SURFACE-CHARGED POLYMER COLLOIDS

1
SURFACE-CHARGED POLYMER COLLOIDS
The 2000 Korean Polymer Society Fall
Conference October 13-14, 2000 Chungnam University

• Do Ik Lee
• Emulsion Polymers RD
• The Dow Chemical Company
• Midland, Michigan 48674
• USA
• dilee_at_dow.com

2
Short Course on Polymer Colloids National
Laboratory for Nanoparticle Technology, Yonsei
University October 5-6, 2000
SURFACE-CHARGED POLYMER COLLOIDS
Do Ik Lee Emulsion Polymers RD The Dow Chemical
Company Midland, Michigan 48674 USA dilee_at_dow.com
3
Surface-Charged Polymer Colloids

• Outline of the Presentation
• Introduction
• The Critical Review of Emulsion Polymerization
  Mechanisms Homogeneous and Micellar Particle
  Nucleations
• Preparation of Surface-Charged Polymer Colloids
• Ionic Initiators
• Ionic Comonomers
• pH-Dependent Ionogenic Comonomers such as Weak
  Acids and Bases
• Hydrolysis of Esters
• Post-Reactions

4
Surface-Charged Polymer Colloids(Continued)

• Various Methods of Controlling the Placement of
  Charge or Functional Groups
• Surface-Modification by Shot Additions
• Gradient-Composition by Power-Feed or
  Computer-Aided Processes
• Core-Shell Latexes
• Inverted Core-Shell Latexes
• Cleaning and Characterization of Surface-Charged
  Polymer Colloids
• General Colloidal and Some Unique Properties
• Applications
• Summary and Conclusions

5
Introduction

• Surface-charged polymer colloids are anionic
  (negative), cationic (positive), or amphoteric
  (both negative and positive).
• Surface-charged polymer colloids are ubiquitous
  in both scientific and industrial applications.
• Surface charges impart electrostatic
  stabilization to polymer colloid particles.
• Surface-charged polymer colloids are often
  functionalized in addition to charge groups on
  the particle surfaces.
• Surface-charged polymer colloids are widely used
  for both scientific and industrial applications.

6
Introduction(Continue)

• Especially, well-defined, monodisperse
  surface-charged polymer colloids are widely used
  as
• Model colloids for basic scientific studies such
  as crystallization, self-assembly, colloidal
  stability / particle interactions, dispersion
  rheology, packing, etc.
• Calibration standards for electron microscopes,
  HDC. CHDF, etc.
• Surface-charged polymer colloids are quite
  extensively used for
• Biomedical applications such as diagnostic
  assays, immunoassays / cell separation, enzyme
  immobilization, drug delivery gene therapy, etc.
  

7
Introduction(Continued)

• Over 10 Million Metric Tons (20 Billion Pounds)
  of surface-charged polymer colloids are used in
  industrial applications
• Architectural coatings (Paints) interior and
  exterior
• Paper coatings
• Carpet backing conventional and foam backing
• Maintenance and industrial coatings
• Textile coatings
• Adhesives and Pressure-Sensitive Adhesives
• Caulks and Sealants
• Inks
• Latex foams
• Thickeners, etc.

8
Current Views on Emulsion Polymerization
Mechanisms
Reactions in Aqueous Phase I2 gt 2 I I M gt
IM IM (j-1)M gt IMj IMj IMj gt
IM2jI (Termination gt Water-Soluble
Species) IMcrit j (Surface-Active)
9
Current Views on Emulsion Polymerization
Mechanisms (Continued)
IMcrit j (Surface-Active)
Entry into Particle
Micelle Formation
Continuous Propagation
IMn
Entry into Particle
Homogeneous Nucleation
10
Current Views on Emulsion Polymerization
Mechanisms (Continued)
Reactions in the Particle
Propagation
Propagation
Termination
Transfer
M
Exit
M
11
Current Views on Emulsion Polymerization
Mechanisms (Continued)

• Surfactant-Free Emulsion Polymerization
• Mainly Homogeneous Nucleation by the
  Precipitation of Oligomeric Radicals
• Some Micellar Nucleation
• In some cases, small amounts of surfactants will
  be used for stability.

