COMPOSITIONS, METHOD OF MANUFACTURING AN ARTICLE AND ARTICLES

Description

TECHNICAL FIELD

[0001] The present disclosure broadly relates to compositions, especially curable compositions, methods of making articles using the compositions, and articles produced thereby.BACKGROUND

[0002] Polyethylenimine (PEI) is commercially available in several forms such as linear, branched, and dendrimeric.

[0003] PEI is available in several forms such as linear, branched, and dendrimeric. Linear PEI can be represented by Formula I, below: wherein --- indicates continued linear polymeric ethylenimine-derived units or H. Linear PEI is available by post-modification of other polymers like poly(2-oxazolines) or N-substituted polyaziridines. Linear PEIs are commercially available and / or can be made according to known methods.

[0004] An exemplary branched PEI fragment can be represented by Formula II, below: wherein --- indicates continued linear and / or branched polymeric ethylenimine-derived units or H. As branching is typically more or less random, branched PEIs typically contain many compounds of this general type as a mixture. Branched PEI can be synthesized by the ring opening polymerization of aziridine. Branched PEIs are commercially available and / or can be made according to known methods.

[0005] Dendrimeric PEI is a special case of a branched PEI. An exemplary (generation 4) dendrimeric PEI is represented by Formula III, below: In this case, the PEI contains only primary and tertiary amino groups. Dendrimeric PEIs are commercially available and / or can be made according to known methods.

[0006] As used herein, the term "polyethylenimine" also includes protonated forms.

[0007] PEI can be covalently crosslinked (i.e., at least partially cured) by combining it with a polyfunctional (e.g., difunctional) crosslinking agent such as, for example, hexanediol diacrylate (HDDA). The HDDA reacts with a primary amino group by Michael addition at each acrylate group. However, reactions with such crosslinkers are typically too fast to permit their use in a one-part curable composition.

[0008] Patent application EP 2139812 discloses a flocculant composition, comprising a silicon-containing polymer flocculant for a desilication product and an anionic polymer flocculant for a Bayer process red mud, wherein the weight ratio of the amount of said silicon-containing polymer flocculant to the amount of said anionic polymeric flocculant in said flocculant composition is in the range of about 100: 1 to about 1 :10.

[0009] Patent application GB 2360523 discloses a process for treating a surface of a substrate with a composition comprising:-the reaction product of an amino-functional organic polymer, preferably a polyethylenimine and a reactive silane or a mixture of reactive silanes of the formula: (R3O)n(R4)3-n SiX in a non-aqueous solvent, by applying the composition on to the surface to form a layer and curing the layer in the presence of moisture.

[0010] Patent application JP2001049171 discloses a surface-coating composition comprising (A) a polyethyleneimine bearing no Si(OR1) group (R1 may be the same or different, and represents H, a lower alkyl group or an acyl group), (B) a compound bearing functional groups reactive with the amino group in the polyethyleneimine in the molecule, (C) an organic silane and / or the hydrolyzate thereof and (D) a solvent that can dissolve (A) polyethyleneimine, (B) the compound reactive with the compound A and (C) an organic silane and / or the hydrolyzate and condensate of the organic silane.

[0011] Patent application EP2366669 discloses hydrophobically modified Si-containing polyamines used for treating scale in industrial process streams. In particular, it discloses hydrophobically modified Si-containing polyamines used for treating aluminosilicate scale in difficult-to-treat industrial process streams, such as in the Bayer alumina process streams, nuclear waste streams and kraft paper mill effluent streams.

[0012] Patent application US2014370306 discloses an anti-bacterial and anti-fingerprint coating composition for forming a multi-functional coating layer having both anti-bacterial functions and anti-fingerprint functions on surfaces of touchscreens provided in portable terminals such as cellular phones, of panels or the like, provided in display devices such as liquid crystal displays (LCDs) or plasma display panels (PDPs), by a dry deposition method.

[0013] SONIA M. RIBEIRO ET AL, "Silica grafted polyethylenimine as heterogeneous catalyst for condensation reactions", APPLIED CATALYSIS A: GENERAL, AMSTERDAM, NL, (20110401), vol. 399, no. 1-2, pages 126 - 133, discloses Primary amine groups attached to a silica surface by using α,ω-diamines derivatives and (3-glycidyloxypropyl)-trimethoxysilane activation. The same activation is disclosed to be used to graft polyethylenimine, which also contains secondary and tertiary amine groups. These silica aminated structures are tested as heterogeneous catalysts in nitroaldol condensation with nitromethane, the derivative with the polyethylenimine moiety being the more active catalyst. This catalyst are also used in the Knoevenagel condensation of benzaldehydes with ethyl cyanoacetate under very mild reaction conditions.

[0014] It would be desirable to provide a reasonably stable one-part curable PEI-derived composition that can be applied to a substrate and cured.SUMMARY

[0015] The present invention is set out in the appended claims.

[0016] The present disclosure provides reasonably stable one-part curable PEI-derived compositions that can be applied to a substrate and cured to provide durable amine-functional coatings on the substrates. The coatings may be useful, for example, in chemical monitors (e.g., for monitoring exposure to an aldehydic disinfectant), and / or for modifying the hydrophilicity of and / or protecting a surface of a substrate. R represents an amine-reactive group containing 1 to 18 carbon atoms; Z represents a divalent organic group containing 1 to 8 carbon atoms; and each Y independently represents a hydrolyzable group.

[0017] In another aspect, the present disclosure provides a composition comprising compound preparable by reaction of components comprising a crosslinked polyethylenimine and at least one an amine-reactive hydrolyzable organosilane represented by the formula:         R-Z-SiY 3 wherein: R represents an amine-reactive group containing 1 to 18 carbon atoms; Z represents a divalent organic group containing 1 to 8 carbon atoms; and each Y independently represents a hydrolyzable group.

[0018] As used herein, the term "crosslinker" refers to a compound that forms multiple covalent bonds to a material (e.g., PEI) resulting in crosslinking.

[0019] As used herein, the terms "polymer" and "polymeric" refer to organic polymers only.

[0020] As used herein, the term "aqueous" means containing at least 5 weight percent of water (e.g., at least 10, 20, 30, 40, 50, 60, 70, 80, 90 weight percent of water, or even 100 percent of water).BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG. 1 is a schematic side view of an exemplary article 100 according to the present disclosure. The figure may not be drawn to scale.DETAILED DESCRIPTION

[0022] Compositions according to the present disclosure may comprise one or more compounds that are preparable, and optionally prepared, by reaction of components comprising an optionally crosslinked (e.g., using a crosslinker) polyethylenimine and at least one amine-reactive hydrolyzable organosilane.

[0023] Polyethylenimines include a large family of water-soluble polyamines of varying molecular weight. Polyethylenimines (PEIs) used in practice of the present disclosure may be linear, branched (e.g., randomly branched), or dendrimeric, as discussed hereinabove. Preferably, the PEIs are branched and contain a combination of primary and secondary amino nitrogen atoms.

[0024] It is generally known that the polymerization of ethylenimine (i.e., aziridine) itself does not result in a polymer that is completely composed of units having a linear structure, but that the degree of branching in polyethylenimine depends on the acid concentration and the temperature during polymerization. The degree of branching may, for example, vary between 12 and 38 percent. The formula of this type of branched polyethylenimine can be represented in the form of A, B, or C units, where A is an -R 5< -N(R 4< ) 2 unit, B is an R 4< -N(R 5< -) 2 unit, and C is an (-R 5< ) 3 N- unit, where R 4< is hydrogen and R 5< is an ethylene (-CH 2 CH 2 -) group. In some embodiments, the ratio of A to B to C units is from about 1:0.5:0.5 to about 1:2: 1, preferably from about 1:1:1 to about 1:2:1.

[0025] Polyethylenimines are widely available from commercial sources including, for example, BASF Corp. (Florham Park, New Jersey) under the trade designation "LUPASOL" polyethylenimine (e.g., LUPASOL FG, LUPASOL G 20, LUPASOL G 20 WF, LUPASOL G 35, and LUPASOL FT FP), and Sigma-Aldrich Corp. (St. Louis, Missouri).

[0026] The molecular weight of the PEI may be tailored depending on specific application requirements. In some embodiments, the PEI has a molecular weight (M W ) of 500 to 1500 g / mole. In some embodiments, the PEI has a molecular weight (M W ) of 1500 to 2000 g / mole. In some embodiments the PEI has a molecular weight (M W ) of 2000 to 5000 g / mole. In some embodiments the PEI has a molecular weight (M W ) of 5000 to 15000 g / mole. In some embodiments the PEI has a molecular weight (M W ) of 15000 to 30000 g / mole. In some embodiments the PEI has a molecular weight (M W ) of 30000 to 60000 g / mole. In some embodiments the PEI has a molecular weight (M W ) of 60000 to 100000 g / mole. In some embodiments the PEI has a molecular weight (M W ) of greater than or equal to 100000 g / mole.

[0027] In some embodiments, the polyethylenimine is crosslinked prior to, or simultaneous with, reaction with the amine-reactive hydrolyzable organosilane using a crosslinker. Suitable crosslinkers have a plurality (e.g., 2, 3, 4, or 5) of amine-reactive groups that form covalent bonds to the amino groups. Preferably, the crosslinker has two amine reactive groups. Typically, crosslinking is effected by simply combining the PEI and the crosslinker under relatively high dilution conditions (favoring intramolecular crosslinking) to minimize gelation caused by interchain crosslinking. Determination of appropriate conditions is within the capabilities of those skilled in the art.

