1. SURFACE-CHARGED POLYMER COLLOIDS Do Ik Lee Emulsion Polymers R&D The Dow Chemical Company Midland, Michigan 48674 USA dilee@dow.com The 2000 Korean Polymer Society Fall Conference October 13-14, 2000 Chungnam University

2. SURFACE-CHARGED POLYMER COLLOIDS Do Ik Lee Emulsion Polymers R&D The Dow Chemical Company Midland, Michigan 48674 USA dilee@dow.com Short Course on Polymer Colloids National Laboratory for Nanoparticle Technology, Yonsei University October 5-6, 2000

3. Surface-Charged Polymer Colloids Outline of the Presentation F Introduction F The Critical Review of Emulsion Polymerization Mechanisms: Homogeneous and Micellar Particle Nucleations F 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. F 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 F Cleaning and Characterization of Surface-Charged Polymer Colloids F General Colloidal and Some Unique Properties F Applications F Summary and Conclusions Surface-Charged Polymer Colloids (Continued)

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

6. F 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. F 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. Introduction (Continue)

7. F 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. Introduction (Continued)

8. Current Views on Emulsion Polymerization Mechanisms Reactions in Aqueous Phase I 2 > 2 I I + M > IM IM + (j-1)M > IM j IM j + IM j > IM 2j I (Termination > Water-Soluble Species) IM crit j (Surface-Active) Entry into Particle Micelle Formation Continuous Propagation

9. Current Views on Emulsion Polymerization Mechanisms (Continued) Entry into Particle Micelle Formation Continuous Propagation IM crit j (Surface-Active) IM n Entry into Particle Homogeneous Nucleation

10. Radical Entry from the Aqueous Phase Reactions in the Particle Propagation Termination Transfer + M Exit M Propagation Current Views on Emulsion Polymerization Mechanisms (Continued)

11. F Surfactant-Free Emulsion Polymerization –Mainly Homogeneous Nucleation by the Precipitation of Oligomeric Radicals –Some Micellar Nucleation F In some cases, small amounts of surfactants will be used for stability. F Conventional Emulsion Polymerization –Mainly Micellar Nucleation by Monomer-Swollen Micelles –Some Homogeneous Nucleation F Seeded Emulsion Polymerization –Particle Nucleation Step Eliminated Current Views on Emulsion Polymerization Mechanisms (Continued)

12. Monomer-Swollen Micelles (5-10 nm) M M M M Monomer Droplets (1-10  m) M M M M M M M M M MM M M M M MM M M M M M M M M MM M M M M I2I2 I2I2 I2I2 I2I2 M Continuous Aqueous Phase Before Polymerization M         M M M M M M M M M M M M M M M M         M M M M M M M M M M M M M M M M         M M M M M M M M M M M M M M M M         M  : Surfactant

13. M M M M Monomer Droplets (1-10  m) M M M M M M M M M MM M M M M MM M M M M M M M M MM M M M M I2I2 I2I2 I2I2 I2I2 M Continuous Aqueous Phase 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 M M M M M M M M M M M M M M         Seed Particle Formation M M M M M M M M M M M M M M M M M        

14. M M M M Monomer Droplet (1-10  m) M M M M M M M M M MM M M M M MM M M M M M M M M MM M M M M I2I2 I2I2 I2I2 I2I2 M Continuous Aqueous Phase Interval II: Constant Particle Growth Period M         M M M M M M M M M M M M M M M M M         Seed Particles M  M M M M M M M M M M M M M M M M        M M M M M M M M M M M M M M M M        

15. M M M M M I2I2 I2I2 I2I2 I2I2 Continuous Aqueous Phase Interval III: Decreasing Monomer Concentration and Finishing Step M M M M M M M M M M M M M M         M M M I2I2 I2I2 I2I2 M M M M M M M M M M M M         M M M M M M M M M M M         M M M M M M M M M M M         M M M M M M M M M M M         I2I2

16. F Anionic Initiators –Persulfate (S 2 O 8 2- ) is the most widely used initiator in emulsion polymerization. –S 2 O 8 2- > 2 OSO 3 -OSO 3 - + M > MOSO 3 - + M > M 2 OSO 3 - ……..M j OSO 3 - (Surface-active) > Adsorbed onto either monomer-swollen micelles or particles –Persulfate produces surface-bound sulfate ion groups: Surface-Charged Polymer Colloids Made with Ionic Initiators M j OSO 3 -

17. F In 1970, van den Hul and Vanderhoff* found both sulfate (- OSO 3 - ) - and hyrdoxyl (-OH)-end groups on persulfate-initiated particles: –OSO 3 - + H 2 O >OH + HOSO 3 - –Shown by Kolthoff and Miller, especially at low pH’s –Also, hydrolysis of sulfate-end groups results in hydroxyl groups. Surface-Charged Polymer Colloids Made with Ionic Initiators (Continued) * H.J. van den Hul and J.W. Vanderhoff, Br. Polym. J., Vol. 2, 121 (1970).