• Conventional Emulsion Polymerization
• Mainly Micellar Nucleation by Monomer-Swollen
  Micelles
• Some Homogeneous Nucleation
• Seeded Emulsion Polymerization
• Particle Nucleation Step Eliminated

12
Before Polymerization
M
-
-
M
M
M
M
I2
M
M
M
M
M
M
M
M
M
M
M
M
M
Monomer Droplets (1-10 mm)
I2
-
M
-
M
M
M
M
M
M
M
M
Monomer-Swollen Micelles (5-10 nm)
M
M
M
M
M
M
M
M
M
M
-
-
M
I2
I2
Continuous Aqueous Phase
-
Surfactant
13
Interval I Micellar Particle Nucleation
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
-
M
-
M
M
M
M
I2
M
M
M
M
M
M
M
M
M
M
M
M
M
M
Monomer Droplets (1-10 mm)
I2
-
M
-
M
M
M
M
M
M
M
Seed Particle Formation
M
M
M
M
M
M
M
M
M
M
M
M
I2
I2
-
-
M
Continuous Aqueous Phase
-
14
Interval II Constant Particle Growth Period
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
-
M
-
M
M
M
M
I2
M
M
M
M
M
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M
M
M
M
M
M
M
M
Monomer Droplet (1-10 mm)
I2
-
M
-
M
M
M
M
M
M
M
M
Seed Particles
M
M
M
M
M
M
M
M
M
M
M
I2
I2
-
-
M
Continuous Aqueous Phase
-
15
Interval III Decreasing Monomer
Concentration and Finishing Step
M
M
I2
M
M
M
M
M
M
M
M
M
M
M
M
M
M
I2
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
M
I2
M
I2
I2
M
M
M
M
M
M
M
M
M
M
M
I2
M
M
M
M
M
M
M
M
M
M
M
M
M
M
I2
I2
M
M
M
M
M
Continuous Aqueous Phase
M
16
Surface-Charged Polymer Colloids Made with Ionic
Initiators

• Anionic Initiators
• Persulfate (S2O82-) is the most widely used
  initiator in emulsion polymerization.
• S2O82- gt 2 OSO3-
  
  OSO3- M gt MOSO3- M gt M2OSO3- ..
  MjOSO3- (Surface-active) gt Adsorbed onto
  either monomer-swollen micelles or particles
• Persulfate produces surface-bound sulfate ion
  groups

17
Surface-Charged Polymer Colloids Made with Ionic
Initiators (Continued)

• In 1970, van den Hul and Vanderhoff found both
  sulfate (-OSO3-)- and hyrdoxyl (-OH)-end groups
  on persulfate-initiated particles
• OSO3- H2O gt OH HOSO3-
• Shown by Kolthoff and Miller, especially at low
  pHs
• Also, hydrolysis of sulfate-end groups results in
  hydroxyl groups.

H.J. van den Hul and J.W. Vanderhoff, Br.
Polym. J., Vol. 2, 121 (1970).
18
Schematic Representation of Persulfate-InitiatedP
olymer Colloid Particle
The total number of end-groups was found to be
close to two per polymer molecule, when hydroxyl
end-groups were added.
H.J. van den Hul and J.W. Vanderhoff, Br. Polym.
J., Vol. 2, 121 (1970).
19
Surface-Charged Polymer Colloids Made with Ionic
Initiators (Continued)

• In 1965, Matsumoto and Ochi and later in 1970,
  Kotera, Furusawa, and Takeda studied
  surfactant-free emulsion polymerizations using
  potassium persulfate as an initiator.
• Then, in 1973, Goodwin, Hearn, Ho, and Ottewill
  made systematic studies on the effect of various
  polymerization variables on particle size in
  surfactant-free emulsion polymerization using
  potassium persulfate as an initiator

20
Persulfate-Initiated Polymer Colloids Leading to
Sulfated, Sulfated/Hydroxylated, Hydroxylated,
and Carboxylated Polymer Colloids
21
Surface-Charged Polymer Colloids Made with Ionic
Initiators (Continued)

• Various anionic Initiator Systems
• S2O82- Fe2 gt Fe3 OSO3-
• OSO3- Fe3 gt Fe2 OSO3-
• S2O82- HSO3- gt SO42- OSO3- H
  SO3-
• S2O82- HOCH2SO2- gt SO42- OSO3- H
  S(CH2OH)O2-
• Also, ter-Butyl Hydroperoxide and
  Diisopropylbezene Hydroperoxide are used with
  sodium formaldehyde sulfoxylate (NaHOCH2SO2-) as
  a reducing agent at low temperatures.