[0028] Generally crosslinkers for PEIs include, for example, polyfunctional compounds such as: halohydrins (e.g., epichlorohydrin); alkylene dihalides (e.g., 1,4-dibromobutane, 1,2-diiodoethane); polyfunctional acrylates (e.g., 1,6-hexanediol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, ethoxylated trimethylolpropane triacrylates, trimethylolpropane triacrylate, glycerol triacrylate, dipentaerythritol hexaacrylate); diepoxides (e.g., aliphatic, cycloaliphatic and glycidyl ether diepoxides such as, for example, vinylcyclohexene dioxide, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl 3,4-epoxy-6-methylcyclohexanecarboxylate, bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate, dipentene dioxide, diglycidyl ether of bis-phenol A, diglycidyl ether of bis-phenol F, 1,4-butanediol diglycidyl ether); diesters (e.g., diethyl adipate, dimethyl fumarate, diethyl sebacate, and dimethyl maleate); divinylsulfone; polyfunctional acrylamides (e.g., piperazine diacrylamide, diacrylamide, N,N-methylene diacrylamide, and N,N'-(ethane-1,2-diyl) diacrylamide); polyisocyanates (e.g., hexamethylene diisocyanate, methylene diisocyanate), and polyaziridinyl compounds (e.g., tris-(1-aziridinyl)phosphine oxide), carbodiimides (e.g., 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide ), and N-hydroxysuccinimide.

[0029] Crosslinkers according to the invention are represented by the formula         R-Z-R wherein each of R and Z is independently as previously defined. Examples include diacrylates (e.g., 1,6-hexanediol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, and tetraethylene glycol diacrylate), triacrylates (e.g., ethoxylated trimethylolpropane triacrylates, trimethylolpropane triacrylate, and glycerol triacrylate), diepoxides (e.g., aliphatic, cycloaliphatic and glycidyl ether diepoxides such as, for example, vinylcyclohexene dioxide, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl 3,4-epoxy-6-methylcyclohexanecarboxylate, bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate, dipentene dioxide, diglycidyl ether of bis-phenol A, diglycidyl ether of bis-phenol F, 1,4-butanediol diglycidyl ether), diesters (e.g., diethyl adipate, dimethyl fumarate, diethyl sebacate, and dimethyl maleate), divinylsulfone, and diacrylamides (e.g., piperazine diacrylamide, diacrylamide, N,N-methylene diacrylamide, and N,N'-(ethane-1,2-diyl)diacrylamide).

[0030] Additional crosslinkers are known in the art, and will be available to those of skill in the art.

[0031] Preferably, an amount of the crosslinker is used that results in reaction with from 1 to 10 percent of the available primary nitrogen atoms in the PEI, more preferably 3 to 8 percent.

[0032] Amine-reactive hydrolyzable organosilane according to the invention are represented by the formula:         R-Z-SiY 3 wherein, R represents an amine-reactive group containing 1 to 18 carbon atoms. Preferably, R contains 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms, and even more preferably 1 to 3 carbon atoms. The amine-reactive groups R is selected from an isocyanato group (-N=C=O), an acryloxy group ( ),carboethoxy group a carbomethoxy group a vinylsulfonyl group ,and acrylamido groups (i.e., ). Z represents a divalent organic group containing 1 to 8 carbon atoms. In some embodiments, Z further contains from 1 to 6 heteroatoms selected from the group consisting of O, N, and S. Suitable divalent organic groups Z include, for example: hydrocarbylene groups having 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms, and even more preferably 1 to 3 carbon atoms; alkylenoxyalkylene having 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms; di(alkylene)amino groups having 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms; alkylenethiaalkylene groups having 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms. Specific examples of groups Z include methylene, ethylene, 1,2- and 1,3-propylene, butylene, isobutylene, hexylene, octylene, ethylcyclohexane-4,2'-diyl, ethylenoxyethylene, ethylenaminoethylene, ethylenoxypropylene, ethylenethiaethylene, and ethylene(methyl)aminoethylene. Of these, ethylene and 1,3-propylene are particularly preferred.

[0033] Each Y independently represents a hydrolyzable group. The term "hydrolyzable group', as used herein, denotes a group that can be hydrolyzed, which means it can react with water to provide silanol groups (Si-OH groups) that can further react with groups (e.g., hydroxyl groups) on the surface of the substrate. The hydrolysis and condensation reactions may occur spontaneously and / or in the presence of a hydrolysis / condensation catalyst. Examples of hydrolyzable groups include halide groups, such as chlorine, bromine, iodine or fluorine, alkoxy groups (-OR 1< wherein R 1< represents an alkyl group, preferably containing 1 to 6, more preferably 1 to 4 carbon atoms, and which may optionally be substituted by one or more halogen atoms), acyloxy groups (-O-(C=O)-R 2< wherein R 2< is as defined for R 1< ), aryloxy groups (-OR 3< wherein R 3< represents an aryl moiety, preferably containing 6 to 12, more preferably containing 6 to 10 carbon atoms, which may be optionally substituted by one or more substituents independently selected from halogens and C 1 -C 4 alkyl groups which may optionally be substituted by one or more halogen atoms). In the above formulas, R 1< , R 2< , and R 3< may include branched structures. In some preferred embodiments, each Y is independently selected from methoxy, ethoxy, hydroxy, acetoxy, chlorine, and bromine, of which methoxy and ethoxy are particularly preferred.

[0034] Specific examples of suitable amine-reactive hydrolyzable organosilanes include 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, 2-isocyanatoethyltriethoxysilane, 2-isocyanatoethyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 2-acryloxyethyltriethoxysilane, 2-acryloxyethyltrimethoxysilane 2-. Combinations of amine-reactive hydrolyzable organosilanes may be used.

[0035] Suitable amine-reactive hydrolyzable organosilanes may be purchased from commercial sources (e.g., as silane coupling agents, for example, from Gelest, Inc., Morrisville, Pennsylvania) and / or can be prepared by known methods. Preferably, the amine-reactive hydrolyzable organosilanes are reactive with primary amino groups, and optionally with secondary and / or tertiary amino groups. Preferably, he amine-reactive hydrolyzable organosilanes react more rapidly with primary amino groups than secondary and tertiary groups (if at all).

[0036] Typically, from 5 to 70 percent of the primary amino groups, preferably 10 to 40 percent of the primary amino groups in the PEI are reacted with the amine-reactive hydrolyzable silane, although this is not a requirement. In order to minimize leaching, preferably, at least 3 (e.g., at least 4, at least 5, or even at least 6 hydrolyzable silane groups are attached to each PEI polymer chain. The reaction is typically carried out in an organic solvent, although water may be present if desired. Upon coating and drying of the silane-functionalized PEI on a substrate, the hydrolyzable groups hydrolyze and form siloxane crosslinks to other silane groups. This results in a crosslinked PEI disposed on the substrate, and depending on the specific substrate, it may be chemically bonded to the substrate (e.g., if the substrate has available hydroxyl groups at its surface; e.g., as in the case of cellulosic paper). Exemplary substrates may include any substrate described herein.

[0037] The composition comprises an aqueous liquid vehicle, chosen to minimize reaction between them and other components of the composition. Examples of aqueous liquid vehicles include water and water-alcohol mixtures (e.g., water-isopropanol mixtures). The other ingredients are dissolved or dispersed in the liquid vehicle.

[0038] Any amount of the liquid vehicle can be used, and will typically depend on the particular composition and / or intended use.

[0039] The composition further comprises a polymeric binder. The polymeric binder is dispersible or soluble in the liquid vehicle. Exemplary polymeric binders include water-soluble polymers such as, for example, polyvinyl alcohol, hydroxyethyl cellulose, hydroxypropyl cellulose, and polymer latexes (e.g., polyurethane latexes, acrylic latexes, and vinyl acetate latexes). Suitable polymeric binders include film-forming polymeric binders, which may be provided, for example, as a latex. In some preferred embodiments, the latex is added to the composition prior to depositing the mixture on a substrate. Suitable film-forming polymers include acrylics (e.g., polybutyl acrylate and polymethyl methacrylate), ethylene-vinyl acetate copolymers (and partially or completely hydrolyzed versions thereof, polyvinyl alcohols, polyurethanes, polyamides, polyvinyl chloride, polystyrenes, polyesters, polycarbonates, natural and synthetic rubbers, and combinations thereof. The film-forming polymeric binder may be self-crosslinkable.

[0040] The composition may optionally further comprise various additives such as, for example, thickeners, fillers, fragrances, antioxidants, UV stabilizers, and surfactants.

[0041] Compositions according to the present disclosure can typically be prepared by simply mixing the various components in a vessel, optionally with heating or cooling.

[0042] Compositions according to the present disclosure are useful, for example, for method of making an article by coating at least a portion of a surface of a substrate with the composition, and then hydrolyzing at least some of the hydrolyzable groups to forms form covalent crosslinks (e.g., having Si-O-Si units) between PEI chains and / or the substrate. Hydrolysis may occur spontaneously on drying or standing. Optional heating may be advantageous in some instances.

[0043] Referring now to FIG. 1, exemplary article 100 comprises crosslinked layer 110 (i.e., a crosslinked reaction product of a composition according to the present disclosure) disposed on surface 120 of substrate 130. Crosslinked layer typically is hydrophilic, due to the presence of amino groups; however, this is not a requirement. Layer 110 may have any thickness. In some embodiments, the thickness of the crosslinked layer is less than 25.4 microns, preferably less than 5 microns.

[0044] Suitable substrates may be transparent or opaque. For example, the substrate may comprise glass, organic polymer, metal, ceramic, fabric, paper, and / or wood. Specific examples of suitable substrates include vehicles (e.g., buses, trucks, cars, rail cars, locomotives, vans, trolleys, motor homes, airplanes, bicycles, boats, and barges), mirrors, windows, lenses, visors, bridges, exterior architectural panels, showers, bathtubs, trailers, signs (e.g., traffic signs, advertising signs, neon signs), substrates with polymeric clearcoats, and outdoor furniture (e.g., plastic or metal chairs and tables). In another embodiment, the substrate may comprise a transparent film (e.g., polyethylene terephthalate, polymethyl methacrylate, or polycarbonate), membrane (e.g., nylon membranes or polyethersulfone membranes), or paper that is adapted for use as an indicator in an automated endoscope recycling apparatus.

[0045] The composition can be applied by a suitable method including, for example, spin coating, dip coating, spraying, brushing, roll coating, gravure coating, curtain coating, knife coating, and slot coating. In some embodiments, heating may be advantageously applied after coating (e.g., to facilitate crosslinking and / or remove any optional solvent).

