RE-LATED APPLICATIONS
This application claims priority from U.S. Provisional Application Serial No,
61/222,652 entitled "Film Sensors and Methods for Making" tiled on July 2, 2009, tlie
entirety of which is incorporated.
FIELD OF THE INVENTION
The present invention relates to sensor films for measuring water-soluble polymers in
industrial water systems and, more particularly, for multiple-component sensor films
for measuring water-soluble polymers in industrial water systems,
BACKGROUND OF THE INVENTION
Additives, such as water-soluble polymers, aie often added to industrial water systems
for inhibiting sc^le formation on processing equipment. The concentration of the
water-soluble polymers can be monitored, such as with an optical sensor, to ensure an
optimal concentration range. One type of optical sensor that can be used is a sensor
film containing an indicator, which reacts with water-soluble polymers to detect and
measure their concentration.
Water-soluble polymers can be ver>' large molecules and cannot readily diffuse into a
tlhn for contact with the indicator. Dissolvable sensor films contain a water-soluble
matrix and an indicator and casi be used for detecting polymers or large molecules.
Upon contact with the water to be tested, the water-soluble matrix dissolves and
releases the indicator into the water to interact with the water-soluble polymer.
Additional components, such as masking agents, buffer solutions and stabilizers are
often needed to optimize detection of the water-sduble polymer, it i.s difficult to
prepare stable multiple-component dissolvable films as the components can interact
with one another to form insoluble precipitates and settle or phase separate out of the
film mixture.
2-
It would be desirable to obtain a multicomponent dissolvable sensor film for
measuring water-soluble polymers in aqueous systems.
SUMMARY OF THJ?; INVEiNTION
in one embodiment, a sensor film includes a carrier polymer matrix and film reactants
dispersed within the carrier polymer matrix, the carrier polymer matrix includes a
carrier polymer including hydroxypropyl cellulose polymer and the film reactants
include an indicator and at least one reactant selected fi^om the group consisting of a
pH buffer, a stabilizer, a masking agent, an internal reference dye aiid a solubilizer.
In another embodiment, a method for making a sensor film includes blending an
aqueous hydroxypropyl cellulose polymer solution with an indicator to make a first
blend, blending an aqueous hydroxypropyl cellulose polymer solution with at least
one film reactant selected from the group consisting of a pH buffer, a stabilizer, a
masking agent, an internal reference dye and a solubilizer to make a second blend,
mixing the first and second blends to make a film solution and forming a film from
the film solution.
In another embodiment, a method for monitoring the concentration of water-soluble
polymers in aqueous media including contacting the aqueous media with a sensor
film, measuring a response from an indicator and equating the response with a
concentration amount, wherein the sensor film includes a carrier polymer matrix and
film reactants dispersed witWn the earner polymer matrix, the canier polymer matrix
including a carrier polymer including hydroxypropyl cellulose polymer and the film
reactants including the indicator and at least one film reactant selected from the group
consisting of a pH buffer, a stabilizer, a masking agent, an internal reference dye and
a solubilizer, whereby the carrier polymer matrix dissolves in tlie aqueous media and
releases the film reactants into the aqueous media.
The various embodiments provide stable multicomponent dissolvable films for
detecting and measuring the concentiation of water-soluble polymers in industrial
water systems.
3
BRIEF DESCRIPTION OF DRAWINGS
Figure i is a graph showing the color response for water-soluble polymers relative to
amounts of the water-soluble polymers. The graph is color response, which is an
absorbance measurement of (Red Absorbance * Yellow Absoii>ance) / (Green
Absottance squared) vs. the amount of HPSl or PESA in parts per million by weight
(ppm).
DETAILED DESCRIPTION OF THE INVENTION
The singular forms "a," "an" and "the" include plural referents unless the context
clearly dictates otherwise. The endpoints of all ranges reciting the same characteristic
are independently combinable and inclusive of the recited endpoini. All references
are incorporated herein by reference.
The modifier "about" used in connection with a quantity is inclusive of tlie stated
value and has the meaning dictated by the context (e.g., includes the tolerance ranges
associated with measurement of the particular quantity).
""Optional" or ''optionally" means that the subsequently described event or
circumstance may or may not occur, or that the subsequently identified material may
or may not be present, and that the description includes instances where the event or
circumstance occurs or where the material is present, and instances where the event or
circumstance does not occur or the material is not present.
In one embodiment, a sensor film includes a carrier polymer matrix and film reactants
dispersed within the carrier polymer matrix, the canier polymer matrix including a
carrier polymer including hydroxypropyl cellulose polymer and the film reactants
include an indicator and at least one reactant selected from tlie group consisting of a
pll buffer, a stabilizer, a masking agent, an internal reference dye and a solubilizer.
The sensor film can be used in industrial water systems to detect and measure the
concentration of water-soluble polymers that may be added to aqueous media in the
industrial water systems. The industrial water systems may be cooling towers,
boilers, evaporators, gas scrubbers, kilns or desalination units and the aqueous media
may be any type of aqueous solutions or water. Water-soluble polymers, including
water-soluble biopolymers, may be added to aqueous media in the industrial water
systems a$ dispersants, corrosion inhibitors or other types of additives to protect tlie
processing eciuipment. In one embodiment, the water-soluble polymers are anionic
water-soluble polymers, which contain an anionic group. In one embodiment, the
anionic group may include, but is not limited to, carboxylate, sulfonate, sulfate,
phosphonate or phosphate. Anionic water-soluble polymers that may be added to
aqueous media in the industrial water systems include, but are not limited to,
polyacrylic acid and derivatives of polyacr>'lic acid, polysulfonated polymers or
maleic anhydride polymers. In anod^er embodiment, the anionic water-soluble
polymers may include poly(aciylic acid-co-1-allyloxy-2-hydroxypropylsulfonate
(HPvS-l), poly(aci7lic acid-co-l-allyloxy-polyethylene oxide sulfate), poly(aci7lic
acid-co-1-allyloxy-polyelhylene oxide sulfate-co-l-allyloxy-2-hydroxy propyl
sulfonate) or polyepoxysuccinic acid (PESA).