18. Schematic Representation of Persulfate-Initiated Polymer Colloid Particle H.J. van den Hul and J.W. Vanderhoff, Br. Polym. J., Vol. 2, 121 (1970). The total number of end- groups was found to be close to two per polymer molecule, when hydroxyl end-groups were added.

19. F In 1965, Matsumoto and Ochi and later in 1970, Kotera, Furusawa, and Takeda studied surfactant-free emulsion polymerizations using potassium persulfate as an initiator. F 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: Surface-Charged Polymer Colloids Made with Ionic Initiators (Continued)

20. Persulfate-Initiated Polymer Colloids Leading to Sulfated, Sulfated/Hydroxylated, Hydroxylated, and Carboxylated Polymer Colloids Persulfate-Initiated Emulsion Polymerization - OSO 3 - - OH HO - - O 3 SO - HO - - OSO 3 - - O 3 SO - - OH HO - - COO - - OOC - High pHsLow pHs Hydrolysis/OxidationHydrolysis Hydroxylated Latex Carboxylated Latex Sulfated/Hydroxylated LatexSulfated Latex Hydrolysis

21. F Various anionic Initiator Systems –S 2 O 8 2- + Fe 2+ > Fe 3+ +OSO 3 - –OSO 3 - + Fe 3+ > Fe 2+ +OSO 3 - –S 2 O 8 2- + HSO 3 - > SO 4 2- + OSO 3 - + H + +SO 3 - –S 2 O 8 2- + HOCH 2 SO 2 - > SO 4 2- + OSO 3 - + H + +S(CH 2 OH)O 2 - –Also, ter-Butyl Hydroperoxide and Diisopropylbezene Hydroperoxide are used with sodium formaldehyde sulfoxylate (NaHOCH 2 SO 2 - ) as a reducing agent at low temperatures. Surface-Charged Polymer Colloids Made with Ionic Initiators (Continued)

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

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

24. F 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. Surface-Charged Polymer Colloids Made with Ionic Comonomers

25. F 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: u The polymerization rate increased dramatically in the presence of small amounts of NaSS. u This increas was due to the increased number of particles by a homogenous nucleation. u At low NaSS concentrations, monodisperse latexes were obtained. u At high NaSS concentrations, broader and bimodal size distributions were obtained. u This was due to significant aqueous phase polymerization of NaSS. u The occurrence of this aqueous phase side reaction made the preparation of highly sulfonated latexes impossible. Surface-Charged Polymer Colloids Made with Ionic Comonomers (Continued)

26. F 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: u 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: u The use of divinylbenzene (DVB) improved monodispersity. Surface-Charged Polymer Colloids Made with Ionic Comonomers (Continued)

27. F Carboxylated Latexes –Carboxylated latexes are the most widely used of all commercial latexes: u They were invented in the 1940s. u Their benefits were recognized through the incorporation of MAA, AA, IA, FA, etc. onto the surface of latex particles. u Since then, there has been phenomenal success in developing a variety of commercial carboxylated latexes for various applications. u Thus, carboxylated latexes amount to more than 90% of all the commercial latexes. u 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. Surface-Charged Polymer Colloids Made with pH-Dependent Ionogenic Comonomers

28. F Carboxylated Latexes (Continued) –The distribution (on surface, in medium, and within particle) of carboxylic groups depends on: u Type of carboxylic monomers in terms of hydrophilicity: MMA <AA < IA < FA in order of increasing hydrophilicity u The degree of neutralization, that is, the degree of ionization u Mode of addition: Early or late addition, continuous addition, shot addition, etc. u The use of more water-soluble comonomers, such as MMA, VCN, etc., acting as coupling agents u Latex particle size: The smaller particle size, the more carboxylic groups on the particle surface u Ionic strength, etc. Surface-Charged Polymer Colloids Made with pH-Dependent Ionogenic Comonomers (Continued)

29. The Acid Distribution in the Carboxylated Latexes as a Function of Acid Type and Polymerization pH Emulsion Polymerization of Nonionic Monomers with Carboxylic Monomers - COOH - COO - - COOH - OOC - HOOC - - OOC - HOOC - High pHs Low pHs - COOH - COO - - COOH - OOC - HOOC - - OOC - HOOC - - COOH - COO - - COOH- - COOH - OOC - HOOC - - OOC - HOOC - - COO - - OOC - AAIA and FA MAAMAA, AA, IA and FA Increasing Hydrophilicity Acid Distribution inside the Particle Very LowLow Medium High and Uniform Acid Distribution in the Aqueous Phase High Medium Very Low Acid Distribution on the Particle Surface Very HighHigh Medium Low

30. F A Special Class of Carboxylated Latexes: Alkali- Swellable and Soluble Latexes (ASwL’s and ASL’s) –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. Surface-Charged Polymer Colloids Made with pH-Dependent Ionogenic Comonomers (Continued)

31. Brief Literature Review of the Alkali- Swelling of Carboxylated Latex Particles COOH HOOC COOH HOOC COOH COO - Na + Na + - OOC COO - Na + or NH 4 + COO - Na + Na + - OOC COO - Na + H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O Add Base Neutralize The Alkali-Swelling of Carboxylated Latex Particles Depends on: Acid Type and Content (1-3) Polymer Backbone Hydrophilicity (2, 3) Dissolution Temperature (2) / Polymer Tg (2-3) Molecular Weight (2) / Crosslinking Degree of Neutralization, pH Etc. References: 1. D. B. Fordyce, J. Dupre, and W. Toy, Official Digest, 31, 284 (1959). 2. S. Muroi, J. Appl. Polym. Sci., 11, 1963 (1967). 3. C. J. Verbrugge, J. Appl. Polym. Sci., 14, 897 (1970).