22
Surface-Charged Polymer Colloids Made with Ionic
Initiators (Continued)

• Cationic Initiators
• Azo-bis(isobutyramidine hydrochloride) (AIBA
  2,2-azo-bis(2-amidinopropane) dihydrochloride
  known as V-50 from Wako Chemicals) is widely used
  as a cationic initiator

23
Surface-Charged Polymer Colloids Made with Ionic
Initiators (Continued)

• Cationic Initiators (Continued)
• In 1979, Goodwin, Ottewill, and Pelton made
  similar systematic studies on the effect of
  various polymerization variables on particle size
  in surfactant-free emulsion polymerization using
  AIBA as aninitiators
• Azo-bis(N,N-dimethylene isobutyramidine
  hydrochloride) (ADMBA) is also used.

24
Surface-Charged Polymer Colloids Made with Ionic
Comonomers

• Anionic Comonomers
• In 1976, Juang and Krieger prepared monodisperse
  sulfonated latexes by surfactant-free
  polymerization of styrene with small amounts of
  sodium styrene sulfonate (NaSS)
• Chonde and Krieger prepared sulfonated latexes by
  surfactant-free emulsion polymerization of
  styrene and sodium vinylbenzyl sulfonate (NaVBS)
  in the water-menthanol mixtures persulfate as an
  initiator.

25
Surface-Charged Polymer Colloids Made with Ionic
Comonomers (Continued)

• Anionic Comonomers (Continued)
• In 1992, Kim, Chainey, El-Aasser, and Vanderhoff
  studied the kinetics of the surfactant-free
  emulsion copolymerization of styrene and NaSS
  over a wide range of comonomer compositions
• The polymerization rate increased dramatically in
  the presence of small amounts of NaSS.
• This increas was due to the increased number of
  particles by a homogenous nucleation.
• At low NaSS concentrations, monodisperse latexes
  were obtained.
• At high NaSS concentrations, broader and bimodal
  size distributions were obtained.
• This was due to significant aqueous phase
  polymerization of NaSS.
• The occurrence of this aqueous phase side
  reaction made the preparation of highly
  sulfonated latexes impossible.

26
Surface-Charged Polymer Colloids Made with Ionic
Comonomers (Continued)

• Cationic Comonomers
• van Streun, Welt, Piet, and German studied the
  effect of the amount of 3-(methacrylamidinopropyl)
  trimethylammonium chloride (MAD) on the emulsion
  copolymerization of styrene and MAD using AIBA as
  a cationic initiator
• MAD accelerated the polymerization and decreased
  the particle size.
• Declair, Maguet, Pichot, and Mandrand prepared
  amino-functionalized by emulsion copolymerization
  of styrene and vinylbenzylamine hdrochloride
  (VBAH) using AIBA
• The use of divinylbenzene (DVB) improved
  monodispersity.

27
Surface-Charged Polymer Colloids Made with
pH-Dependent Ionogenic Comonomers

• Carboxylated Latexes
• Carboxylated latexes are the most widely used of
  all commercial latexes
• They were invented in the 1940s.
• Their benefits were recognized through the
  incorporation of MAA, AA, IA, FA, etc. onto the
  surface of latex particles.
• Since then, there has been phenomenal success in
  developing a variety of commercial carboxylated
  latexes for various applications.
• Thus, carboxylated latexes amount to more than
  90 of all the commercial latexes.
• The distribution of carboxylic groups, on the
  particle surface, in the aqueous phase, and
  inside the particle, was studied extensively in
  the 1970s and 1980s.

28
Surface-Charged Polymer Colloids Made with
pH-Dependent Ionogenic Comonomers (Continued)

• Carboxylated Latexes (Continued)
• The distribution (on surface, in medium, and
  within particle) of carboxylic groups depends on
• Type of carboxylic monomers in terms of
  hydrophilicity MMA ltAA lt IA lt FA in order of
  increasing hydrophilicity
• The degree of neutralization, that is, the degree
  of ionization
• Mode of addition Early or late addition,
  continuous addition, shot addition, etc.
• The use of more water-soluble comonomers, such as
  MMA, VCN, etc., acting as coupling agents
• Latex particle size The smaller particle size,
  the more carboxylic groups on the particle
  surface
• Ionic strength, etc.

29
Emulsion Polymerization of Nonionic Monomers with
Carboxylic Monomers
Low pHs
High pHs
AA
IA and FA
MAA
MAA, AA, IA and FA
-COO-
-COOH
-COOH
-COOH
-OOC-
-COO-
-OOC-
-OOC-
-OOC-
-COOH
-COOH
-COOH

