown in FIG.1) or an article (e.g., article 104 shown in FIG.2) is a component of upholstery, luggage, sporting goods, and the like. Other applications are also possible. U.S. Patent Application No.18 / 107,780, filed February 9, 2023, patented as U.S. Patent No.11,732,405 on August 22, 2023, and entitled “Faux-Lether Biomaterial,” describes various faux leather biomaterials and processes for producing such materials and is incorporated herein by reference in its entirety for all purposes. International Patent Application No. PCT / US2023 / 013636, filed February 22, 2023, and entitled “Imitation Leather,” describes various leather-like materials composed of chitosan and bulk reinforcement agents such as microfibrillated cellulose, and is incorporated herein by reference in its entirety for all purposes. EXAMPLE 1 The following example describes the fabrication of materials comprising a chitosan film. First, 30 g of chitosan and 42 g of a 3% microfibrillated cellulose (MFC) slurry were added to 1410 g of water and mixed with both low and high shear. Then, 50 g of 88% lactic acid was added while stirring, which dissolved the chitosan and transformed the mixture, previously a slurry, into a polymer solution. Pigment could be added at this stage, as well as 3.75 g of a low viscosity plant oil, typically safflower oil, which serves as a degassing aide. This mixture was then subjected to vacuum to remove bubbles. The solution was poured into trays and dried overnight under hot moving air at 40-90oC in a large commercial food dehydrator. Higher temperatures resulted in skinning and / or ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^oC for 9 hours. The molds could be textured at this stage to impart a pattern. EXAMPLE 2 The following example describes the fabrication of materials comprising a chitosan rolled sheet. First, 30 g of chitosan and 42 g of a 3% MFC slurry were added to 250 g of water plus any pigment. This mixture was vacuum degassed and mixed to homogenization by low or a combination of low and high shear mixers. Then, while still under vacuum, 50#14338547v1 g of 88% lactic acid was added with a vacuum addition funnel under mixing. The mixture thickened significantly to a viscosity as high as 50k cPs. The solution was coated at ~1 mm wet thickness onto a flexible poly roll support web using a knife-over-roll setup, which then continuously passed through a 20 ft tunnel dryer at ~110oC at 1 / 2 m / minute line speed for a final dryness of ~30% residual moisture and final thickness of ~150 micrometers. EXAMPLE 3 The following example describes the fabrication of water-resistant chitosan-based materials. A bath of ammonium sulfate, glycerol, and alcohol (typically commercial grade denatured alcohol at 80% ethanol, 10% 2-propanol, 5% methanol, and 5% hexone) was prepared at ratios of 8 g of sulfate : 100 g of glycerol + 216 g of alcohol (i.e., 2:1 alcohol : glycerol salt mixture m / m). This bath was prepared by first dissolving the sulfate in a minimal amount of water, then mixing this solution with glycerol, then heating the mixture at ~110^C until most of the water was driven off (<~3% remainder). The resulting salt saturated glycerol was mixed with the alcohol, which formed two phases, one clear, one a milky presumed coacervate or salt colloid. In some instances, the step of driving off residual water was skipped, resulting in a final water content in the bath of ~10%. The sheets (described in Example 1) or slitted rolls (described in Example 2) were immersed in the liquid and agitated in a large tank overnight. Agitation mixed the two phases, though each phase on its own could result in waterproofed films. The minimal treatment time was about 10 hours. The bath: (i) crosslinked the material with divalent sulfate^^^^^) removed some, but not all the remaining acid^ and (iii) re-plasticized with glycerol. The alcohol served to slow and control these processes. It was observed that overtreating resulted in too much acid loss and too much glycerol replasticization, which could result in weeping in high humidity and / or stiffness of the material. A faster, more controlled (e.g. roll-2-roll) treatment in, e.g., saturated water solutions or solutions with lower alcohol content is also possible. After treatment, sheets were removed and allowed to dry. Sheets were typically stiff when removed, but soften as they reabsorb atmospheric moisture.#14338547v1 Sheets (or rolls) were then pressed and / or embossed. If a smooth / shiny finish was desired, sheets were pressed with mirror plates / calendared to remove any residual warping or wrinkling from mass loss or creasing in the baths. If a texture was desired, sheets were embossed (hot press) using standard leather embossing machinery. Finally, sheets were backed with standard fabrics like medium weight knits, twills, or wovens. Backing was accomplished using a wet lamination process. First, a layer of a tackier resin, typically raw pine rosin (though modified rosins like glycerol esters and hydrogenated products may also be used), was dissolved in acetone at 3:1 mass acetone:rosin. The acetone / rosin mixture was brushed on to serve as a tackier and water barrier. This layer was allowed to dry to the touch. Then, ammonia stabilized natural rubber latex was applied as a thick (~100-500 micrometer) layer using a roller, and the fabric was laid onto the wet latex, and smoothed / pressed into the adhesive layer. The layer and application occurred in such a manner that the latex soaked partially, but not fully, into the fabric and ensured a good bond but retained flexibility. The resulting sheets