Many of the water-soluble polymers are large molecules with long chains, which
make diffusion into a film difficult. Sensor films are dissolvable films having a
water-soluble carrier polymer matrix, which allows the film reactants to interact with
the water-soluble polymers in the aqueous media. The carrier polymer matrix
includes a hydroxypropyl cellulose polymer (IICP), which is soluble in water and
inert to reactions with tlie water-soluble polymers being detected.
Ihe canier polymer matrix includes a carrier polymer, which includes HCP. HCP is
used to form the carrier polymer matrix tor the film and provides support for the film
reactants, which are dispersed within the carrier polymer matrix. In one embodiment,
the carrier polymer matiix may be fonned by any conventional manner. In one
embodiment, the carrier polymer matrix may be formed by preparing a film from the
HCP. In one embodiment, a film may be made by any means known in the art.
Examples of preparing a film are described subsequently.
The film reactants are dispersed within the carrier polymer matrix and are released
into the aqueous media being tested when the carrier polymer dissolves upon contact
with the aqueous media enabling the film reactants to interact with the water-soluble
5
polymers in the aqueous media. In one embodiment, the film reactants are dispersed
within the carrier polymer matrix by blending the film reactants with the carrier
polymer. In another embodiment, the film reactants are dispersed within the carrier
polymer matrix by blending the film reactants in solution. In another embodiment,
the film reactants are blended with the carrier polymer and formed into a film.
In one embodiment, the film reactants include an indicator, which changes its optical
properties upon reaction with a water-soluble polymer. In one embodiment, the
indicator changes its light absorption or emitting properties and the change can be
detected by visible, ultraviolet, infrared or fluorescence absorption, transmission or
emisvsion or where changes from cleai- or transparent to cloudy or opaque can be
detected by light scattering.
In one embodiment, the indicator is a dye, such as organic dyes, organic fluorophores,
fluorescent dyes, IR absorbing dyes, UV absorbing dyes, photochromic dyes,
thermochromic dyes, sulphonephthalein dyes, and other known dyes that may be used
for this purpose. In one embodiment, the dyes may include, but are not limited to,
bromothymol blue, bromocresol green, bromopyrogallol red, .xyiidyl blue I,
chlorophosphonazo III, brilliant green, xanthene dyes, such as rhodamine B,
rhodamine 6G, eosine, phloxine B and the like, acridine dyes, such as acridine orange,
acridine red and the like, azo dyes, such as ethyl red, methyl red and the like,
porphyrin dyes, phthaiocyanine dyes, cyanine dyes, such as 3,3'-
diethylthiacai-bocyanine iodide, 3,3'-diethyloxadicarbocyanine iodide and the like,
merocyanine dyes, styry'l dyes, oxonol dyes, triarylmethane dyes, methylene blue,
phenol blue and the like. Examples of IR absorbing dyes include carbCHi black and
Poly{styrenesulfonate)./poly(2,3-dihydrothieno{3,4-b>l,4-dioxin).
In another embodiment, the dye may be a cationic dye. In one embodiment, tlie dye
may be 1,9-dimethyl methylene blue (DMMB), brilliant crystal blue, Basic Blue 17,
New Methylene Blue, Azure B or cwibinations thereof
The indicator is present in any amount suitable for detecting a water-soluble polymer.
In one embodiment, the indicator is present from about 0.5 moles to about 3.0 moles
per mole of the water-soluble polymer. In another embodiment, the indicator is
present in an amount of from about 0.1 percent by weight to about 10 percent by
weight, based on the weight of the cairier polymer. In another embodiment, tlie
indicator is present in an amount of from about 0.5 percent by weight to about 5
percent by weight, based on the weight of the carrier polymer. In another
embodiment, the indicator is present in an amount of from about 0.5 percent by
weight to about 3 percent by weight, based on the weight of the carrier polymer.
The tllm reactants may include additional components to enhance the detection and
quantitative measurements of the water-soluble polymers. In one embodiment, tlie
film reactants may include at least one reactant selected from the group consisting of
pH buffers, stabilizers, masking agents, internal reference dyes and solubilizers.