-COO-
-OOC-
-COO-
HOOC-
-COO-
HOOC-
-COO-
HOOC-
-COO-
-OOC-
HOOC-
HOOC-
HOOC-
-COOH
-COOH
-COOH-
-OOC-
-OOC-
-OOC-
-OOC-
Increasing Hydrophilicity
Acid Distribution on the Particle Surface
Very High
High
Medium
Low
Acid Distribution inside the Particle
Very Low
Low
Medium
High and Uniform
Acid Distribution in the Aqueous Phase
High
High
Medium
Very Low
The Acid Distribution in the Carboxylated
Latexes as a Function of Acid Type and
Polymerization pH
30
Surface-Charged Polymer Colloids Made with
pH-Dependent Ionogenic Comonomers (Continued)

• A Special Class of Carboxylated Latexes
  Alkali-Swellable and Soluble Latexes (ASwLs and
  ASLs)
• In 1959, Fordyce, Dupre, and Toy invented
  alkali-soluble latexes.
• In 1966, Muroi established the factors affecting
  the alkali swelling of carboxylated latexes.
• In 1970, Verbrugge further delineated the
  properties of alkali-soluble latexes as a
  function of acid level, backbone hydrophilicity,
  Tg, molecular weight and crosslinking, etc.
• In 1981, Nishida, El-Aasser, Klein, and Vaderhoff
  showed that carboxylated latex particles had
  non-uniform distribution of carboxylic groups
  High on the surface and low in the core.

31
Brief Literature Review of the Alkali-Swelling of
Carboxylated Latex Particles
32
Emulsion Polymerization of Nonionic Monomers with
Varying Amounts of Methacrylic Acid at Low pHs
Alkali-Soluble Latex
Alkali-Swellable Latex
Conventional Carboxylated Latex
-COOH
-COOH
-COOH
-OOC-
-OOC-
-COOH
-COOH
-OOC-
-COOH
-COO-
HOOC-
-COO-
HOOC-
-COO-
HOOC-
HOOC-
HOOC-
-COOH
-COOH
HOOC-
-COOH
-OOC-
-OOC-
-OOC-
Increasing Methacrylic Acid
-COO-
-OOC-
-COO-
-COO-
-OOC-
-COO-
-COO-
-OOC-
-OOC-
-COO-
-OOC-
-COO-
-COO-
-OOC-
-COO-
-OOC-
-COO-
-OOC-
-OOC-
-COO-
-OOC-
-COO-
-COO-
-OOC-
-OOC-
-COO-
-OOC-
-OOC-
Ionized carboxylic group
Neutralization
A Special Class of Carboxylated Latexes
Alkali-Swellable and Soluble Latexes and Their
Swelling Behaviors
33
Surface-Charged Polymer Colloids Made with
pH-Dependent Ionogenic Comonomers (Continued)

• Aminated Latexes
• Amine-containing monomers such as dimethyl
  aminoethyl methacrylate (DMAEMA), 4-vinylpyridine
  (VP), etc. can be copolymerized with varous
  noionic monomers such as styrene, MMA, etc.
  either by in-situ seeded or seeded emulsion
  polymerization with either anionic, cationic or
  nonionic surfactant or by surfactant-free
  emulsion polymerization using various initiators
  such as persulfate, azo-bis(isobutyronitrile)
  (AIBN), and cationic inititiators, depending on
  the pH of polymerization.

34
Surface-Charged Polymer Colloids Made with
pH-Dependent Ionogenic Comonomers (Continued)

• Amphoteric Latexes
• Aphoteric latexes can be made by emulsion
  copolymerizations of weak acid and weak base
  monomers with various nonionic monomers either at
  low pHs or at high pHs.
• Also, amphoteric latexes can be made by emulsion
  copolymerization of various combinations of
  cationic monomers and weak acid monomers at low
  pHs and anionic monomers and weak base monomers
  at high pHs, with nonionic monomers using
  appropriate initiators and surfactants.

35
Special Emulsion Polymerization Techniques for
Controlling the Placement of Functional Monomers
in Surface-Charged Polymer Colloids

• It is highly desirable to be able to control the
  placement of functional monomers for designing
  latexes.
• It is generally advantageous to place functional
  groups on or near the particle surface for
  various reasons such as colloidal stability,
  surface functionality, post-reactions, etc.
• For this reason, great efforts have been made to
  maximize the placement of functional monomers.