were comprised primarily of chitosan, partially crosslinked by sulfate, with glycerol plasticizer, residual acid, free ammonium sulfate and ammonium lactate, and residual water which was in equilibrium with the ambient water content of the air. EXAMPLE 4 The following example describes the fabrication of water-resistant chitosan-based materials that may be plasticized prior to water resistance enhancement processing. First, 4 g of sulfate salt was dissolved with heating in 100 g of glycerol. This mixture was then added to an alcohol mixture (85% ethanol, 10% isopropyl alcohol, 5% methanol, and 5% hexone) with a 1:2 mass ratio to dilute the mixture. Next, chitosan films, cast to a thickness of ~150 micrometers, were immersed in the above mixture for ~12 hours. Films were removed, wiped off, and the entrained alcohol was allowed to evaporate. The inclusion of a plasticizer, such as polyglycerol-10, in the original casting solution to form the chitosan film, at concentrations up to ~10% m / m chitosan, provided additional flex. The chitosan films were adhered to a backer using a glue lamination process. The films were 100% biobased and biodegradable.#14338547v1 EXAMPLE 5 The following example describes the fabrication of a material comprising a silver-colored chitosan film. Inclusion of photosensitive silver salts at casting time, followed by photo exposure, resulted in material sheets with a fine silver metallic finish, resembling a flexible mirror. The silver was embedded within the material itself, rather than just a surface layer or coating, which resulted in a subsurface scattering effect that warmed and deepened the metallic aesthetic relative to the metallic finish that is generally employed in the fabric finishing industry. The materials were also substantially conductive, and exhibited enhanced antimicrobial properties. Silver nitrate was dissolved in minimal water and mixed into the base solution at a ratio of 5 g of silver to 30 g of chitosan. Sheets were dried as described in Example 2. Dried sheets were exposed to visible light, typically by hanging in a window or other exposure to the sun, or by exposure to “black light” UV LED illumination. Conversion to a semi-metallic “tarnished” finish typically involved ~8 hours of exposure to 2 x 200 W or ~6 hours of south facing indoor sunlight. Conversion to a fully silvered “mirror” finish involved ~24 hours of UV exposure or 16 hours of daylight. Patterns have been imparted to the material at this stage by masking off areas of the film, and photography style exposure was used, e.g., a DLP projector with the UV filter removed. Keeping the material soluble in the high-water-activity film helped grow the photo reduced silver to large enough sizes to appear metallic. Chemical reduction of the silver without light exposure is also possible. Following exposure, the sheets were treated using the sulfate bath described in Example 3. This resulted in some washout of unreacted silver nitrate, which sharpened contrast. While several embodiments of the present invention have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and / or structures for performing the functions and / or obtaining the results and / or one or more of the advantages described herein, and each of such variations and / or modifications is deemed to be within the scope of the present invention. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials,#14338547v1 and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and / or configurations will depend upon the specific application or applications for which the teachings of the present invention is / are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, the invention may be practiced otherwise than as specifically described and claimed. The present invention is directed to each individual feature, system, article, material, and / or method described herein. In addition, any combination of two or more such features, systems, articles, materials, and / or methods, if such features, systems, articles, materials, and / or methods are not mutually inconsistent, is included within the scope of the present invention. The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.” The phrase “and / or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Other elements may optionally be present other than the elements specifically identified by the “and / or” clause, whether related or unrelated to those elements specifically identified unless clearly indicated to the contrary. Thus, as a non-limiting example, a reference to “A and / or B,” when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A without B (optionally including elements other than B); in another embodiment, to B without A (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc. As used herein in the specification and in the claims, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when separating items in a list, “or” or “and / or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of” or “exactly one of,” or, when used in the claims, “consisting of,” will refer to the#14338547v1 inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e. “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.” “Consisting essentially of,” when used in the claims, shall have its ordinary meaning as used in the field of patent law. As used herein in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and / or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc. In the claims, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of” and “consisting essentially of” shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.#14338547v1