Many indicators have specific active pH ranges in which the indicator performance is
maximized. The pH buffers may be used to adjust the pH of the aqueous media being
analyzed to a specific pH range. The pH buffer may be any type of water-soluble
buffer, In one embodiment, the buffer includes, but is not limited to, N~(2-
acetamido)-2-aminoetbanesulfonicacid, 2-(caibamoylmethylamino)ethanesulfonic
acid butTer, boric acid, acetic acid, sodium hydroxide, 2-(NMofpholino)
ethanesulfonic acid hydrate/4-Morpholineethaiiesuifonic acid, 2,2-
Bis(hydroxymethy1)-2,2',2"-nitriiotriethanoi/2-Bis(2-hydroxyethyl)amino-2-
(hydroxymethyi)-1,3-propanediol/Bis(2-hydroxyetliy!)aminotris(
hydroxymethyl)methane, N-(2-AcetamJdo)iminodiacetic acid/ N-
(Carb^noylmethyl)iminodiacetic acid, N-(2-Acetamido)-2-aminoethanesulfonic acid/
N-(Carbainoylmetfayl )-2-arainoethanesulfoaic acid/N-(Carbainoylmethyl)taurine, 1,4-
Pi perazi nediethanesulfonic aci d/Kperaidne-1,4-bi s(2-ethanesulfonic acid)/Piperazine-
N,N'-bis(2-ethanesu1fonic acid), p-Hydroxy-4-morpho1inepropanesulfonic acid/3-
Morpholino-2-hydroxypropanesulfonic acid, 1,3-
Bis[tris(hydroxymethy1)methylanunoJpropane, N,N-Bis(2-hydroxyethyl)-2-
aminoethanesulfonic acid/N,N-Bis(2-hydroxyethyI)taurine, 3-(NMorpholino)
propanesulfonic acid/4-Morphoiinepropanesulfonic acid, N-
[ rris(hydroxymethyl)methyl]-2-aminoethanesu!fonic acid/2-[(2-Hydroxy-1,1 -
bis(hydroxymethyl)ethy l)an)inojethanesu]fonic acid, 4-(2-JIydroxyethy})piperazine-1 -
7
ethanesulfonic acid/N-(2-Hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid), 3-
(N, N -lii s[2-hy droxyethy! Jaini no)-2-hydroxy propanesulfoni c aci d/ N, N -B i s{2-
hydroxyethyl)-3-ai'nino-2-hydroxypropanesulfonic acid, 4-(NMorpholino)
butanesulfonic acid, 2-Hydroxy-3-[tris(hydroxymethyl)mt'thylaminol-1-
propanesulfonicacid/N-[Tris(hydroxymetliyl)methyl]-3-amino-2-
hydroxypropanesulfonic acid, 2-Anutio-2-(hydroxymethyl)-1,3-
propanediol/'rris(hydroxymethy!)aminomethane/"rrometamol, 4-(2-
Hydroxyethyl)piperazine-1-(2-hydroxypropanesulfonic acid) Hydrate, Pipera2ine-1,4-
bi.s(2-hydroxypropanesulfonicacid)dihydrate/Pipera/Jne-N,N'-bis(2-
hydroxypropanesulfontc acid), Tris-EDTA-Acetate, 4-(2-HydtX)xyethyl)-lpi
perazi nepropanestilfonic acid/4-{2-il!y droxyelhyl)pi perazlne-1 -propanesul foni c
acid/ HEPPS/N-(2-Hydroxyethyl)pipera;rine-N'-(3-propaiiesuifonic acid), N-
[Tris(hydroxymethy!)methyl]glycine,DigIycine/Glycyl-glycine,N,N-Bis(2-
liydroxyethyl)giycine, N-(2-Hydroxyethyr)piperazine-N'-(4-butanesulfonic acid), N-
[Tris(hydroxyniethy})methyl]-3-aminopropanesulfonic acid/[(2-Hydroxy-1,1 -
bis(hydroxymethyl)ethyl)aniinoj-] -propaiiesulfonic acid, 2-Amino-2-methyl-l ,3-
propanediol, N-tris(Hydroxymethyi)methy1-4-aminobutanesulfonic acid, N-(l,l-
I>imethyl-2-hydroxyethyi)-3-attiino-2-hydroxypropanesulfonicacid, 2-
(Cyclohexy1amino)ethanesu{fonic acid, 3-(Cyc!ohexylaitiino)-2-hydroxy-lpropanesulfonic
acid, 2-Amino-2-methyl-l-propanol, 3-(Cyclohexylamtno)-ipropanesulfonic
acid, 4-(Cyclohexyiamino)-l-butanesulfonic acid and mixtures
thereof
In one embodiment, a pH buffer is used to adjust the aqueous media to be tested to a
• pH in the range from about 3 to about 10. In another embodiment, the pH is adjusted
in the range of from about 6 and to about 8. In another embodiment, the pH is
adjusted to a pH of about 1.
The pll. butler is added in any amount sulTjcient to adjust the plJ of the aqueous
media. In one embodiment, the pH buffer is present in an amount of from about I
percent by weight to about 50 percent by weight, based on the weight of the carrier
polymer. In another embodiment, tlie pH buffer may be present in an amount of from
about 10 percent by weight to about 30 percent by weight, based on the weight of the
carrier polymer. In another embodiment, the pH buffer may be present in an amount
of from about 10 percent by weight to about 20 percent by weight, based on the
weight of the carrier polymer.
In one embodiment, the film reactant may include a stabilizer. The stabilizer may be
used to maintain the solubility of the film reactants in the aqueous media. Once
dispersed within the aqueous media, the film reactants can react with other film
reactants or with components in the aqueous media to form insoluble precipitants. A
stabilizer inhibits precipitates from forming by associating with any minimally soluble
material to form complexes that remain soluble in the aqueous media. In one
embodiment, the stabili/er may be Arabic gum. In another embodiment, the amount
of stabilizer may be in amount up to about 100 ppm by weight, based on the weight of
the carrier polymer. In another embodiment, the stabilizer may be in an amount of
from about 10 ppm to about 100 ppm by weiglit, based on the weight of the carrier
polymer. In another embodiment, the stabilizer may be in an amount of from about
30 ppm by weight to d)out 50 ppm by weight, ba.<5ed on the weight of the carrier
polymer.