36
Special Emulsion Polymerization Techniques for
Controlling the Placement of Functional Monomers
in Surface-Charged Polymer Colloids (Continued)

• Some of the Techniques Explored
• Inverted core-shell approaches by Ceska (1974),
  Lee et al. (1983), Okubo, Kanaida, and Matsumoto
  (1987), etc.
• A shot addition by Sakota and Okaya (1976)
• Power feed process to make gradient-composition
  latexes by Bassett and Hoy (1980, 1981)
• Computer-aided processes of making
  gradient-composition latexes
• Core-shell approaches

37
Special Emulsion Polymerization Techniques for
Controlling the Placement of Functional Monomers
in Surface-Charged Polymer Colloids (Continued)
Inverted Core-Shell Formation
D.I Lee and T. Ishikawa, The Formation of
Inverted Core-Shell Latexes, J. Polym. Sci.,
Polym. Chem. Ed., 21, 147 (1983).
38
Special Emulsion Polymerization Techniques for
Controlling the Placement of Functional Monomers
in Surface-Charged Polymer Colloids (Continued)
Inside Particle
Inside Particle
On Surface
On Surface
In Serum
In Serum
M. Okubo, K. Kanaida, and T. Matsumoto,
Preparation of Carboxylated Polymer Emulsion
Particles in Which carboxyl Groups are
Predominantly Localized at Surface Layer by Using
the Seeded Emulsion Polymerization Technique, J.
Appl. Polym. Sci., 33, 1511 (1987).
39
Special Emulsion Polymerization Techniques for
Controlling the Placement of Functional Monomers
in Surface-Charged Polymer Colloids (Continued)
Functional Monomer Tank
40
Special Emulsion Polymerization Techniques for
Controlling the Placement of Functional Monomers
in Surface-Charged Polymer Colloids (Continued)
Power Feed Process
Power Feed Tanks
D.R. Bassett and K.L. Hoy, Nonuniform Emulsion
Polymer Process Description and Polymer
Properties in Bassett, D.R., Hamielec, A.E.
(Eds), Emulsion Polymers and Emulsion
Polymerization, ACS Symposium Series 165,
Washington, DC, 1981, p. 371-403.
41
Surface-Charged Polymer Colloidsby Hydrolysis

• Fitch et al. (1979) prepared polymethy,
  cyclohexyl, benzyl and b-naphtyl acrylate latexes
  and polymethyl methacrylate latexes snd studied
  the kinetics of their hydrolysis to form
  carboxylated latexes.
• The acrylate latexes were treated with a mixed
  bed of strongly acid and strongly basic ion
  exchange resins.
• The hydrolysis reactions were measured by
  conductometric titration.
• Lee et al. (1992, 1996) developed hollow
  particles by hydrolysis of acrylate cores.

42
Surface-Charged Polymer Colloidsby Post-Reactions

• Lloyd et al. (1962) prepared linear and lightly
  crosslinked polyvinylbezyl chloride (PVBC)
  latexes and quaternized them with trimethylamine
  to form cationic latexes.
• Chonde, Liu, and Krieger (1980) prepared a series
  of latexes with vinylbenzyl chloride (VBC) and
  carried out nucleophilic displacement of the
  surface chloride by sulfite ions by reacting them
  with aqueous sulfite to form anionic sulfonated
  latexes.
• Wessling et al. (1980-1985) prepare cationic
  latexes by reacting VBC copolymer latexes with
  tertiary amines.
• Kawaguchi et al. (1981) prepared
  styrene-acrylamide copolymer latex and reacted it
  with hypochlorite and sodium hydroxide to form
  amino and carboxyl groups by the Hoffman reaction
  and competitive hydrolysis of amide groups,
  respectively.
• Ford et al. (1993) prepared monodisperse latexes
  with styrene (23-98), VBC (0-75), DVB (1), and
  vinylbenzyl trimethyl ammonium chloride using a
  cationic initiator and reacted them with
  trimethylamine.

43
Surface Morphology of Charged Polymer Colloid
Particles
Smooth Charged Surface
Hairy Charged Surface
44
Methods of Cleaning

• In order to remove free and adsorbed surfactants,
  water-soluble oligomers and polymers,
  electrolytes, etc., the following cleaning
  methods have been used
• Dialysis (Ottewill etal, Fitch et al., etc.)
• Mixed ion exchange (Vanderhoff et al., etc.)
• Continuous hollow dialysis / mixed ion exchange
• Serum replacement (El-Aasser et al., etc.)
• Serum replacement and ion exchange (El-Aasser et
  al., etc.)
• Ultracentrifugation (Chonde nd Krieger, etc.)

45
Characterization

• Conductometric titration
• Potentiometric titration
• Electrophoresis (z Potential Measurement)
• Turbidometric titration with a cationic
  surfactant
• Viscosity
• Particle swelling
• Etc.