[0046] Objects and advantages of this disclosure are further illustrated by the following non-limiting examples, but the particular materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit this disclosure.EXAMPLES

[0047] Unless otherwise noted, all parts, percentages, ratios, etc. in the Examples and the rest of the specification are by weight. TABLE OF REAGENTSBranched polyethylenimine (MW 60K g / mole, 50 wt. % in water)Thermo Fisher Scientific, Waltham, MassachusettsBranched polyethylenimine (MW 50-100K g / mole, 30 wt. % in water)Polysciences, Inc., Warrington, PennsylvaniaBranched polyethylenimine (MW 25K g / mole, cat# 408727)Sigma-Aldrich Corp., St. Louis, MissouriBranched polyethylenimine (MW 800 g / mole, cat# 408719)Sigma-Aldrich Corp.Polyethylenimine (80% ethoxylated, 37 wt. % in water, MW 50K)Sigma-Aldrich Corp.3-(Acryloxypropyl)trimethoxysilane (AS)Gelest, Inc., Morrisville, Pennsylvania3-Glycidoxypropyltrimethoxysilane (GPS)Gelest, Inc.PZ-28 polyfunctional aziridinePolyAziridine LLC., Medford, New JerseyDiethyl glutaconateSigma-Aldrich Corp.SR454 (3 mole ethoxylated trimethylolpropane triacrylate)Sartomer Corp., Exton, PennsylvaniaSR415 (20 mole ethoxylated trimethylolpropane triacrylate)Sartomer Corp.INCOREZ CS8057 polyurethane dispersionIncorez Ltd., Lancashire, EnglandNEOREZ R966 polyurethane dispersion (R966)DSM Corp., Elgin, IllinoisNEOCRYL A612 polyacrylic dispersion (A612)DSM Corp.POVAL 49-88 polyvinyl alcoholKuraray Ltd., SingaporePolyvinyl pyrrolidone K90, MW 360K g / moleSigma-Aldrich Corp.Nalco 1115 aqueous silica nanoparticle dispersion (spherical, 4 nm)Nalco Co., Naperville, Illinois3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilaneSigma-Aldrich Corp.IRGACURE 184 (1-hydroxy-cyclohexyl) phenyl ketoneBASF Corp., Florham Park, New Jerseyortho-phthalaldehyde (RAPICIDE OPA / 28)Medivators, Inc., Minneapolis, Minnesota EXAMPLE 1

[0048] Branched polyethylenimine (MW 25,000 g / mole, available from Sigma-Aldrich Corporation (cat # 408727) and diluted to a 3 wt. % aqueous solution, abbreviation of "bPEI") was mixed with a 3 wt. % aqueous solution of 3-(acryloxypropyl)trimethoxysilane (abbreviation of "AS", Gelest Inc.) in a ratio of 4:1 by weight bPEI:AS to form Solution A. NEOCRYL A612 (abbreviation of "A612", DSM Corporation) was diluted with distilled water to prepare a 3 wt. % solution (Solution B). Solutions A and B were then mixed together in a ratio of 2:3 by weight Solution A: Solution B to form the final coating formulation. A sample of filter paper (Whatman 410) was dip coated with the coating formulation and then dried at 80 °C for 3 minutes. The dried sample was cut into test strips (20 mm by 40 mm). The coated surface of the test strips was white in color.

[0049] Individual testing solutions of ortho-phthalaldehyde (OPA) in water were prepared at concentrations of 0.10 wt. %, and 0.35 wt. % OPA. The test strips were evaluated by immersing a test strip into a bath of the OPA testing solution for 5 minutes with the bath temperature maintained at 25 °C. The test strip was removed from the bath and checked for a color change by visual examination. In addition, test strips were evaluated to determine if any indicator color from a test strip leached into the OPA bath. For this test a new test strip was immersed and maintained in a fresh OPA bath (0.35 wt. % at 25 °C) for 30 minutes. The bath contained the minimum amount of OPA to fully cover the test strip (typically 1-2 mL). The test strip was then removed from the bath and the bath liquid was checked for color change by visual examination (no leaching = colorless bath, leaching = change in bath color from colorless to either a pale yellow or yellow color). The results are reported in Table 1.EXAMPLE 2

[0050] The procedure of Example 1 was followed, except that Solutions A and B were mixed together in a ratio of 1:1 by weight Solution A: Solution B to form the final coating formulation. The results are reported in Table 1.EXAMPLE 3

[0051] The procedure of Example 1 was followed, except that Solutions A and B were mixed together in a ratio of 3:2 by weight Solution A: Solution B to form the final coating formulation. The results are reported in Table 1.EXAMPLE 4

[0052] Branched polyethylenimine (MW 25,000 g / mole, available from Sigma-Aldrich Corporation (cat # 408727) and diluted to a 3 wt. % aqueous solution) was mixed with a 3 wt. % aqueous solution of 3-(acryloxypropyl)trimethoxysilane (abbreviation of "AS", Gelest Inc.) in a ratio of 7:3 by weight bPEI:AS to form Solution C. A612 was diluted with distilled water to prepare a 3 wt. % solution (Solution D). Solutions C and D were then mixed together in a ratio of 1:9 by weight Solution C:Solution D to form the final coating formulation. A sample of filter paper (Whatman 410) was dip coated with the coating formulation and then dried at 80 °C for 3 minutes. The dried sample was cut into test strips (20 mm by 40 mm). The coated surface of the test strips was white in color. The test strips were evaluated for color change and color leaching according to the procedure described in Example 1. The results are reported in Table 1.EXAMPLE 5

[0053] The procedure of Example 4 was followed, except that Solutions C and D were mixed together in a ratio of 2:3 by weight Solution C:Solution D to form the final coating formulation. The results are reported in Table 1.EXAMPLE 6

[0054] The procedure of Example 4 was followed, except that Solutions C and D were mixed together in a ratio of 1:1 by weight Solution C: Solution D to form the final coating formulation. The results are reported in Table 1.EXAMPLE 7

[0055] The procedure of Example 4 was followed, except that Solutions C and D were mixed together in a ratio of 3:2 by weight Solution C:Solution D to form the final coating formulation. The results are reported in Table 1.EXAMPLE 8

[0056] Branched polyethylenimine (MW 25,000 g / mole, available from Sigma-Aldrich Corporation (cat # 408727) and diluted to a 3 wt. % aqueous solution) was mixed with a 3 wt. % aqueous solution of 3-(acryloxypropyl)trimethoxysilane in a ratio of 3:2 by weight bPEI:AS to form Solution E. A612 was diluted with distilled water to prepare a 3 wt. % solution (Solution F). Solutions E and F were then mixed together in a ratio of 2:3 by weight Solution E:Solution F to form the final coating formulation. A sample of filter paper (Whatman 410) was dip coated with the coating formulation and then dried at 80 °C for 3 minutes. The dried sample was cut into test strips (20 mm by 40 mm). The coated surface of the test strips was white in color. The test strips were evaluated for color change and color leaching according to the procedure described in Example 1. The results are reported in Table 1.EXAMPLE 9

[0057] The procedure of Example 8 was followed, except that Solutions E and F were mixed together in a ratio of 1:1 by weight Solution E: Solution F to form the final coating formulation. The results are reported in Table 1.EXAMPLE 10

[0058] The procedure of Example 8 was followed, except that Solutions E and F were mixed together in a ratio of 3:2 by weight Solution E:Solution F to form the final coating formulation. The results are reported in Table 1.EXAMPLE 11

[0059] Branched polyethylenimine (MW 25,000 g / mole, available from Sigma-Aldrich Corporation (cat # 408727) and diluted to a 3 wt. % aqueous solution) was mixed with a 3 wt. % aqueous solution of 3-(acryloxypropyl)trimethoxysilane in a ratio of 1:1 by weight bPEI:AS to form Solution G. A612 was diluted with distilled water to prepare a 3 wt. % solution (Solution H). Solutions G and H were then mixed together in a ratio of 1:9 by weight Solution G: Solution H to form the final coating formulation. A sample of filter paper (Whatman 410) was dip coated with the coating formulation and then dried at 80 °C for 3 minutes. The dried sample was cut into test strips (20 mm by 40mm). The coated surface of the test strips was white in color. The test strips were evaluated for color change and color leaching according to the procedure described in Example 1. The results are reported in Table 1.EXAMPLE 12

[0060] Branched polyethylenimine (MW 25,000 g / mole, available from Sigma-Aldrich Corporation (cat # 408727) and diluted to a 3 wt. % aqueous solution) was mixed with a 3 wt. % aqueous solution of SR454 mutifunctional acrylate (ethoxylated trimethylolpropane triacrylate, Sartomer Corporation, Exton, PA) in a ratio of 4:1 by weight bPEI: SR454 to form the coating formulation. A sample of filter paper (Whatman 410) was dip coated with the coating formulation and then dried at 80 °C for 3 minutes. The dried sample was cut into test strips (20 mm by 40 mm). The coated surface of the test strips was white in color. The test strips were evaluated for color change and color leaching according to the procedure described in Example 1. The results are reported in Table 1, below TABLE 1Test Strip ofTest Strip Color after Immersion in 0.1 wt. % OPATest Strip Color after Immersion in 0.35 wt. % OPA BathColor from Test Strip Leached into 0.35 wt. % OPA BathExample 1pale yellowyellownoExample 2pale yellowyellownoExample 3pale yellowyellownoExample 4not testedpale yellownoExample 5pale yellowyellownoExample 6pale yellowyellownoExample 7pale yellowyellownoExample 8pale yellowyellownoExample 9pale yellowyellownoExample 10pale yellowyellownoExample 11not testedcolorlessnoExample 12pale yellowyellowno

[0061] For Examples 1-3 and 5-10 colorimetric analysis of the test strips following immersion in an OPA bath was conducted using an X-Rite SP64 colorimeter (X-Rite Inc.). The collected CIE L*a*b* color scale values (established by the International Commission on Illumination) are reported in Table 2, below. TABLE 2Test Strip ofColor Scale for Test Strip after Immersion in 0.1 wt. % OPAColor Scale for Test Strip after Immersion in 0.35 wt. % OPAL*a*b*L*a*b*Example 186.5-6.426.185.7-7.447.6Example 287.3-3.513.985.0-7.848.1Example 388.4-7.126.881.2-6.625.9Example 588.9-4.416.886.8-6.951.6Example 689.8-3.213.186.5-7.951.0Example 789.5-7.128.784.0-8.336.5Example 889.8-5.119.482.9-7.550.3Example 987.2-3.413.786.0-8.052.7Example 1083.2-7.231.387.3-9.143.3 EXAMPLE 13

[0062] Branched polyethylenimine (MW 25,000 g / mole, available from Sigma-Aldrich Corporation (cat # 408727) and diluted to a 3 wt. % aqueous solution) was mixed with a 3 wt. % aqueous solution of 3-(acryloxypropyl)trimethoxysilane (abbreviation of AS) in a ratio of 7:3 by weight bPEI:AS to form Solution I. NEOREZ R966 polyurethane dispersion (abbreviation of "R966", DSM Corporation) was diluted with distilled water to prepare a 3 wt. % solution (Solution J). Solutions I and J were then mixed together in a ratio of 1:9 by weight Solution I:Solution J to form the final coating formulation. A sample of filter paper (Whatman 410) was dip coated with the coating formulation and then dried at 80 °C for 3 minutes. The dried sample was cut into test strips (20 mm by 40 mm). The coated surface of the test strips was white in color.