Other types of additives or other water-soluble polymers may be added to the
industrial water systems for protecting the processing equipment or treating the
aqueous media. These oUter additives or other water-soluble polymers can interfere
with the measurement of a specific water-soluble polymer by reacting with the
indicator and affecting a change in tlie optical properties. In one embodiment,
masking agents are used to block the reactions from other types of additives or watersoluble
polymers without inhibiting the reaction between the indicator and a specific
water-soluble polymer to be measured.
For example, polyepoxysuccinic acid (PESA) may be added in a mixture with HPS-1
to the aqueous media, Botli of these polymers can react with the indicator that is used
to measure polymer concentrations and, consetiuently, the measured change in optical
properties of the indicator is a function of the total polymer concentration and not of
the HPS-1 concentration alone.
7
In one embodiment, the masking agent is a salt or a cationic surfactant. In one
embodiment, the masking agent includes, but is not limited to, bivalent manganese
salt, ferrous salt, calcium salts, zinc salts, quaternary' amine surfactant or
combinations thereof. In another embodiment, the calcium salt may be calcium
chloride.
In one embodiment, the masking agent may be added in any amount suitable for
masking the response from another additive. In one embodiment, the masking agent
is present in an amount up to about 2000 ppm by weight, based on the weight of the
eerier polymer. In another embodiment, the masking agent is from about 20 ppm to
about 2000 ppm by weight based on the weight of the carrier polymer. In another
embodiment, the masking agent may be present from about 100 ppm to about 1000
ppm by weight, based on the weight of the carrier polymer.
In one embodiment, the film reactant may include an internal reference dye, which
helps to offset indicator irregularities. A film may have irregularities in thickness
across the film and may contain non-unifonn amounts of indicator across the film.
An internal reference dye is not reactive with the waier-soluble polymers to be
measured, but mil indicate tlte presence of extraneous measurements, such as
irregularities in the amount of indicator, which can be used to adjust the measurement
readings of the water-soluble polymers. The internal reference dye may be any type
of internal reference dye known in tlie art. In one embodiment, the internal reference
dye may be tris(2,2-bipyridy{)dichloronithenium(ll) hexaltydrate. In another
embodiment, the internal reference dye is present in any amount suitable for offsetting
irregularities in the film. In anotlter embodiment, the internal reference dye is present
from about 0.1 percent by weight to about 2.5 percent by weight, based on the weight
of the carrier polymer.
In one embodiment, the film reactant may include a solubilizer to enhance
solubilization of the film reactants in the aqueous media. In one embodiment, the
solubilizer may be any type of solubilizer known in the art. In another embodiment,
the solubilizer may be fine silica. In one embodiment, the solubilizer may be present
in any amount suitable for enhancing solubility of the film reactants in the aqueous
media. In another embodiment, the solubilizer is present in an amount of from about
0.1 percent by weight to about 5 percent by weight, based on the weight of the carrier
polymer.
In another embodiment, a method for making a sensor film inchiding blending an
aqueous hydroxypropyl cellulose polymer solution with an indicator to make a first
blend, blending an aqueous hydroxypropyl cellulose polymer solution with at least
one component selected from the group consisting of a pH buffer, a stabilizer, a
masking agent, an internal reference dye and a solubilizer to make a second blend,
mixing the first and second blends to make a film solution and forming a film from
the film solution. In one embodiment, a first blend is prepaied by blending JICP with
an indicator. The HCP and indicator are described above. In one embodiment, the
HCP and indicator are blended in any suitable manner known in the art. In one
embodiment, the HCP and indicator aie blended in an aqueous solution. In another
embodiment, the aqueous solution is a water solution. In one embodiment, the HCP
is present in an aqueous HCP solution from about I percent by weight to about 12
percent by weight, based on the total volume of water. In another embodiment, the
HCP is present in an aqueous HCP solution from about 5 percent by weight to about
10 percent by weight, based on the total volume of water.
In another embodiment, a second blend is prepared by blending HCP with a film
reactant selected from the group consisting of pH buffers, stabilizers, masking agents,
internal reference dyes and solubilizers. The HCP and the film reactants are described
above. In one embotliment, the HCP and at least one film reactant are blended in any
suitable manner known in the art. In one embodiment, the HCP and the film reactant
are blended in an aqueous solution. In another embodiment, the aqueous solution is a
water solution. In one embodiment, the HCP is present in an aqueous HCP solution
from about 1 percent by weight to about 12 percent by weight, based on the total
volume of water. In another embodiment, the HCP is present in an aqueous HCP
solution from about 5 percent by weight to about 10 percent by weight, based on the
total volume of water.
n
Additional film reactants may also be blended into the second blend. In one
embodiment, a pM buffer and a masking agent are blended with the aqueous HCP
solution to form a second blend. In another embodiment, a pH buffer and a stabilizer
are blended with the aqueous HCP solution to form a second blend. In another
embodiment, a masking agent and a stabilizer are blended with the aqueous HCP
solution to form a second blend. In another embotliment, a pIT buffer, a masking
agent and a stabilizer are blended with the aqueous HCP solution to form a second
blend.
In one embodiment, the first and second blends are mixed together to form a film
solution and may be mixed in any manner knowji in the art. In one embodiment, the
first blend and the second blend are mixed in a 1:1 volume ratio. In another
embodiment, the first blend may be present in the film solution from about 40 percent
by volume to about 60 percent by volume, based on the total volume of the film
solution. In another embodiment, the second blend may be present in the film
solution in an amount of from about 60 percent by volume to about 40 percent by
volume, based on the total volume of the film solution.