Claims

CLAIMS What is claimed is:

1. A method of increasing water resistance of a material, comprising: exposing the material to a solution comprising one or more sulfate salts and one ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ at least partially crosslinking the chitosan with one or more sulfate anions of the one or more sulfate salts.

2. The method of claim 1, wherein the material is a faux leather material.

3. The method of any one of claims 1-2, wherein the one or more sulfate salts comprise ammonium sulfate, sodium sulfate, and / or combinations thereof.

4. The method of any one of claims 1-3, wherein the one or more alcohols comprise methanol, ethanol, propanol, and / or combinations thereof.

5. The method of any one of claims 1-4, wherein the one or more alcohols comprise one or more polyols.

6. The method of claim 5, wherein the one or more polyols comprise glycerol, sorbitol, propylene glycol, ethylene glycol, and / or combinations thereof.

7. The method of any one of claims 5-6, further comprising plasticizing the material with the one or more polyols.

8. The method of any one of claims 5-7, wherein the solution is in a form of a mixture, wherein a first portion of the mixture comprises at least a first portion of the one or more sulfate salts at least partially dissolved and / or at least partially suspended in a first portion of the one or more alcohols and a second portion of the mixture comprises a least a second portion of the one or more sulfate salts at least partially dissolved and / or at#14338547v1least partially suspended in a second portion of the one or more alcohols, wherein the second portion of the one or more alcohols comprises the one or more polyols.

9. The method of claim 8, wherein the solution comprises a mass ratio of the first portion of the one or more alcohols to the one or more sulfate salts and the one or more polyols greater than or equal to 1:1 and less than or equal to 3:

1.

10. The method of any one of claims 8-9, wherein the solution further comprises water.

11. The method of claim 10, wherein the solution comprises the water in an amount less than or equal to 15 weight percent (wt%) versus a total weight of the one or more polyols.

12. The method of any one of claims 1-11, further comprising, prior to the exposing step, steps of forming the material comprising the chitosan by: adding the chitosan to water to provide an aqueous slurry comprising the ^^^^^^^^^^^^^ adding one or more acids to the aqueous slurry to form an aqueous solution comprising the chitosan and the one or more acids.

13. The method of claim 12, wherein the aqueous slurry and / or the aqueous solution further comprise one or more plasticizers.

14. The method of any one of claims 12-13, wherein the aqueous slurry and / or the aqueous solution further comprise one or more silver salts.

15. The method of any one of claims 12-14, further comprising degassing the aqueous slurry and / or the aqueous solution.

16. The method of any one of claims 12-15, further comprising: ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^#14338547v1drying the aqueous solution to form the material.

17. The method of claim 16, wherein the material comprises chitosan at least partially crosslinked with one or more organic ions of the one or more acids.

18. The method of any one of claims 16-17, wherein the material comprises chitosan lactate, chitosan citrate, chitosan formate, chitosan maleate, chitosan acetate, chitosan gluconate, and / or combinations thereof.

19. The method of any one of claims 12-18, wherein the material further comprises the one or more acids.

20. The method of any one of claims 12-19, wherein the one or more acids comprise lactic acid, citric acid, formic acid, maleic acid, acetic acid, gluconic acid, and / or combinations thereof.

21. The method of any one of claims 13-20, wherein the material further comprises the one or more plasticizers.

22. The method of any one of claims 13-21, wherein the one or more plasticizers comprise glycerol, sorbitol, propylene glycol, ethylene glycol and / or homopolymers thereof.

23. The method of any one of claims 14-22, wherein the material further comprises the one or more silver salts embedded within the material.

24. The method of claim 23, wherein the one or more silver salts are embedded throughout a bulk of the material.

25. The method of any one of claims 14-24, wherein the one or more silver salts comprise silver nitrate, silver carbonate, and / or combinations thereof.#14338547v126. The method of any one of claims 14-25, further comprising: exposing the material to visible light and / or ultraviolet (UV) light to reduce at least a portion of the one or more silver salts to silver metal.

27. The method of any one of claims 1-26, wherein the material further comprises microfibrillated cellulose.

28. The method of any one of claims 1-27, wherein the material further comprises one or more plant oils.

29. The method of claim 28, wherein the one or more plant oils comprise safflower oil.

30. The method of any one of claims 1-29, further comprising, after the at least partially crosslinking step: pressing, embossing, and / or applying a backing layer to the material.

31. A material, comprising: chitosan at least partially crosslinked with one or ^^^^^^^^^^^^^^^^^^^^ one or more plasticizers^ ^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ one or more free salts of the one or more acids.

32. The material of claim 31, wherein the material is a faux leather material.

33. The material of any one of claims 31-32, further comprising chitosan at least partially crosslinked with one or more organic ions of the one or more acids.