[0063] A testing solution of ortho-phthalaldehyde (OPA) in water was prepared at a concentration of 0.35 wt. % OPA. The test strips were evaluated by immersing a test strip into a bath of the OPA testing solution for 5 minutes with the bath temperature maintained at 25 °C. The test strip was removed from the bath and checked for a color change by visual examination. Test strips were evaluated to determine if any indicator color from a test strip leached into the OPA bath using the procedure described in Example 1. The results are reported in Table 3.EXAMPLE 14

[0064] The procedure of Example 13 was followed, except that Solutions I and J were mixed together in a ratio of 3:7 by weight Solution I:Solution J to form the final coating formulation. The results are reported in Table 3.EXAMPLE 15

[0065] The procedure of Example 13 was followed, except that Solutions I and J were mixed together in a ratio of 1:1 by weight Solution I:Solution J to form the final coating formulation. The results are reported in Table 3.EXAMPLE 16

[0066] Branched polyethylenimine (MW 25,000 g / mole, available from Sigma-Aldrich Corporation (cat # 408727) and diluted to a 3 wt. % aqueous solution) was mixed with a 3 wt. % aqueous solution of 3-(acryloxypropyl)trimethoxysilane in a ratio of 1:1 by weight bPEI:AS to form Solution K. R966 polyurethane dispersion was diluted with distilled water to prepare a 3 wt. % solution (Solution L). Solutions K and L were then mixed together in a ratio of 1:9 by weight Solution K: Solution L to form the final coating formulation. A sample of filter paper (Whatman 410) was dip coated with the coating formulation and then dried at 80 °C for 3 minutes. The dried sample was cut into test strips (20 mm by 40 mm). The coated surface of the test strips was white in color. The test strips were evaluated for color change according to the procedure described in Example 1. Test strips were also evaluated to determine if any indicator color from a test strip leached into the OPA bath using the procedure described in Example 1. The results are reported in Table 3.EXAMPLE 17

[0067] The procedure of Example 16 was followed, except that Solutions K and L were mixed together in a ratio of 3:7 by weight Solution K:Solution L to form the final coating formulation. The results are reported in Table 3.EXAMPLE 18

[0068] The procedure of Example 16 was followed, except that Solutions K and L were mixed together in a ratio of 1:1 by weight Solution K:Solution L to form the final coating formulation. The results are reported in Table 3, below. TABLE 3Test Strip ofTest Strip Color after Immersion in 0.35 wt. % OPAColor from Test Strip Leached into 0.35 wt. % OPA BathExample 13pale yellownoExample 14yellownoExample 15bright yellownoExample 16pale yellownot testedExample 17yellownoExample 18bright yellowno EXAMPLE 19

[0069] Branched polyethylenimine (MW 25,000 g / mole, available from Sigma-Aldrich Corporation (cat # 408727) and diluted to a 2.5 wt. % aqueous solution) was mixed with a 2.5 wt. % aqueous solution of 3-(acryloxypropyl)trimethoxysilane in a ratio of 9:1 by weight bPEI:AS to form the final coating formulation. A sample of nylon 6,6 membrane (single reinforced layer nylon three zone membrane with nominal pore size of 1.8 microns, #080ZN, obtained from 3M Purification Inc., Meriden, Connecticut) was dip coated with the coating formulation and then dried at 80 °C for 3 minutes. The dried sample was cut into test strips (20 mm by 40 mm). The coated surface of the test strips was white in color.

[0070] Individual testing solutions of ortho-phthalaldehyde (OPA) in water were prepared at concentrations of 0.10 wt. %, and 0.35 wt. % OPA. The test strips were evaluated by immersing a test strip into a bath of the OPA testing solution for 5 minutes with the bath temperature maintained at 25 °C. The time point at which a color change of the test strip was first observed was recorded. Test strips were also evaluated to determine if any indicator color from a test strip leached into the OPA bath using the procedure described in Example 1. The results are reported in Table 4.EXAMPLE 20

[0071] The procedure of Example 19 was followed, except that the ratio of bPEI:AS in the final coating formulation was 4:1. The results are reported in Table 4.EXAMPLE 21

[0072] The procedure of Example 19 was followed, except that the ratio of bPEI:AS in the final coating formulation was 7:3. The results are reported in Table 4.EXAMPLE 22

[0073] The procedure of Example 19 was followed, except that the ratio of bPEI:AS in the final coating formulation was 3:2. The results are reported in Table 4.EXAMPLE 23

[0074] The procedure of Example 19 was followed, except that the ratio of bPEI:AS in the final coating formulation was 1:1. The results are reported in Table 4.EXAMPLE 24

[0075] The procedure of Example 19 was followed, except that the ratio of bPEI:AS in the final coating formulation was 2:3. The results are reported in Table 4, below. TABLE 4Test Strip of ExamplebPEI:ASTime to Color Change after Immersion in 0.1 wt. % OPA, secondsTime to Color Change after Immersion in 0.35 wt. % OPA, secondsColor from Test Strip Leached into 0.35 wt. % OPA Bath199:121067no204:126080no217:3253115no223:2no change at 300151no231:1no change at 300170no242:3no change at 300183no EXAMPLE 25

[0076] Branched polyethylenimine (MW 25,000 g / mole, available from Sigma-Aldrich Corporation (cat # 408727) and diluted to a 2.0 wt. % aqueous solution) was mixed with a 2.0 wt. % aqueous solution of 3-(acryloxypropyl)trimethoxysilane (abbreviation of "AS") in a ratio of 9:1 by weight bPEI:AS to form the final coating formulation. A sample of nylon membrane (described in Example 19) was dip coated with the coating formulation and then dried at 80 °C for 3 minutes. The dried sample was cut into test strips (20 mm by 40 mm). The coated surface of the test strips was white in color. The test strips were evaluated for time to color change according to the procedure described in Example 19. Test strips were also evaluated to determine if any indicator color from a test strip leached into the OPA bath using the procedure described in Example 1. The results are reported in Table 5.EXAMPLE 26

[0077] The procedure of Example 25 was followed, except that the ratio of bPEI:AS in the final coating formulation was 4:1. The results are reported in Table 5.EXAMPLE 27

[0078] The procedure of Example 25 was followed, except that the ratio of bPEI:AS in the final coating formulation was 7:3. The results are reported in Table 5.EXAMPLE 28

[0079] The procedure of Example 25 was followed, except that the ratio of bPEI:AS in the final coating formulation was 3:2. The results are reported in Table 5.EXAMPLE 29

[0080] The procedure of Example 25 was followed, except that the ratio of bPEI:AS in the final coating formulation was 1:1. The results are reported in Table 5.EXAMPLE 30

[0081] The procedure of Example 25 was followed, except that the ratio of bPEI:AS in the final coating formulation was 2:3. The results are reported in Table 5, below. TABLE 5Test Strip of ExamplebPEI:ASTime to Color Change after Immersion in 0.1 wt. % OPA, secondsTime to Color Change after Immersion in 0.35 wt. % OPA, secondsColor from Test Strip Leached into 0.35 wt. % OPA Bath259:124075no264:126087no277:3no change at 300120no283:2no change at 300160no291:1no change at 300180no302:3no change at 300210no EXAMPLE 31

[0082] Branched polyethylenimine (MW 25,000 g / mole, available from Sigma-Aldrich Corporation (cat # 408727) and diluted to a 2.5 wt. % aqueous solution) was mixed with a 2.5 wt. % aqueous solution of SR454 multifunctional acrylate in a ratio of 4:1 by weight bPEI: SR454 to form the coating formulation. A sample of nylon membrane (described in Example 19) was dip coated with the coating formulation and then dried at 80 °C for 3 minutes. The dried sample was cut into test strips (20 mm by 40 mm). The coated surface of the test strips was white in color. The test strips were evaluated for the time to color change according to the procedure described in Example 19. Test strips were also evaluated to determine if any indicator color from a test strip leached into the OPA bath using the procedure described in Example 1. The results are reported in Table 6.EXAMPLE 32

[0083] The procedure of Example 31 was followed, except that the ratio of bPEI: SR454 in the final coating formulation was 7:3. The results are reported in Table 6.EXAMPLE 33

[0084] The procedure of Example 31 was followed, except that the ratio of bPEI: SR454 in the final coating formulation was 3:2. The results are reported in Table 6.EXAMPLE 34

[0085] The procedure of Example 31 was followed, except that the ratio of bPEI: SR454 in the final coating formulation was 1: 1. The results are reported in Table 6.EXAMPLE 35

[0086] The procedure of Example 31 was followed, except that the ratio of bPEI: SR454 in the final coating formulation was 2:3. The results are reported in Table 6, below. TABLE 6Test Strip of ExamplebPEI:SR454Time to Color Change after Immersion in 0.1 wt. % OPA, secondsTime to Color Change after Immersion in 0.35 wt. % OPA, secondsColor from Test Strip Leached into 0.35 wt. % OPA Bath314:118040no327:321063no333:226086no341:1no change at 30097no352:3no change at 300145no EXAMPLE 36