In anodier embodiment, the film solution is formed into a film. A film may be
prepared fiora the film solution in any suitable manner known in the art. In one
embodiment, a film may be made by coating a glass or plastic substrate with the
solution and removing the solvent from the coating to produce a dry thin film. In one
embodiment, the coating may be applied to the substrate by spin coating or by dip
coating or by other means known in the art. In another embodiment, a production
slot-die coater may be used.
In one embodiment, the solvent may be removed from the coating by drying the
coating or evaporating the solvent to form a film. In one embodiment, the coating is
allowed to dry at room temperature in the air or may be heated to a temperature of up
to about 90^. In another embotUment, the coating is heated from about 30X to
about 90°C. In a.nother embodiment, the coating is heated from about SOT to about
70T. The coating may be dried for any length of time sufficient to evaporate the
solvent from the coating. In one embodiment, the coating is dried from about I
12-
minute to about 5 hours. In another embodiment, the coating is allowed to diy from
about 1 minute to about 1 hour. In another embodiment, the coating is allowed to dry
from about 1 minute to about JO minutes.
In one embodiment, the film thickness is from about 0.1 to about 50 microns. In
another embotUment, the film thickness is from about 0.5 to about 20 microns. In
another embodiment, the film thickness is from about 1 to about 10 microns. In
another embodiment, the film thickness may be from about 3 microns to about 20
microtis.
The film can be fonned to fit a specific dimension or shape. In one embodiment, the
film is formed to fit a testing structure. In another embodiment, the film is
incorporated into an optical sensor anay system, such as is described in U.S.
Published Application No. 2007-0092407, which is incorporated herein by reference.
In another embodiment, a method for monitoring the concentration of water-soluble
polymers in aqueous media including contacting the aqueous media with a sensor
film, measuring a response from an indicator and equating the response with a
concentration amount, wherein the sensor film includes a eerier polymer matrix and
film reactants dispersed within the carrier polymer matrix, the carrier polymer matrix
including a carrier polymer including hydro,xypropyl cellulose polymer, the film
reactants including the indicator and at least one film reactant selected from the group
consisting of a pH buffer, a stabilizer, a masking agent, an internal reference dye and
a solubilizer, wherd)y the carrier polymer matrix dissolves in the aqueous media and
releases the film reactants into the aqueous media.
I'he sensor film can be used in industrial water systems to detect and measure
concentrations of water-soluble polymers in the aqueous media. The concentradons
of the water-soluble polymers may be monitored to ensure tliat desired levels of the
water-soluble polymers are maintained. Water-soluble polymers are described above
and may be added to aqueous media as additives for industrial water systems. The
aqueous media may be any type of water or other aqueous solution.
13
The sensor film contacts the aqueous media to measure the concentrations of watersoluble
polymers that may be in the aqueous media. The sensor film contacts the
aqueous media in any suitable manner. In one embodiment, the sensor film is added
to the aqueous media. In another embodiment, the sensor film may be placed in an
optical sensor system, such as an optical sensor array system, and the aqueous media
Is added to the optical sensor system in contact with the sensor film. Upon contact
with the aqueous media, the sensor film dissolves in the aqueous media and releases
the indicator and other film reactants into the aqueous media where the film reactants
can interact with water-soluble polymers in the aqueous media.
As the indicator interacts with water soluble polymers in the aqueous media, the
indicator changes its optical properties and elicits a response, which can be measured.
In one embwJiment, the indicator changes its light absoqstion or emitting properties
and the change can be detected and measured by visible, ultiaviolet, infrared or
fluorescence absorption, transmission or emission or where changes from clear or
tran.sparent to cloudy or opaque can be detected by light scattering. In one
embodiment, the indicator changes color upon interaction with a water soluble
polymer aiid tlie color response can be measured with visible absorbance by
calculating (Red Absorbance * Yellow Absottance) / (Green Absorbance squared).
The response measurement may be equated with a concentration amount of the water
soluble polymers in the aqueous media. In one embodiment, a calibration curve may
be prepared for a selected indicator from knovm concentration amounts of water
soluble polymers to measured indicator responses. In another embodiment, a
calibration curve is obtained by meaasring the absorbance for a specific indicator's
color response to known concentrations of water soluble polymers in aqueous media.
The carrier polymer matrix, carrier polymer, hydroxypropyl cellulose polymer (HCP),
film reactants, indicator, pH butler, stabilizer, masking agent, internal reference dye
and solubilizer are described above. The film reactants are dispersed within the
carrier polymer matrix. In one embodiment, the film reactants are dlspeised within
the carrier polymer matrix by blending the film reactants with the carrier polymer. In
another embcKliment, the film reactants are dispersed within the carrier polymer
matrix by blending the film reactants in solution. In another embodiment, the film
reactams are blended with the carrier polymer and formed into a film.
Monitoring of the concentrations of water soluble polymers in aqueous media may be
obtained continuously or in batch testing.
In order that those skilled in the art will be better able to practice the present
disclosure, the following examples are given by way of illustration and not by way of
limitation.
EXAMPLES
COMPARATIVE EXAMPLE 1
A stock solution of HCP was prepared by adding HCP to deionixed water at a 10%
w/v ratio and stirred vigorously with a Teflon stirrer for about 24 hours under a
nitrogen blanket until the HCP was completely dissolved.
A salt stock solution was prepared by adding 975.5 g of calcium chloride dihydrate to
1500.8 g of deionized water and stirred vigorously tor 15 minutes.
39.29g of DMMB dye, 504.83g of N-(2-Acetamido)-2-aminothanesulfonic acid
(ACES) buffer and 2217.96 g of the calcium chloride dihyrate stock solution were
added to the HCP stock solution and mixed for 24 hours under a nitrogen atmosphere.