34. The material of any one of claims 31-33, wherein further comprising chitosan lactate, chitosan citrate, chitosan formate, chitosan maleate, chitosan acetate, chitosan gluconate, and / or combinations thereof.#14338547v135. The material of any one of claims 31-34, wherein the one or more plasticizers comprise glycerol, sorbitol, propylene glycol, ethylene glycol, and / or homopolymers thereof.

36. The material of any one of claims 31-35, wherein the one or more acids comprise lactic acid, citric acid, formic acid, maleic acid, acetic acid, gluconic acid, and / or combinations thereof.

37. The material of any one of claims 31-36, wherein the one or more free sulfate salts comprise ammonium sulfate, sodium sulfate, and / or combinations thereof.

38. The material of any one of claims 31-37, wherein the one or more free salts of the one or more acids comprise ammonium lactate, ammonium citrate, ammonium formate, ammonium maleate, ammonium acetate, ammonium gluconate, sodium lactate, sodium citrate, sodium formate, sodium maleate, sodium acetate, sodium gluconate, and / or combinations thereof.

39. The material of any one of claims 31-38, further comprising microfibrillated cellulose.

40. The material of any one of claims 31-39, further comprising silver metal.

41. The material of claim 40, wherein the silver metal is embedded within the material.

42. The material of any one of claims 40-41, wherein the silver metal is embedded throughout a bulk of the material.

43. An article comprising the material of any one of claims 31-42, wherein the material is disposed on a backing layer.#14338547v144. The article of claim 43, wherein the article is a textile.

45. A method, comprising: exposing a material comprising chitosan and one or more silver salts embedded within the material to visible light and / or ultraviolet (UV) light to reduce at least a portion of the one or more silver salts to silver metal.

46. The method of claim 45, wherein the material is a faux leather material.

47. The method of any one of claims 45-46, wherein the one or more silver salts are embedded throughout a bulk of the material.

48. The method of any one of claims 45-47, wherein a mass ratio of the chitosan to the one or more silver salts is greater than or equal to 4:1 and less than or equal to 8:

1.

49. The method of any one of claims 45-48, wherein the one or more silver salts comprise silver nitrate, silver carbonate, and / or combinations thereof.

50. The method of any one of claims 45-49, further comprising, after the exposing step: exposing the material to a solution comprising one or more sulfate salts and one ^^^^^^^^^^^^^^^^^^^^^ at least partially crosslinking the chitosan with one or more sulfate anions of the one or more sulfate salts.

51. A silver-colored material, comprising: ^^^^^^^^^ one or more plasticizers^ ^^^^^^^^^^^^^^^^^^^^^^ silver metal, wherein the silver metal is embedded within the silver-colored material.#14338547v152. The silver-colored material of claim 51, wherein the silver-colored material is a faux leather material.

53. The silver-colored material of any one of claims 51-52, further comprising chitosan at least partially crosslinked with one or more organic ions of the one or more acids.

54. The silver-colored material of any one of claims 51-53, further comprising chitosan lactate, chitosan citrate, chitosan formate, chitosan maleate, chitosan acetate, chitosan gluconate, and / or combinations thereof.

55. The silver-colored material of any one of claims 51-54, wherein the chitosan is at least partially crosslinked with one or more sulfate anions.

56. The silver-colored material of any one of claims 51-55, wherein the one or more plasticizers comprise glycerol, sorbitol, propylene glycol, polyethylene glycol, and / or homopolymers thereof.

57. The silver-colored material of any one of claims 51-56, wherein the one or more acids comprise lactic acid, citric acid, formic acid, maleic acid, acetic acid, gluconic acid, and / or combinations thereof.

58. The silver-colored material of any one of claims 51-57, further comprising one or more free sulfate salts.

59. The silver-colored material of claim 58, wherein the one or more free sulfate salts comprise ammonium sulfate, sodium sulfate, and / or combinations thereof.

60. The silver-colored material of any one of claims 51-59, further comprising one or more free salts of the one or more acids.#14338547v161. The silver-colored material of claim 60, wherein the one or more free salts of the one or more acids comprise ammonium lactate, ammonium citrate, ammonium formate, ammonium maleate, ammonium acetate, ammonium gluconate, sodium lactate, sodium citrate, sodium formate, sodium maleate, sodium acetate, sodium gluconate, and / or combinations thereof.

62. The silver-colored material of any one of claims 51-61, further comprising microfibrillated cellulose.

63. The silver-colored material of any one of claims 51-62, wherein the silver metal is embedded throughout a bulk of the silver-colored material.

64. An article comprising the silver-colored material of any one of claims 51-63, wherein the silver-colored material is disposed on a backing layer.

65. The article of claim 64, wherein the article is a textile.#14338547v1

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