[0087] Branched polyethylenimine (MW 800, available from Sigma-Aldrich Corporation (cat # 408719), abbreviation of "bPEI800") and diluted to a 2.5 wt. % aqueous solution) was mixed with a 2.5 wt. % aqueous solution of SR454 multifunctional acrylate in ratios of either 7:3, 1:1, or 2:3 by weight bPEI800:SR454 to form three separate coating formulations. Separate samples of nylon membrane (described in Example 19) were dip coated with one of the formulations and then dried at 80 °C for 3 minutes. The dried samples were cut into test strips (20 mm by 40 mm). The coated surface of the test strips was white in color. When the test strips were immersed into OPA baths according to the procedure described in Example 1 leaching of color into the test bath was observed for all of the test strips (visual examination). The greatest amount of color leaching was observed for the sample prepared with 9:1 ratio of bPEI800:SR454. The least amount of color leaching was observed for the sample with a 2:3 ratio of bPEI800:SR454.EXAMPLE 37

[0088] Branched polyethylenimine (MW 25,000 g / mole, available from Sigma-Aldrich Corporation (cat # 408727) and diluted to a 2.5 wt. % aqueous solution, abbreviation of "bPEI") was mixed with a 2.5 wt. % aqueous solution of SR454 mutifunctional acrylate in a ratio of 9:1 by weight bPEI: SR454 to form the coating formulation. A sample of nylon membrane (described in Example 19) was dip coated with the coating formulation and then dried at 80 °C for 3 minutes. The dried sample was cut into test strips (20 mm by 40 mm). The coated surface of the test strips was white in color.

[0089] A testing solution of ortho-phthalaldehyde (OPA) in water was prepared at a concentration of 0.35 wt. % OPA. The test strips were evaluated by immersing a test strip into a bath of the OPA testing solution for 5 minutes with the bath temperature maintained at 25 °C. The test strip was removed from the bath and checked for a color change from white to yellow. Test strips were also evaluated to determine if any indicator color from a test strip leached into the OPA bath using the procedure described in Example 1. The results are reported in Table 7.EXAMPLE 38

[0090] Branched polyethylenimine (MW 25,000 g / mole, available from Sigma-Aldrich Corporation (cat # 408727) and diluted to a 2.5 wt. % aqueous solution, abbreviation of "bPEI") was mixed with a 2.5 wt. % aqueous solution of SR454 multifunctional acrylate in a ratio of 9:1 by weight bPEI:SR454 to form Solution M. NEOCRYL A612 was diluted with distilled water to prepare a 2.5 wt. % solution (Solution N). Solutions M and N were then mixed together in a ratio of 1:1 by weight Solution M: Solution N to form the final coating formulation. A sample of nylon membrane (described in Example 19) was dip coated with the coating formulation and then dried at 80 °C for 3 minutes. The dried sample was cut into test strips (20 mm by 40 mm). The coated surface of the test strips was white in color. The test strips were evaluated by immersion in an OPA bath according to the procedure described in Example 37. The results are reported in Table 7.EXAMPLE 39

[0091] Branched polyethylenimine (MW 25,000 g / mole, available from Sigma-Aldrich Corporation (cat # 408727) and diluted to a 2.5 wt. % aqueous solution, abbreviation of "bPEI") was mixed with a 2.5 wt. % aqueous solution of SR454 multifunctional acrylate in a ratio of 9:1 by weight bPEI:SR454 to form Solution M. NEOREZ R966 polyurethane dispersion was diluted with distilled water to prepare a 2.5 wt. % solution (Solution O). Solutions M and O were then mixed together in a ratio of 1:1 by weight Solution M:Solution O to form the final coating formulation. A sample of nylon membrane (described in Example 19) was dip coated with the coating formulation and then dried at 80 °C for 3 minutes. The dried sample was cut into test strips (20 mm by 40 mm). The coated surface of the test strips was white in color. The test strips were evaluated by immersion in an OPA bath according to the procedure described in Example 37. The results are reported in Table 7.EXAMPLE 40

[0092] The procedure of Example 37 was followed, except that the ratio of bPEI:SR454 in the final coating formulation was 7:3. The results are reported in Table 7.EXAMPLE 41

[0093] Branched polyethylenimine (MW 25,000 g / mole, available from Sigma-Aldrich Corporation (cat # 408727) and diluted to a 2.5 wt. % aqueous solution, abbreviation of "bPEI") was mixed with a 2.5 wt. % aqueous solution of SR454 mutifunctional acrylate in a ratio of 7:3 by weight bPEI: SR454 to form Solution P. NEOCRYL A612 was diluted with distilled water to prepare a 2.5 wt. % solution (Solution Q). Solutions P and Q were then mixed together in a ratio of 1:1 by weight Solution P:Solution Q to form the final coating formulation. A sample of nylon membrane (described in Example 19) was dip coated with the coating formulation and then dried at 80 °C for 3 minutes. The dried sample was cut into test strips (20 mm by 40 mm). The coated surface of the test strips was white in color. The test strips were evaluated by immersion in an OPA bath according to the procedure described in Example 37. The results are reported in Table 7.EXAMPLE 42

[0094] Branched polyethylenimine (MW 25,000 g / mole, available from Sigma-Aldrich Corporation (cat # 408727) and diluted to a 3 wt. % aqueous solution, abbreviation of "bPEI") was mixed with a 2.5 wt. % aqueous solution of SR454 multifunctional acrylate in a ratio of 7:3 by weight bPEI:SR454 to form Solution P. NEOREZ R966 polyurethane dispersion was diluted with distilled water to prepare a 2.5 wt. % solution (Solution R). Solutions P and R were then mixed together in a ratio of 1:1 by weight Solution P:Solution R to form the final coating formulation. A sample of nylon membrane (described in Example 19) was dip coated with the coating formulation and then dried at 80 °C for 3 minutes. The dried sample was cut into test strips (20 mm by 40 mm). The coated surface of the test strips was white in color. The test strips were evaluated by immersion in an OPA bath according to the procedure described in Example 37. The results are reported in Table 7, below. TABLE 7Test Strip of ExampleColor of Test Strip after 5 min Immersion in 0.35 wt. % OPAColor from Test Strip Leached into 0.35 wt. % OPA Bath37yellowyes38yellowyes39yellowyes40bright yellowno41bright yellowno42bright yellowno Reference EXAMPLE 43

[0095] Branched polyethylenimine (MW 25,000 g / mole, available from Sigma-Aldrich Corporation (cat # 408727) and diluted to a 2.5 wt. % aqueous solution) was mixed with a 2.5 wt. % aqueous solution of crosslinker 3-glycidoxypropyl trimethoxysilane (abbreviation = "GPS", available from Gelest Inc.) in ratios of either 9:1, 4:1, or 7:3 by weight bPEI:crosslinker to form three separate coating formulations. Separate samples of nylon membrane (described in Example 19) were dip coated with one of the formulations and then dried at 80 °C for 3 minutes. The dried samples were cut into test strips (20 mm by 40 mm). The coated surface of the test strips was white in color. The test strips were immersed into OPA baths according to the procedure described in Example 19. The test strips were evaluated for time to color change according to the procedure described in Example 19. Test strips were also evaluated to determine if any indicator color from a test strip leached into the OPA bath using the procedure described in Example 1. The results are reported in Table 8. In addition, in a separate experiment the color of each strip was determined by visual inspection after being immersed in the OPA bath for 80 seconds and 300 seconds. At the 80 second time point, the test strips were a very pale yellow color. At the 300 second time point the test strips were a bright yellow color. TABLE 8Test Strip of Reference ExamplebPEI: crosslinkerTime to Color Change after Immersion in 0.1 wt. % OPA, secondsTime to Color Change after Immersion in 0.35 wt. % OPA, secondsColor from Test Strip Leached into 0.35 wt. % OPA Bath439:121067no434:126080no437:3293115no EXAMPLE 44

[0096] Branched polyethylenimine (MW 25,000 g / mole, available from Sigma-Aldrich Corporation (cat # 408727) and diluted to a 2.5 wt. % aqueous solution, abbreviation of "bPEI") was mixed with a 2.5 wt. % aqueous solution of 3-(acryloxypropyl)trimethoxysilane (abbreviation of "AS") in a ratio of 4:1 by weight bPEI:AS to form the final coating formulation. A sample of nylon membrane (described in Example 19) was dip coated with the coating formulation and then dried at 80 °C for 3 minutes. The dried sample was cut into test strips (20 mm by 40 mm). The coated surface of the test strips was white in color.

[0097] Individual testing solutions of ortho-phthalaldehyde (OPA) in water were prepared at concentrations of 0.10 wt. %, and 0.35 wt. % OPA. The test strips were evaluated by immersing a test strip into a bath prepared from the testing solution and maintained at either 10 °C, 20 °C, 25 °C, or 30 °C. The test strips were also immersed in the bath for varying periods of time (1.0, 1.35, 1.62, or 5 minutes). Prior to immersion in the OPA bath some of the test strips were immersed in a bath of 1% Intercept detergent (Medivators Inc.) for 7.5 minutes followed by immersion in a fresh distilled water bath for an additional 7.5 minutes and then air drying. Each test sample was removed from the OPA bath and the reflectance measurement of the test strip was determined at an emitted wavelength 450 nm using an X-Rite Handheld Spectrophotometer X-Rite eXact NGH Handheld Spectrophotometer with a 1.5 mm aperture (X-Rite Inc.). The mean reflectance values (n= 3) and corresponding test conditions are reported in Table 9, below. TABLE 9OPA Conc. In Bath, wt. %Bath Temp, °CImmersion Time, minutesPretreatment with DetergentReflectance, %0.35301.0yes410.35251.35yes470.35201.62yes570.35105yes550.35255yes300.35301.0no500.35251.35no470.35201.62no630.35105no680.35255no270.10255yes500.10255no55 Reference EXAMPLE 45

[0098] Branched polyethylenimine (MW 25,000 g / mole, available from Sigma-Aldrich Corporation (cat # 408727) and diluted to a 2.5 wt. % aqueous solution, abbreviation of "bPEI") was mixed with a 2.5 wt. % aqueous solution of NEOREZ R966 polyurethane dispersion in a weight ratio of 1:1 to form the coating formulation. A sample of nylon membrane (described in Example 19) was coated with a #24 Meyer rod (RD Specialties, Webster, New York) and then dried at 80 °C for 3 minutes. The dried sample was cut into test strips (20 mm by 40 mm). The coated surface of the test strips was white in color.