A mixture of calcium chloride salt and ACES buffer of unknown relative composition
precipitated out of solution and could not be redissolved.
EXAMPLE 2
A stock solution of HCP was prepared by adding HCP to deionized water at a 10%
w/v ratio and stirred vigorously with a Teflon stirrer for abcnit 24 hours until the HCP
was completely dissolved. The stock solution was split into two halves in separate
reactor vessels that were sparged with nitrogen. Each vessel was equipped with a
glass or Teflon stirrer and a nitrogen blanket.
A salt stock solution was prepared by adding 975.5 g of calcium chloride dihydrate to
1500.8 g of deionized water and stirred vigorously for 15 minutes.
39.29g of DMMB dye was mixed with 18,858.2Ig of the HCP stock solution in the
fjret vessel for 6 hours under a nitrogen atmosphere until homogenous to yield a first
blend. 504.83g of N-<2-Acetamido)-2-ani!ntoethanesulfonic acid (ACES) pH buffer
was mixed with 16,731.33g of the HCP stock solution in the second reactor vessel
blanketed with nitrogen for 6 hours until homogenous to yield a second blend.
2217.96 g of the calcium chloride dihyrate stock solution was also mixed with the
second blend as a masking agent for 2 hours under a nitrogen ahtjosphere until
homogenous. The second blend was charged to the first blend and mixed for 6 hours
under a nitrogen atmosphere to yield a film solution.
A dry thin film was prepared from the film solution by coating a Dr. Blade and was
dried in an oven at 70°C for 5 minutes. The film had a thickness of 5.5 micrometers.
EXA.MPI.,E 3
Several sensor films were prepared as in Example 2 having thicknesses ranging from
4-20 micrometers, and were used to prepare a calibration curve for quantifying IIPS-
1. The films were placed in an optical sensor array system and water samples were
added to the system with the films for testing. The films dissolved in the water
samples and the color response of the dye was measured. Absorbance for each
sample was mea^red with a Biotek Power Wave PS PWA reader. The color
response was calculated from the absorbance measurements with the foilovving
equation: (Red Absorbance * Yellow Absorbance)./ (Green Absorbance squared).
Water samples were prepared by mixing varying amounts of water-soluble polymers
in the water. The water samples were (1) blank v«ter samples containing no PESA or
HPS-1, (2) water samples containing vajying amounts (ppm by weight) of PESA
without any HPS-1, (3) water samples containing varying amounts (ppm by weight)
of HPS-1 without any PESA, and (4) water samples containing varying amounts (ppm
by weight) of a l l by weight blend of HPS-l and PESA. The polymer film
responses for these water samples in groups (2) -(4) were measured against the blank
water samples and are shown in Figure 1.
The film measured the MPS-1 polymer and masked tlie PE-SA polymer. There is a
slight difference noted in the curves for the water sample containing only HPS-1 and
the water sample containing a blend of HPS-1 and PES A, but the diftlerence is well
within the limits of statistical error.
While t>'pical embodiments have been set forth for the purpose of illustration, the
foregoing descriptions should not be deemed to be a limitation on the scope herein.
Accordingly, various modifications, adaptations and alternatives may occur to one
skilled in the art without departing from the spirit and scope herein.

WE CLAIM :
1. A sensor film comprising a carrier polymer matrix and film reactants
dispersed within the carrier polymer matrix, the earner polymer matrix comprising a
carrier polymer comprising hydroxypropyl cellulose polymer and the film reactants
comprising an indicator and at least one reactant selected from the group consisting of
a pH buffer, a stabilizer, a masking agent, an internal reference dye and a solubilizer.
2. The sensor film of claim 1 wherein the indicator is a dye.
3. The sensor film of claim 1 wherein tlie indicator is present in an amount of
from about 0.1 percent by weight to about 10 percent by weight, based on the weight
of the carrier polymer.
4. The sensor film of claim 1 wherein the pH bulTer is selected from the group
consisting of N-(2-acetamido)-2-aminoethanesulfonic acid, 2-
(carbamoylmethylamino)ethanesultbnic acid buffer, boric acid, acetic acid, sodium
hydroxide, 2>(N-Morpho!ino)ethanesulfonic acid hydrate/4-Morpholineethanesulfonic
acid, 2,2-Bis(hydroxymethyl)-2,2',2"-nitrilotriethanol/2-Bis(2-hydroxyethyl)amino-2-