46
Conductometric Titration
Conductance
Amount of NaOH Solution Added
Conductometric Titration of Persulfate-Initiated
Latex
Conductometric Titration of Persulfate-Initiated/C
arboxylated Latex
47
Potentiometric Titration
pH
Amount of NaOH Solution Added
Conductometric Titration of Persulfate-Initiated
Latex
Conductometric Titration of Persulfate-Initiated/C
arboxylated Latex
48
Electrophoresis - z Potential Measurement
U C(ez/h) z chU/e for kR lt 0.1, C 1/6p for
kR gt 100, C 1/4p
10-4 M NaCl
10-3 M NaCl
10-2 M NaCl
Zeta Potential of Amphoteric Colloids Vs. pH
49
General Colloidal Propertiesof Surface-Charged
Polymer Colloids

• Most importantly, surface-charged polymer
  colloids are electrostatically stabilized by
  surface charges.
• Their colloidal behaviors are strongly affected
  by the ionic strength of aqueous phase.
• Their stability is generally governed by the
  Schulz-Hardy Rule The effect of counter-ion
  valency.
• Industrially, surface-charged polymer colloid
  particles are often combined with nonionic steric
  stabilizers to achieve electrosteric (both
  electrostatic/steric) stabilization.
• Industrially, they are often modified with a
  variety of functional groups.

50
Some Unique Properties of Surface-Charged Polymer
Colloids - Iridescence
Monodisperse Polyvinyl Toluene Latex R.M. Fitch,
Polymer Colloids A Comprehensive Introduction,
Academic Press, New York, 1997.
51
Some Unique Properties of Surface-Charged Polymer
Colloids - Order-Disorder Behaviors
Monodisperse Polymethy Acrylate Latex Showing
Three Phases at Equilibrium R.M. Fitch, Polymer
Colloids A Comprehensive Introduction, Academic
Press, New York, 1997.
52
Some Unique Properties of Surface-Charged Polymer
Colloids - Ordered Packing
Ordered Packing of Monodisperse Polystyrene Latex
Particles An Introduction to Polymer Colloids,
Ed. F. Candau and R.H. Ottewill, Kluwer Academic
Publishers, 1990.
53
Some Unique Properties of Surface-Charged Polymer
Colloids - Cell Separation
Carbodiimide Method for Antibody Conjugation
(Fitch et al.)
Carboxylated Latex Particle
Antibody
Latex Particle-Antibody Conjugate
Latex Particle with Antibody Molecules on Surface
54
Some Unique Properties of Surface-Charged Polymer
Colloids- Immunoassay
Antigen-Coated Latex Particle
Antigen-Coated Latex Particle
Agglutinated Latex Particle
Antibody
Latex Agglutination
55
Applications of Surface-ChargedPolymer Colloids

• In addition to their use for various scientific
  studies, surface-charged polymer colloids are
  widely used in industrial applications such as
• Architectural coatings (Paints) interior and
  exterior
• Paper coatings
• Carpet backing conventional and foam backing
• Maintenance and industrial coatings
• Textile coatings
• Adhesives and Pressure-Sensitive Adhesives
• Caulks and Sealants
• Inks
• Latex foams
• Thickeners, etc.

56
Summary and Conclusions

• Surface-charged polymer colloids can be prepared
  to be anionic, cationic or amphoteric using ionic
  initiators, ionic comonomers, pH-dependent weak
  acid and base monomers, hydrolysis or
  post-reactions.
• The placement of charge groups can be effectively
  controlled by inverted core-shell, shot addition,
  power feed, computer-aided feed or core-shell
  approaches.
• Smooth and hairy charged surfaces are two extreme
  particle surface morphologies.
• Surface-charged polymer colloids can be cleaned
  by dialysis, ion exchange, serum replacement or
  ultracentrifugation, and then subsequently
  characterized by conductometric and
  potentiometric titrations, electrophoresis or
  turbidometry.

57
Summary and Conclusions (Continued)

• Particle surface charges provide electrostatic
  stabilization.
• The colloidal properties of surface-charged
  polymer colloids are highly affected by the
  amount and valency of counter ions.
• Additionally, monodisperse surface-charged
  particles have unique properties such as
  iridescence, order-disorder behaviors, ordered
  packing, etc.
• Surface-charged polymer colloids are widely used
  in both scientific studies and industrial
  applications.
• The control of surface-charges on polymer colloid
  particles is one of the most important pillars
• for latex technologies.