[0099] A testing solution of ortho-phthalaldehyde (OPA) in water was prepared at a concentration of 0.35 wt. % OPA. The test strips were evaluated by immersing a test strip into a bath of the OPA testing solution for either 1.35 or 5 minutes with the bath temperature maintained at 25 °C. Each test sample was removed from the bath and the reflectance measurement of the test strip was determined at an emitted wavelength 440 nm using an X-Rite Handheld Spectrophotometer X-Rite eXact NGH Handheld Spectrophotometer with a 1.5 mm aperture (X-Rite Inc.). The mean reflectance values (n= 3) and corresponding test conditions are reported in Table 10.EXAMPLE 46

[0100] Branched polyethylenimine (MW 25,000 g / mole, available from Sigma-Aldrich Corporation (cat # 408727) and diluted to a 2.5 wt. % aqueous solution, abbreviation of "bPEI") was mixed with a 2.5 wt. % aqueous solution of 3-(acryloxypropyl)trimethoxysilane (abbreviation of "AS") in a weight ratio of 7:3 to form the coating formulation. A sample of nylon membrane (described in Example 19) was coated with a #24 Meyer rod and then dried at 80 °C for 3 minutes. The dried sample was cut into test strips (20 mm by 40 mm). The coated surface of the test strips was white in color. The test strips were evaluated by immersion in an OPA bath according to the procedure described in Reference Example 45. The mean reflectance values (n= 3) and corresponding test conditions are reported in Table 10.EXAMPLE 47

[0101] Branched polyethylenimine (MW 25,000 g / mole, available from Sigma-Aldrich Corporation (cat # 408727) and diluted to a 2.5 wt. % aqueous solution, abbreviation of "bPEI") was mixed with a 2.5 wt. % aqueous solution of 3-(acryloxypropyl)trimethoxysilane (abbreviation of "AS") in a weight ratio of 7:3 to form Solution S. NEOREZ R966 polyurethane dispersion was diluted with distilled water to prepare a 2.5 wt. % solution (Solution T). Solutions S and T were then mixed together to form a final coating formulation with a weight ratio of 7:3:7 bPEI:AS:R966. A sample of nylon membrane (described in Example 19) was coated with a #24 Meyer rod and then dried at 80 °C for 3 minutes. The dried sample was cut into test strips (20 mm by 40 mm). The coated surface of the test strips was white in color. The test strips were evaluated by immersion in an OPA bath according to the procedure described in Reference Example 45. The mean reflectance values (n= 3) and corresponding test conditions are reported in Table 10, below. TABLE 10Test Strip of ExampleImmersion Time, minuteswt. % OPAReflectance, %451.350.35734550.3555461.350.35674650.3518471.350.35704750.3514 Reference EXAMPLE 48

[0102] Branched polyethylenimine (abbreviation of bPEI, MW 60,000 g / mole as a 50 wt. % solution in water) was mixed with a 30 wt. % polyurethane dispersion (#CS 8057, Incorez Copolymer Ltd., United Kingdom) and distilled water to form a coating formulation with a ratio of 1:3 by weight bPEI:polyurethane dispersion. The coating formulation (50 microliters) was applied as a circular dot to the surface of an injection molded chip (60 mm by 50 mm by 1 mm) of Bayblend T85 stock white (a polycarbonate (PC) and acrylonitrile butadiene styrene (ABS) blend; available from Bayer Material Science, Leverkusen, Germany). The chip with coated test dot was then dried at 100 °C for 15 minutes resulting in a clear coating over the white substrate.

[0103] Individual testing solutions of ortho-phthalaldehyde (OPA) in water were prepared at concentrations of 0.35 wt. % and 0.575 wt. % OPA. The coated chips were evaluated by immersing the coated portion of the chip into a bath prepared from the testing solution and maintained at 25 °C. The chips were immersed in the bath for either 1.35 minutes or 5 minutes. Each chip was removed from the bath and the coated dot was checked by visual inspection for a change in color from white to yellow. The results are reported in Table 11.Reference EXAMPLE 49

[0104] The procedure of Reference Example 48 was followed, except that the ratio of bPEI:polyurethane dispersion in the coating formulation was set at 1:1 by weight.Reference EXAMPLE 50

[0105] The procedure of Reference Example 48 was followed, except that the ratio of bPEI:polyurethane dispersion in the coating formulation was set at 3:1 by weight. Results are reported in Table 11, below. TABLE 11Reference ExamplebPEI: polyurethane dispersionColor of Test Dot following Immersion in Bath1.35 min in 0.35 wt. % OPA5 min in 0.35 wt. % OPA5 min in 0.575 wt. % OPA481:3very pale yellowpale yellowpale yellow491:1very pale yellowyellowyellow503:1very pale yellowbright yellowbright yellow Reference EXAMPLE 51

[0106] A testing solution of ortho-phthalaldehyde (OPA) in water was prepared at a concentration of 0.35 wt. % OPA. Test chips prepared according to Reference Example 51 were evaluated by immersing the coated portion of a test chip into a bath prepared from a testing solution with the bath temperature maintained at either 20 °C, 25 °C, or 30 °C. The test chips were immersed in the bath for varying periods of time (1.0, 1.35, 1.62, or 5 minutes). Each test chip was removed from the bath and reflectance of the test dot was determined at an emitted wavelength of 440 nm using an X-Rite Handheld Spectrophotometer X-Rite eXact NGH Handheld Spectrophotometer with a 1.5 mm aperture (X-Rite Inc.). The mean reflectance values (n=3) and the corresponding test conditions are reported in Table 12.Reference EXAMPLE 52

[0107] The same testing procedure as reported in Reference Example 51 was followed, except that prior to immersion in the OPA bath the coated chips were immersed in a bath of 1% Intercept detergent (Medivators, Inc.) for 7.5 minutes followed by immersion in a fresh distilled water bath for an additional 7.5 minutes and then air drying. Results are reported in Table 12, below. TABLE 12ExampleBath Temp, °CImmersion Time, minutesDetergent Used in methodReflectance, %52301.0yes2852251.35yes2052201.62yes2452255yes551301.0no3551251.35no2351201.62no2751255no13 Reference EXAMPLES 53-61

[0108] The coating formulations for Reference Examples 53-61 were prepared by pre-mixing branched polyethylenimine (bPEI, MW 60,000 g / mole as a 50 wt. % solution in water, available from Thermo Fisher Scientific, that was diluted to 10 wt. % in water) and R966 (10 wt. % in water). The crosslinkers 3-glycidoxypropyl trimethoxysilane (abbreviation = "GPS" and prepared as 10 wt. % in isopropyl alcohol) and PZ-28 (a polyfunctional aziridine available from PolyAziridine LLC., Medford, NJ and prepared as 10 wt. % in isopropyl alcohol) were added next with continued mixing to provide the specified coating formulations. The amount of each component (as 10 wt. % solutions) in a formulation is listed in Table 13. Each coating formulation was individually coated onto a separate clear PET polyester film substrate (5 mil) using a #24 Meyer rod. The coated films were dried at 85 °C for 5-10 minutes to form a clear coat. Test strips (about 25 mm by 102 mm) were prepared from the coated films. A bath of OPA (0.575 wt. % in water) was prepared and each test strip was evaluated by immersing the test strip in the bath for 300 seconds. The bath was maintained at 25 °C. The color of the test strip was determined by visual inspection after being immersed for 80 seconds and 300 seconds. The integrity of the test strip was determined by visually inspecting each test strip at 300 seconds for any signs of haze, cracking, blister formation, or swelling. In addition, test strips were evaluated to determine if any indicator color from a test strip leached into the OPA bath. For this test a new test strip was immersed and maintained in a fresh OPA bath (0.575 wt. % at 25 °C) for 30 minutes. The bath contained the minimum amount of OPA to fully cover the test strip (typically 1-2 mL). The test strip was then removed from the bath and the bath liquid was checked for color change by visual examination (no leaching = colorless bath, while leaching = change in bath color from colorless to either a pale yellow or yellow color). The results for color change (at 80 and 300 seconds), test strip integrity, and leaching are reported in Table 14. TABLE 13Reference ExamplebPEI, gR966, gGPS, gPZ-28, g535500.15545500.3555500.45564600.3573700.1558550.250.4559640.60.260730.70.1561820.80.1 TABLE 14 Reference ExampleColor after Immersion for 80 secColor after Immersion for 300 secTest Strip IntegrityColor from Test Strip Leached into 0.575 wt. % OPA Bath53clear to very pale yellowbright yellowno issueyes54clear to very pale yellowbright yellowno issueyes55clear to very pale yellowbright yellowno issueyes56pale yellowbright yellowno issueno57pale yellowbright yellowno issueno58pale yellowbright yellowno issueno59clear to very pale yellowbright yellowno issueno60clear to very pale yellowbright yellowno issueno61pale yellowbright yellowno issueno EXAMPLES 62-68

[0109] The coating formulations for Examples 62-68 were prepared by pre-mixing branched polyethylenimine (bPEI, MW 60,000 g / mole as a 50 wt. % solution in water, available from Thermo Fisher Scientific, that was diluted to 10 wt. % in water) and R966 (10 wt. % in water). The crosslinker GPS (neat liquid) or AS (neat liquid) was added next with continued mixing to form the specified coating formulations. The amount of each component in a formulation is listed in Table 15. Each coating formulation was individually coated onto a separate clear PET polyester film substrate (5 mil) using a #24 Meyer rod. The coated films were dried at 85 °C for 5-10 minutes to form a clear coat. Test strips (about 25 mm by 102 mm) were prepared from the coated films.