{hydroxymethy])-l,3-propanediol/Bis(2-hydroxyethyl)aminotris(
hydroxymethyl)methane, N-(2-Acetamido)iminodiacetic acid/ N-
(Carbamoylmethyl)iminodiacetic acid, N-(2-Acetamido)-2-aminoethanesulfonic acid/
N-(Carbamoylmethyl)-2-aminoethane$ulfonic acid/N-(Carbamoy!methyl)taurine, 1,4-
Piperazinedietha«esulfonic acid/Piperazine-1,4-bis(2-ethanesulfonic acid)/Piperazine-
N,N'-bis(2-ethanesulfonic acid), P-Hydroxy-4-morpholinepropanesulfonic acid/3-
M:orpholino-2-hydroxypropanesulfonic acid, 1,3-
Bis[tris(hydroxymethyl)methylamino]propane, N,N-Bis(2-hydroxyethyl)-2-
aminoethanesulfonic acid/N,N-Bis(2-hydroxyethyl)taurine, 3-(NMorpholino)
propanesulfonic acid/4-Moipho!inepropanesulfonic acid, N-
[Tris(hydroxymetliyl)methyl]-2-aminoethanesulfonic acid/2-[(2-Hydroxy-1,1-
bis{hydroxymethyl)ethyl)amino3ethanesulfonic acid, 4-(2-Ilydroxyeihyl)piperazine-1-
ethanesulfonic acid/^'-(2-Hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid), 3-
(N,N-Bis[2-hydroxyethyl]araino)-2-hydroxypropanesulfonicacid/N,N-Bis(2-
hydroxyethyl)-3-amino-2-hydroxypropanesulfonic acid, 4-(NMorpholino)
biitanesMlfonicacid, 2-H.ydroxy-3-[tris(hydroxymethyl)methylamino]-lpropanesulfonTcacid/
N-[Tris(hydroxymethyl)niethy1]-3-am5no-2-
hydroxypropanesuifonic acid, 2-Amino-2-(hydroxymethyl)-l ,3-
propanediol/TrJs(hydroxymethyl)a,tTiinomet.hane/Trametamol, 4-(2-
Hydroxyethyi)pi perazine-1 -(2-hydroxypropanesulfonic acid) Bydrate, Piperazine-1,4-
bis(2-hydroxypropanesulfonicacid)dihydrate/Piperazine-N,N'-bis(2-
hydroxypropanesulfonic acid), Tris-EDTA-Acelate, 4-(2-Hydroxyethyl)-lpiperazinepropanesulfonic
acid/4-(2-Hydroxyethyi)piperazine-l -propaj^esulfonic
acid/} IEPPS/N-(2-Hydroxyethyl)piperazine-N'-(3-propa«esu1fonic acid), Nf'rris(
hydfoxymetiiyI)methynglycine, Diglycine/Glycyl-glycine, N,N-BivS{2-
hydroxyethyr)glycine, N-(2-Hydroxyethyl)piperazine-N'-(4-butanesulfonic acid), N-
[•rris(hydroxyiTietliyl)methyl3-3-aminopropanesulfonic acid/[(2-Hydroxy-l, 1-
bis(hydroxymethyl)ethyl)amino3-1 -propanesulfonic acid, 2-Amino-2-methyl-1,3-
propanediol, N-tris(Hydroxyinethyi)methy]-4-aminobutanesulfonic add, N-(l,l-
Dimethyl-2-hydroxyethyl)-3-ajnino-2-hydroxypropanesu!fonicacid, 2-
(ClyclohexyIamino)etiianes«ifonic acid, 3-(Cyc!ohexyiamino)-2-bydroxy-lpropanesulfonic
acid, 2-Amino-2-methyl-l-propanol, 3-(Cyclohexylamino)-lpropanesuifonic
acid, 4-(Cyciohexylamino)-1-butanesulfonic acid and mixtures
thereof.
5. Tlie sensor film of claim 1 wherein the pH buffer is present in an amount of
from about 1 percent by weight to about 50 percent by weight, based on the weight of
the carrier polymer,
6. The sensor flUn of claim 1 wherein the stabilizer is Arabic gum.
7. The sensor film of claim 1 wherein the stabilizer is in amount up to about 100
ppm by weight, based on the weight of the carrier polymer.
8. The sensor film of claim 1 wherein the masking agent is a salt or a cationic
surfactant.
17
9. The sensor film of claim 1 wherein the masking agent is added in an amount
up to about 2000 ppm by weight, based on the weight of the carrier polymer.
10. The sensor film of claim 1 wherein the internal reference dye is tris(2,2-
bipyridyl)dichIororuthemum(Il)hexahydrate,
11. The sensor film of claim 1 wherein the internal reference dye is present from
about 0.1 percent by weight to about 2.5 percent by weight, based on the weiglit of the
carrier polymer.
12. The sensor film of claim 1 wherein the solubilixer is fine silica.
13. The sensor film of claim! wherein the solubilizer is present in an amount of
from about 0.1 percent by weight to about 5 percent by weight, based on the weight of
the carrier polymer.
14. The sensor film of claim 1 wherein the thickness of the film is from about 0.1
to about 50 microns.
15. A method for making a sensor film comprising blending an aqueous
hydroxypropyl cellulose polymer solution with an indicator to make a first blend,
blending an aqueous hydroxypropyl cellulose polymer solution with at least one film
reactant selected from the group consisting of a pH buffer, a stabilizer, a masking
agent, an internal reference dye and a solubilizer to make a second blend, mixing the
first and second blends to make a film solution and forming a film from the film
solution.
16. The method of claim 15 wherein the indicator is a dye.
17. The method of claim 15 wherein the indicator is present in an amount of from
about 0.1 percent by weight to about 10 percent by weight, based on the weight of the
carrier polymer.