58
References

• For Emulsion Polymerization Mechanisms
• Gilbert R G, Emulsion Polymerization A
  Mechanistic Approach, Academic Press, London
  1995
• For Persulfate-Initiated Latexes
• van den Hul H J, Vanderhoff J W, British Polym.
  J., 2, 121 (1970).
• van den Hul H J, Vanderhoff J W, in Fitch R M
  (Ed), Polymer Colloids, Plenum Press, New York
  1971, p 1
• Kotera A, Furusawa K, Takeda Y, Kolloid-Z. u. Z.
  Polymere, 239, 677 (1970)
• Matsumoto T, and Ochi A, Kobunshi-Kagaku (Tokyo),
  22, 481 (1965)
• Goodwin J W, Hearn J, Ho C C, Ottewill R H, Br.
  Polym. J., 5, 347 (1973).
• Goodwin J W, Hearn J, Ho C C, Ottewill R H,
  Colloid Polym. Sci., 252, 464 (1974).
• For Cationic Initiator-driven Latexes
• Goodwin J W, Ottewill R H, Pelton R H, Colloid
  Polym. Sci., 257, 61 (1979).
• For Surfactant-Free Emulsion Polymerization
• Matsumoto T, and Ochi A, Kobunshi-Kagaku (Tokyo),
  22, 481 9 1965).
• Kotera A, Furusawa K, Takeda Y, Kolloid-Z. u. Z.
  Polymere, 239, 677 (1970).
• For Acid Distributions in Latexes
• Greene B W, J. Colloid Interface Sci., 43, 449
  (1973).
• Greene B W, J. Colloid Interface Sci., 43, 462
  (1973).
• Hen J, J. Colloid Interface Sci., 49, 425 (1974).
• Ceska GW, J. Appl. Polym. Sci., 18, 427 (1974).

59
References (Continued)

• For Controlled Placement of Functional Groups
• Ceska G W, J. Appl. Polym. Sci., 18, 2493 91974).
• Okubo M, Kanaida K, Matsumoto T, J. Appl. Polym.
  Sci., 33, 1511 (1987).
• Lee D I, Ishikawa T, J. Polym. Sci., Polym. Chem.
  Ed., 21, 147 (1983).
• Muroi S, Hoshimoto H, Hosoi K, J. Polym. Sci.,
  Polym. Chem. Ed., 22, 1365 (1984).
• Cho I, Lee K W, J. Appl. Polym. Sci., 30, 1903
  (1985).
• Lee D I, Kawamura T, Stevens E F, in El-Aasser M
  S, Fitch R M (Eds), Future Directions in Polymer
  Colloids, NATO ASI Series, Series E Applied
  Sciences - No. 138, Martinus Nijhoff, Dordrecht
  1987, p 47
• Hoy K L, J. Coat. Technol., 51 (651), 27 (1979).
• Bassett D R, Hoy K L, in Bassett D R, Hamielec A
  E (Eds), Emulsion Polymers and Emulsion
  Polymerization, ACS Symposium Series 165,
  Washington DC 1981, p 371
• For Alkali-Swelling of Carboxylated Latexes
• Fordyce D B, Dupre D, Toy W, Ind. Eng. Chem., 51,
  115 (1959).
• 70 Fordyce D B, Dupre D, Toy W, Off. Dig. Fed.
  Soc. Paint Technol., 31, 284 (1959).
• 71 Muroi S, J. Appl. Polym. Sci., 10, 713 (1966).
• 72 Muroi S, Hosoi K, Ishikawa T, J. Appl. Polym.
  Sci., 11, 163 (1967).
• 73 Verbrugge C J, J. Appl. Polym. Sci., 14, 897
  (1970).
• 74 Verbrugge C J, J. Appl. Polym. Sci., 14, 911
  (1970).
• 75 Nishida S, El-Aasser M S, Klein A, Vanderhoff
  J W, in Bassett D R, Hamielec A E (Eds), Emulsion
  Polymers and Emulsion Polymerization, ACS
  Symposium Series 165, ACS, Washington, DC 1981, p
  29.