[0110] The test strips were evaluated for color change (at 80 and 300 seconds) and for integrity of the test strip according to the procedure described for Reference Example 53. The results are reported in Table 16. TABLE 15ExamplebPEI, gR966, gGPS, gAS, g62604000.66360400.6064703000.765802000.86680200.8067901000.96895500.95 TABLE 16 ExampleColor after Immersion for 80 secColor after Immersion for 300 secTest Strip Integrity62clear to very pale yellowbright yellowno issue63clear to very pale yellowbright yellowno issue64clear to very pale yellowbright yellowno issue65clear to very pale yellowbright yellowno issue66clear to very pale yellowbright yellowslight cracking67not determinednot determinedcracking68not determinednot determinedcracking EXAMPLE 69

[0111] Branched polyethylenimine (bPEI, MW 60,000 g / mole as a 50 wt. % solution in water, available from Thermo Fisher Scientific, that was diluted to 10 wt. % in water), crosslinker AS (neat liquid), and polyvinyl alcohol (POVAL 49-88, available from Kuraray Ltd., Singapore; abbreviation = "PVA") were mixed together to form the coating formulation (amounts listed in Table 17). The coating formulation was coated onto a clear PET polyester film substrate (5 mil) using a #24 Meyer rod and then dried at 85 °C for 5-10 minutes to form a clear coat. Test strips (about 25 mm by 102 mm) were prepared from the coated film.

[0112] The test strips were evaluated for color change (at 80 and 300 seconds) and for integrity of the test strip according to the procedure described for Reference Example 53. The results are reported in Table 18.EXAMPLE 70

[0113] Branched polyethylenimine (bPEI, MW 60,000 g / mole as a 50 wt. % solution in water, available from Thermo Fisher Scientific, that was diluted to 10 wt. % in water), crosslinker AS (neat liquid), and polyvinyl pyrrolidone (K90, MW = 360,000 g / mole, available from Sigma-Aldrich Corporation, abbreviation = "PVP") were mixed together to form the coating formulation (amounts listed in Table 17). The coating formulation was coated onto a clear PET polyester film substrate (5 mil) using a #24 Meyer rod and then dried at 85 °C for 5-10 minutes to form a clear coat. Test strips (about 25 mm by 102 mm) were prepared from the coated film.

[0114] The test strips were evaluated for color change (at 80 and 300 seconds) and for integrity of the test strip according to the procedure described for Reference Example 53. The results are reported in Table 18.EXAMPLES 71-75

[0115] The coating formulations for Examples 71-75 were prepared by pre-mixing branched polyethylenimine (bPEI, MW 60,000 g / mole as a 50 wt. % solution in water, available from Thermo Fisher Scientific that was diluted to 10 wt. % in water) and R966 (10 wt. % in water). With continued mixing the crosslinker AS (neat liquid) was added followed by the addition of PVA (10 wt. % solution in water). The amount of each component in a formulation is listed in Table 17. Each coating formulation was individually coated onto a separate clear PET polyester film substrate (5 mil) using a #24 Meyer rod. The coated films were dried at 85 °C for 5-10 minutes to form a clear coat. Test strips (about 25 mm by 102 mm) were prepared from the coated films.

[0116] The test strips were evaluated for color change (at 80 and 300 seconds) and for integrity of the test strip according to the procedure described for Reference Example 53. The results are reported in Table 18. TABLE 17ExamplebPEI, gR966, gAS, gPVA, gPVP, g695000.5500705000.50507150250.5250725016.70.533.30735012.50.537.507470150.71507530350.3350 TABLE 18 ExampleColor after Immersion for 80 secColor after Immersion for 300 secTest Strip Integrity69clear to very pale yellowbright yellowslight cracking and haze70not determinednot determinedslight cracking and haze71clear to very pale yellowbright yellowhaze72clear to very pale yellowbright yellowslight haze73clear to very pale yellowbright yellowhaze74pale yellowbright yellowslight haze75clear to very pale yellowbright yellowhaze EXAMPLES 76-87

[0117] The coating formulations for Examples 76-87 were prepared by pre-mixing branched polyethylenimine (bPEI, MW 60,000 g / mole as a 50 wt. % solution in water, available from Thermo Fisher Scientific, that was diluted to 10 wt. % in water) and R966 (10 wt. % in water). The crosslinkers 3-(acryloxypropyl)trimethoxysilane (abbreviation = "AS", and prepared as 10 wt. % in isopropyl alcohol) and PZ-28 (prepared as 10 wt. % in isopropyl alcohol) were added next with continued mixing to form the specified coating formulations. The amount of each component (as 10 wt. % solutions) in a formulation is listed in Table 19. Each coating formulation was individually coated onto a separate clear PET polyester film substrate (5 mil) using a #24 Meyer rod. The coated films were dried at 85 °C for 5-10 minutes to form a clear coat. Test strips (about 25 mm by 102 mm) were prepared from the coated films. The test strips were evaluated for color change (at 80 and 300 seconds), color leaching, and test strip integrity according to the procedure described for Reference Example 53. The results are reported in Table 20. TABLE 19ExamplebPEI gR966, gAS, gPZ-28, g76730.7077730.70.1578730.35079730.350.1580550.5081550.50.2582550.250.2583550.70.1584370.3085370.30.3586370.15087370.150.35 TABLE 20 ExampleColor after Immersion for 80 secColor after Immersion for 300 secTest Strip IntegrityColor from Test Strip Leached into 0.575 wt. % OPA Bath76clear to very pale yellowbright yellowno issueno77clear to very pale yellowbright yellowno issueno78clear to very pale yellowbright yellowno issueyes79clear to very pale yellowbright yellowno issueno80clear to very pale yellowbright yellowno issueno81clear to very pale yellowbright yellowno issueno82clear to very pale yellowbright yellowno issueno83clear to very pale yellowbright yellowno issueno84pale yellowbright yellowno issueno85pale yellowbright yellowno issueno86pale yellowbright yellowno issueno87pale yellowbright yellowno issueno EXAMPLES 88-92

[0118] The coating formulations for Examples 88-92 were prepared by pre-mixing branched polyethylenimine (bPEI, MW 60,000 g / mole as a 50 wt. % solution in water, available from Thermo Fisher Scientific, that was diluted to 10 wt. % in water) and R966 (10 wt. % in water). The crosslinkers 3-(acryloxypropyl)trimethoxysilane (abbreviation = "AS", and prepared as 10 wt. % in isopropyl alcohol) and PZ-28 (prepared as 10 wt. % in isopropyl alcohol) were added next with continued mixing to form the specified coating formulations. The amount of each component in a formulation (as 10 wt. % solutions) is listed in Table 21. Each coating formulation was individually coated onto a separate clear PET polyester film substrate (10 mil) using a #30 Meyer rod. The coated films were dried at 110 °C for 10 minutes to form a clear coat. Test strips (about 25 mm by 102 mm) were prepared from the coated films. A testing solution of ortho-phthalaldehyde (OPA) in water was prepared at a concentration of 0.35 wt. % OPA. The test strips were evaluated by immersing a test strip into a bath of the OPA testing solution for either 1.35 or 5 minutes with the bath temperature maintained at 25 °C. Following immersion the test strip was removed from the testing solution, immersed in a fresh bath of distilled water for 15 minutes, and then rinsed with isopropyl alcohol for about 5 seconds. The test strip was placed on a white background and the reflectance measurement of the test strip was determined at an emitted wavelength 450 nm using an X-Rite Handheld Spectrophotometer X-Rite eXact NGH Handheld Spectrophotometer with a 4 mm aperture (X-Rite Inc.). The mean reflectance values (n= 3) and corresponding test conditions are reported in Table 22. TABLE 21ExamplebPEI,R966,AS,PZ-28,gggg88550.25089370.15090730.7091730.70.1592550.50.25 TABLE 22 Test Strip of ExampleMean Reflectance, %OPA Bath Immersion Time of 1.35 MinOPA Bath Immersion Time of 5 Min88491589583490438915112925816 EXAMPLES 93-95

[0119] The coating formulations for Examples 93-95 were prepared by pre-mixing branched polyethylenimine (bPEI, MW 60,000 g / mole as a 50 wt. % solution in water, available from Thermo Fisher Scientific, that was diluted to 10 wt. % in water) and polyacrylic dispersion A612 (10 wt. % in water). The crosslinkers 3-glycidoxypropyl trimethoxysilane (GPS, neat) and PZ-28 (prepared as 10 wt. % in isopropyl alcohol) were added next with continued mixing to form the specified coating formulations. The amount of each component in a formulation is listed in Table 23. Each coating formulation was individually coated onto a separate clear PET polyester film substrate (5 mil) using a #24 Meyer rod. The coated films were dried at 85 °C for 5-10 minutes to form a clear coat. Test strips (about 25 mm by 102 mm) were prepared from the coated films. The test strips were evaluated for color change (at 80 and 300 seconds), color leaching, and test strip integrity according to the procedure described for Reference Example 53. The results are reported in Table 24. TABLE 23ExamplebPEI (10 wt. %), gA612 (10 wt. %), gGPS (neat), gPZ-28 (10 wt. %), g93730.070.1594550.050.2595370.030.35 TABLE 24 ExampleColor after Immersion for 80 secColor after Immersion for 300 secTest Strip IntegrityColor from Test Strip Leached into 0.575 wt. % OPA Bath93pale yellowbright yellowno issueno94pale yellowbright yellowno issueno95pale yellowbright yellowno issueno Reference EXAMPLES 96-97

[0120] Branched polyethylenimine (bPEI, MW 60,000 g / mole as a 50 wt. % solution in water, available from Thermo Fisher Scientific that was diluted to 5 wt. % in water) and diethyl glutaconate (Sigma-Aldrich Corporation) were mixed together to form the coating formulations (amounts listed in Table 25). Separate samples of nylon membrane (described in Example 19) were dip coated with one of the coating formulations. The coated samples were dried at 120 °C for 5 minutes to form a clear coat. Test strips (about 25 mm by 102 mm) were prepared from the coated samples.