18. The method of claim 15 wherein the pH buffer is selected from the group
consisting of N-(2-acetamido)-2-aminoethanesulfonic acid, 2-
{carbamoylmethylamino)ethanesulfonic acid buffer, boric acid, acetic acid, sodium
hydroxide, 2-(N-Morphoiino)ethanesulfonic acid hydrate/4-Morpholineetlianesulfonic
acid, 2,2-Bis(hydroxymethyl)-2,2',2''-nitTilotriethano!/2-Bis(2-hydroxyethyl)aitiino-2-
(hydroxymethy})-1,3-propanediol/Bis(2-hydroxycthyI)aminotris(
bydroxymethyl)inethane, N-(2-Acetaniido)iminodiacetJc acid/ N-
(Carbamoylmethyl)iminodiacetic acid, N-(2-Acetamido)-2-aminoethanesulfonic acid/'
N-(Caibamoylmethyl)-2-aminoethanesu}fonicacid/N-(Carbamoylmethy1)taurine, 1,4-
Piperazinedietiianesulfonic add/Piperazine-1,4-bis(2-etha{iesuifonic acid)/Piperaidne-
N,N'-bis(2-etbanesulfonic acid), {$-Hydroxy-4-moipholinepropanesulfonic acid/3-
Morpholino-2-hydfoxypropanesul.fonic acid, 1,3-
Bis[tris(hydroxymethyl)methylaminoJpropane, N,M-Bis(2-hydroxyethyl)-2-
anniH>ethanesulfonicacid/N',N-Bis(2-hydroxyethyI)taurine, 3-(NMorpholino)
propanesuifonic acid/4-Morpholiiiepropanesulfonic acid, N-
[Tris(liydroxymethy l)methyl]-2-aminoethaiiesulfonic acid/2-[(2-Hydroxy-1,1 -
bis( hy droxyniethyl )ethy1 )ainino3ethanesu!fonic acid, 4-(2-Hy droxyethyl)piperazine-1 -
ethanesulfonic acid/N-(2-Hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid), 3-
{N,N'-Bis[2-hydroxyethy!]amino)-2-iiydroxypropanesulfonic acid/N,N'-Bis(2-
hydroxyethyl)-3-ainino-2-hydroxypropanesulfonic acid, 4-(NMorpholino)
butanesultbnicacid, 2-Ilydroxy-3-[t.ris(hydroxymethyl)methylaiTiino]-lpropanesuifonicacid/
N-[Tris{hydroxyniethyl)niethyl]-3-amino-2-
hydroxypropanesulfonic acid, 2-A.nuno-2-(hydroxymethyl)-1,3-
propanediol/Tris(hydroxymethyl)amijioniethane/Trometamol, 4-(2-
Hydroxyethyl)p}pera2:ine-l-(2-hydroxypropan:esulfonJc acid) Hydrate, Piperazine-1,4-
bis(2-hydroxypropanesulfonicacid)dihydrates/Piperaz:ine-N,N'-bis(2-
hydroxypropanesulfonic acid), Tris-EDTA-Acetate, 4-(2-JIy droxy ethyl)-!-
pi perazirjepropanesu!fonicacid/4-(2-Ifydroxyethyl)piperazine-l-propaiiesui tonic
acid/ HEPPS/N-(2-Hydrox>'ethyl)piperazine-N'-(3-propanesu!fonic acid), M-
[Tiis(hydroxymethy] )methyljglycine, DigJycine/Glycyl-glycine, N,N-Bis(2-
hydroxyethyl)glycine, N-(2-Hydroxyethyl)piperazine-N'-(4-butanesulfonic acid), N-
[Tris{hydroxymethyI)methyl]-3-afninopropanesultotuc acid/[(2-Hydroxy-l, 1 -
bis(hydjoxymethy1)ethyl)amino]-l-propanesulfonic acid, 2-Amino-2-methyl-L3-
propanediol, N-tris("Hydroxymethyl)methyl-4-aminobutanesulfonic acid, N-(l,l-
Dimethyl-2-hydroxyethyl)-3-amino-2-hydroxypropanesulfonicacid, 2-
(Cyclohexylamino)ethaiiesulfonicadd, 3-(Cyclohexylamino)-2-hydroxy-ipropanesulfonic
acid, 2-Amino-2-methyl-l-propanol, 3-(Cyclohexylamino)-1-
propanesulfonic acid, 4-(Cyc1ohexylamino)-l-butanesulfonic acid and mixtures
thereof.
19. The method of claim 15 wherein the pH buffer is present in an amount of from
about i percent by weight to abcnit 50 percent by weight, based on the weight of the
carrier polymer.
20. The method of claim 15 wherein the stabilizer is Arabic gum.
21. The metliod of claim 15 wherein the stabilizer is in amount up to about 100
ppm by weight, based on the weight of the canier polymer,
22. The method of claim !5 wherein the masking agent is a salt or a cationic
surfactant.
23. The method of claim 15 wherein the masking agent is added in an amount up
to about 2000 ppm by weight, based on the weight of the carrier polymer.
24. The method of claim 15 wherein the internal reference dye is tris(2,2-(Ebipyridyl)
dichlororuthenitmt(lI)hexahydrate.
25. The method of claim 15 wherein the internal reference dye is present fiom
about 0.1 percent by weight to about 2.5 percent by weight, based on the weight of the
canier polymer,
26. The method of claim 15 wherein the solubilizer is fine silica.
27. The method of claim 15 wherein the solubilizer is present in an amount of
from about 0,1 percent by weight to about 5 percent by weight, based on the weight of
the carrier polymer.
28. The method of claim 15 wherein the first blend is present in the film solution
from about 40 percent by volume to about 60 percent by volume, based on the total
volume of the film solution and the second blend is present in the film solution in an
amount of from about 60 percent by volume to about 40 percent by volume, based on
the total volume of the film solution.
29, A method for mor^itoring the concentration of \vater-so!ub!e polymers in
aqueous media including contacting the aqueous media with a sensor film, measuring
a response from an indicator and equating the response with a concentration amount,
wherein the sensor film includes a carrier polymer matrix and film reactants dispersed
within the carrier polymer matrix, the carrier polymer matrix comprising a carrier
polymer comprising hydroxypropyl cellulose polymer , the film reactants including
the indicator and at least one film reactant selected from the group consisting of a pH
buffer, a stabilizer, a masking agent, an internal reference dye and a solubilizer,
whereby the carrier polymer matrix dissolves in the aqueous media and releases the
trim reactants into the aqueous media,