60
References (Continued)

• For Hydrolysis and Post-reactions
• Lloyd W G, Vitkuske J F, J. Appl. Polym. Sci.,
  6(24), S56 (1962).
• Lloyd W G, Durocher T E, J. Polym. Sci., 7, 2025
  (1963).
• Lloyd W G, Durocher T E, J. Polym. Sci., 8, 953
  (1964).
• Chonde Y, Liu L-J, Krieger I M, J. Applied Polym.
  Sci., 25, 2407 (1980).
• Wessling R A, Yats L D, Meyer V E, Organic
  Coatings Plast. Chem., 42, 156 (1980).
• Wessling R A, in Poehlein G W, Ottewill R H,
  Goodwin J W. (Eds), Science and Technology of
  Polymer Colloids, Vol. II, Martinus Nijhoff Pub,
  The Hague, The Netherlands 1983, p 393
• Wessling R A, Yats L D, Makromol. Chem., Suppl.,
  10/11, 319 (1985).
• Kawaguchi H, Hoshino H, Ohtsuka Y, J. Appl.
  Polym. Sci., 26, 2015 (1981).
• For Latex Cleaning
• Ottewill R H, Shaw J N, Kolloid-Z. u. Z.
  Polymere, 218, 34 (1967).
• Shaw J N, Marshall M C, J. Polym. Sci., Part A1,
  6, 449 (1968).
• van den Hul H J, Vanderhoff J W, J. Colloid
  Interface Sci. 1968, 28, 336 (1968).
• Vanderhoff J W, van den Hul H J, Tausk R J M,
  Overbeek J Th G, in Goldfinger G (Ed), Clean
  Surfaces Their Preparation and Characterization
  for Interfacial Studies, Marcel Dekker, New York
  1970, p 15
• El-Aasser M S, in Poehlein G W, Ottewill R H,
  Goodwin J W. (Eds), Science and Technology of
  Polymer Colloids, Vol. II, Martinus Nijhoff Pub,
  The Hague, The Netherlands 1983, p 422
• Ahmed S M, El-Aasser M S, Pauli G H, Poehlein G
  W, Vanderhoff, J W, J. Colloid Interface Sci.,
  73, 388 (1980).
• Labib M E, Robertson A A, J. Colloid Interface
  Sci., 67, 543 (1978).
• Labib M E, Robertson A A, J. Colloid Interface
  Sci., 77, 151 (1980).
• Wilkinson M C, Hearn J, Cope P, Chaney M, British
  Polymer J., 13, 82 (1981).

61
References (Continued)

• For Characterization
• van den Hul H J, Vanderhoff J W, J. Colloid
  Interface Sci., 28, 336 (1968).
• van den Hul H J, Vanderhoff J W, British Polym.
  J., 2, 121 (1970).
• Vanderhoff J W, van den Hul H J, Tausk R J M,
  Overbeek J Th G, in Goldfinger G (Ed), Clean
  Surfaces Their Preparation and Characterization
  for Interfacial Studies, Marcel Dekker, New York
  1970, p 15
• van den Hul H J, Vanderhoff J W, in Fitch R M
  (Ed), Polymer Colloids, Plenum Press, New York
  1971, p 1
• Ottewill R H, Shaw J N, Kolloid-Z. u. Z.
  Polymere, 218, 34 (1967).
• Kotera A, Furusawa K, Takeda Y, Kolloid-Z. u. Z.
  Polymere, 239, 677 (1970).
• Saxton R, Daniel Jr K H, J. Appl. Polym. Sci., 8,
  325 (1964).
• Fitch R M, Polymer Colloids A Comprehensive
  Introduction, Academic Press, New York 1997, p
  148-149
• Krieger I M, Eguiluz M, Trans. Soc. Rheol., 20,
  29 (1976).
• Buscall R, Goodwin J W, Hawkins M W, Ottewill R
  H, J. Chem. Soc. Faraday Trans. I, 78, 2873
  (1982).
• Bergenholtz J, Willenbacher N, Wagner N J,
  Morrison B, van den Ende D, Mellema J J, Colloid
  Interface Sci., 202, 430 (1998).
• Hoy K L, J. Coat. Technol., 51 (651), 27 (1979).
• Bassett D R, Hoy K L, in Bassett D R, Hamielec A
  E (Eds), Emulsion Polymers and Emulsion
  Polymerization, ACS Symposium Series 165,
  Washington DC 1981, p 371
• Ottewill R H, in El-Aasser M S, R. Fitch M (Eds),
  Future Directions in Polymer Colloids, NATO ASI
  Series, Series E Applied Sciences - No. 138,
  Martinus Nijhoff, Dordrecht 1987, p 253
• Ottewill R H, in Candau F, Ottewill R H (Ed),
  Scientific Methods for the Study of Polymer
  Colloids and Their Applications, NATO ASI Series,
  Series C 303, Kluwer Academic, Dordrecht 1990, p
  349
• Fitch R M, Polymer Colloids A Comprehensive
  Introduction, Academic Press, New York 1997, p
  120-128
• Fitch R M, Su L-S, Tsaur S-L, in Candau F,
  Ottewill R H (Ed), Scientific Methods for the
  Study of Polymer Colloids and Their Applications,
  NATO ASI Series, Series C 303, Kluwer Academic,
  Dordrecht 1990, p 373
• Banthia A K, Mandal B M, Palit S R, J. Polym.
  Sci., Polym. Chem. Ed., 15, 945 (1977).