[0121] The test strips were evaluated for color change (at 80 and 300 seconds) and for leaching according to the procedure described for Reference Example 53. In addition, the time point at which a color change of the test strip was first observed was recorded. The results are reported in Table 26. TABLE 25Reference ExamplebPEI (5 wt. %), gDiethyl glutaconate (neat), g9690.059750.25 TABLE 26 Reference ExampleTime to Initial Color Change, secondsColor after Immersion for 80 secColor after Immersion for 300 secColor from Test Strip Leached into 0.575 wt. % OPA Bath9643clear to very pale yellowbrown- yellowno9747clear to very pale yellowbrown-yellowno Reference EXAMPLE 98 and EXAMPLES 99-100

[0122] The coating formulations for reference Example 98 and Examples 99-100 were prepared by mixing ethoxylated polyethylenimine (MW 50,000 g / mole as a 37 wt. % solution in water, available from Sigma-Aldrich Corporation that was diluted to 5 wt. % in water) and 3-(acryloxypropyl)trimethoxysilane (abbreviation of "AS", Gelest Inc.) in the amounts listed in Table 27. Separate samples of nylon membrane (described in Example 19) were dip coated with one of the coating formulations. The coated samples were dried at 120 °C for 5 minutes to form a clear coat. Test strips (about 25 mm by 102 mm) were prepared from the coated samples.

[0123] The test strips were evaluated for color change (at 80 and 300 seconds) and for leaching according to the procedure described for Reference Example 53. In addition, the time point at which a color change of the test strip was first observed was recorded. The results are reported in Table 28. TABLE 27ExampleEthoxylated polyethylenimine (5 wt. %), gAS (neat), g9810099100.1100100.2 TABLE 28 ExampleTime to Initial Color Change, secondsColor after Immersion for 80 secColor after Immersion for 300 secColor from Test Strip Leached into 0.575 wt. % OPA Bath9817pale yellowbright yellowyes9956pale yellowbright yellowno10067very pale yellowbright yellowno EXAMPLE 101

[0124] The coating formulation was prepared by first mixing 7 g of branched polyethylenimine (bPEI, MW 60,000 g / mole as a 50 wt. % solution in water, available from Thermo Fisher Scientific, that was diluted to 10 wt. % in water) and 3 g of R966 (10 wt. % in water). The crosslinkers diethyl glutaconate (0.14 g, neat) and PZ-28 (0.15 g, prepared as 10 wt. % in isopropyl alcohol) were added next with continued mixing to form the coating formulation. The formulation was coated onto a clear PET polyester film substrate (10 mil) using a #24 Meyer rod. The coated film was dried at 120 °C for 5 minutes to form a clear coat. Test strips (about 25 mm by 102 mm) were prepared from the coated films. Test strips were evaluated for color change (at 80 and 300 seconds), color leaching, and test strip integrity according to the procedure described for Reference Example 53. The results are reported in Table 29, below. TABLE 29ExampleColor after Immersion for 80 secColor after Immersion for 300 secTest Strip IntegrityColor from Test Strip Leached into 0.575 wt. % OPA Bath101clear to very pale yellowbright yellowno issueno EXAMPLE 102

[0125] The coating formulation was prepared by first mixing 6.3 g of branched polyethylenimine (bPEI, MW 60,000 g / mole as a 50 wt. % solution in water, available from Thermo Fisher Scientific, that was diluted to 10 wt. % in water) and 2.7 g of R966 (10 wt. % in water). The crosslinkers 3-(acryloxypropyl)trimethoxysilane (0. 63 g of a 10 wt. % solution in isopropyl alcohol) and PZ-28 (0.14 g of a 10 wt. % in isopropyl alcohol) were added next with continued mixing. Finally, 1 g of Nalco 1115, aqueous silica nanoparticle dispersion (spherical, 4 nm, 15 wt. %; available from Nalco Company, Naperville, Illinois) was added with mixing to form the coating formulation. The formulation was coated onto a clear PET polyester film substrate (10 mil) using a #24 Meyer rod. The coated film was dried at 120 °C for 5 minutes to form a clear coat. Test strips (about 25 mm by 102 mm) were prepared from the coated films. The test strips were evaluated for color change (at 80 and 300 seconds), color leaching, and test strip integrity according to the procedure described for Reference Example 53. The results are reported in Table 30.EXAMPLE 103

[0126] A modified silica nanoparticle dispersion was prepared by adding with mixing 1.77 g of 3-aminopropyltriethoxysilane (Sigma-Aldrich Corporation) was added with mixing to 50 g of a 10 wt. % Nalco 1115 aqueous silica nanoparticle dispersion. The resulting dispersion was heated at 80 °C for 12 hours and then cooled to room temperature.

[0127] The coating formulation was prepared by first mixing 6.3 g of branched polyethylenimine (bPEI, MW 60,000 g / mole as a 50 wt. % solution in water, available from Thermo Fisher Scientific, that was diluted to 10 wt. % in water) and 2.7 g of R966 (10 wt. % in water). The crosslinkers 3-(acryloxypropyl)trimethoxysilane (0.63 g of a 10 wt. % solution in isopropyl alcohol) and PZ-28 (0.14 g of a 10 wt. % in isopropyl alcohol) were added next with continued mixing. Finally, 1 g the modified silica nanoparticle dispersion (described above) was added with mixing to form the coating formulation. The formulation was coated onto a clear PET polyester film substrate (10 mil) using a #24 Meyer rod. The coated film was dried at 120 °C for 5 minutes to form a clear coat. Test strips (about 25 mm by 102 mm) were prepared from the coated films. The test strips were evaluated for color change (at 80 and 300 seconds), color leaching, and test strip integrity according to the procedure described for Reference Example 53. The results are reported in Table 30, below. TABLE 30ExampleColor after Immersion for 80 secColor after Immersion for 300 secTest Strip IntegrityColor from Test Strip Leached into 0.575 wt. % OPA Bath102pale yellowbright yellowno issueno103clear to very pale yellowbright yellowno issueno EXAMPLES 104-107

[0128] The coating formulations for Examples 136-139 were prepared by pre-mixing branched polyethylenimine (bPEI, MW 60,000 g / mole as a 50 wt. % solution in water, available from Thermo Fisher Scientific, that was diluted to 5 wt. % with added ethanol) with a 5wt. % ethanol solution of SR415 multifunctional acrylate (20 mole ethoxylated trimethylolpropane triacrylate, Sartomer Corporation). Next a 5 wt. % solution of the photoinitiator IRGACURE 184 (1-hydroxycyclohexyl phenyl ketone, BASF Corporation, Florham Park, New Jersey) in ethanol was added with mixing followed by the optional addition of a 5 wt. % solution of R966 in ethanol with continued mixing. The amount of each component in a formulation is listed in Table 31. Each of the resulting coating formulations was individually coated onto a separate clear PET polyester film substrate (5 mil) using a #24 Meyer rod. The coated films were dried at 100 °C for 5 minutes and then cured under a nitrogen atmosphere by 3 passes through a UV curing station (model MC-6RQN, Fusion UV Curing Inc., Rockville, MD) with a Fusion "H" lamp at a speed of 12.2 meters / minute to form a clear coating. Test strips (about 25 mm by 102 mm) were prepared from the coated films. The test strips were evaluated for color change (at 80 and 300 seconds), color leaching, and test strip integrity according to the procedure described for Reference Example 53. The results are reported in Table 32. TABLE 31ExamplebPEI (5 wt. %), gSR415 (5 wt. %), gR966 (5 wt. %), gIRGACURE 184, mg10491010105730301068.51.54.315107334.430 TABLE 32 ExampleColor after Immersion for 80 secColor after Immersion for 300 secTest Strip IntegrityColor from Test Strip Leached into 0.575 wt. % OPA Bath104clear to very pale yellowbright yellowno issueno105clear to very pale yellowbright yellowno issueno106clear to very pale yellowbright yellowno issueno107clear to very pale yellowbright yellowno issueno

Claims

1. A composition comprising a compound preparable by reaction of components comprising a polyethylenimine and at least one an amine-reactive hydrolyzable organosilane represented by the formula:         R-Z-SiY3 wherein: R represents an amine-reactive group containing 1 to 18 carbon atoms, wherein R is selected from the group consisting of an isocyanato group, an acryloxy group, a carboethoxy group, a carbomethoxy group, a vinylsulfonyl group, and an acrylamido group; Z represents a divalent organic group containing 1 to 8 carbon atoms; and each Y independently represents a hydrolyzable group; and wherein the composition further comprises a polymeric binder material.

2. The composition of claim 1 comprising a crosslinked polyethylenimine, wherein the polyethylenimine is a crosslinked polyethyleneimine.

3. The composition of claim 2, further comprising an aqueous liquid vehicle in which the compound is dispersed or dissolved.

4. The composition of claim 2, wherein R has from 1 to 3 carbon atoms.

5. The composition of claim 2, wherein Z further contains from 1 to 6 heteroatoms selected from the group consisting of O, N, and S.

6. The composition of claim 2, wherein Z comprises an alkylene group containing 1 to 3 carbon atoms.

7. The composition of claim 2, wherein each Y is independently selected from methoxy, ethoxy, hydroxy, acetoxy, chlorine, and bromine.

8. The composition of claim 2, wherein the at least one an amine-reactive hydrolyzable organosilane is selected from the group consisting of 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, 2-isocyanatoethyltriethoxysilane, 2-isocyanatoethyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 2-acryloxyethyltriethoxysilane, 2-acryloxyethyltrimethoxysilane-9. The composition of claim 2, further comprising a polymeric binder material selected from polyvinyl alcohol hydroxyethyl cellulose, hydroxypropyl cellulose.

10. An article comprising: a substrate having a surface; and a crosslinked reaction product of a composition according to claim 8 disposed on at least a portion of the surface.

11. A composition comprising a mixture of a crosslinked polyethylenimine and a polymeric binder material, wherein the crosslinked polyethylenimine is a reaction product of polyethyleneimine and an acrylic monomer having at least two acryl groups, and wherein the crosslinked polyethylenimine and the polymeric binder material are dispersed or dissolved in an aqueous liquid vehicle.

12. A method of making the composition of claim 11, the method comprising sequentially mixing: an aqueous solution of polyethylenimine; a crosslinker for the polyethylenimine; and a polymeric binder material, wherein the crosslinker for the polyethylenimine comprises an acrylic monomer having at least two acryl groups.