32. A Special Class of Carboxylated Latexes; Alkali-Swellable and Soluble Latexes and Their Swelling Behaviors Emulsion Polymerization of Nonionic Monomers with Varying Amounts of Methacrylic Acid at Low pHs - COOH - COO - - COOH - OOC - HOOC - - OOC - HOOC - - COOH - COO - - COOH - OOC - HOOC - - OOC - HOOC - - COOH - COO - - COOH - OOC - HOOC - - OOC - HOOC - Increasing Methacrylic Acid - COO - - OOC - - COO - - OOC - Neutralization Unionized carboxylic group Ionized carboxylic group Alkali-Soluble LatexAlkali-Swellable LatexConventional Carboxylated Latex - COO - - OOC - - COO -

33. F 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. Surface-Charged Polymer Colloids Made with pH-Dependent Ionogenic Comonomers (Continued)

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

35. F It is highly desirable to be able to control the placement of functional monomers for designing latexes. F 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. F For this reason, great efforts have been made to maximize the placement of functional monomers. Special Emulsion Polymerization Techniques for Controlling the Placement of Functional Monomers in Surface-Charged Polymer Colloids

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

37. 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) 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). Inside Particle On Surface In Serum Inside Particle On Surface In Serum

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 Tanks Power Feed Process 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.  Fitch et al. (1979) prepared polymethy, cyclohexyl, benzyl and  -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. Surface-Charged Polymer Colloids by Hydrolysis

42. F Lloyd et al. (1962) prepared linear and lightly crosslinked polyvinylbezyl chloride (PVBC) latexes and quaternized them with trimethylamine to form cationic latexes. F 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. F Wessling et al. (1980-1985) prepare cationic latexes by reacting VBC copolymer latexes with tertiary amines. F 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. F 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. Surface-Charged Polymer Colloids by Post-Reactions

43. Surface Morphology of Charged Polymer Colloid Particles - Anionic or Cationic Charge Group Smooth Charged Surface Hairy Charged Surface

44. Methods of Cleaning F 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. F Conductometric titration F Potentiometric titration  Electrophoresis (  Potential Measurement) F Turbidometric titration with a cationic surfactant F Viscosity F Particle swelling F Etc. Characterization

46. Conductometric Titration Conductometric Titration of Persulfate-Initiated Latex Amount of NaOH Solution Added Conductance Amount of NaOH Solution Added Conductometric Titration of Persulfate-Initiated/Carboxylated Latex

47. Potentiometric Titration Conductometric Titration of Persulfate-Initiated Latex Conductometric Titration of Persulfate-Initiated/Carboxylated Latex Amount of NaOH Solution Added pH Amount of NaOH Solution Added

48. Electrophoresis -  Potential Measurement 06428 pH Zeta  Potential, mv Zeta Potential of Amphoteric Colloids Vs. pH U = C(  )  c  U  for  R  C  for  R  C  10 -4 M NaCl 10 -3 M NaCl 10 -2 M NaCl

49. General Colloidal Properties of Surface-Charged Polymer Colloids F Most importantly, surface-charged polymer colloids are electrostatically stabilized by surface charges. F Their colloidal behaviors are strongly affected by the ionic strength of aqueous phase. F Their stability is generally governed by the Schulz-Hardy Rule: The effect of counter-ion valency. F Industrially, surface-charged polymer colloid particles are often combined with nonionic steric stabilizers to achieve electrosteric (both electrostatic/steric) stabilization. F 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 Latex Particle-Antibody Conjugate Antibody Carboxylated Latex Particle Carbodiimide Method for Antibody Conjugation (Fitch et al.) Latex Particle with Antibody Molecules on Surface

54. Some Unique Properties of Surface-Charged Polymer Colloids- Immunoassay Antigen-Coated Latex Particle Antibody Antigen-Coated Latex Particle Agglutinated Latex Particle Latex Agglutination

55. F 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. Applications of Surface-Charged Polymer Colloids

56. Summary and Conclusions F 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. F The placement of charge groups can be effectively controlled by inverted core-shell, shot addition, power feed, computer-aided feed or core-shell approaches. F Smooth and hairy charged surfaces are two extreme particle surface morphologies. F 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. F Particle surface charges provide electrostatic stabilization. F The colloidal properties of surface-charged polymer colloids are highly affected by the amount and valency of counter ions. F Additionally, monodisperse surface-charged particles have unique properties such as iridescence, order-disorder behaviors, ordered packing, etc. F 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. Summary and Conclusions (Continued)

58. References F For Emulsion Polymerization Mechanisms: –Gilbert R G, “Emulsion Polymerization: A Mechanistic Approach”, Academic Press, London 1995 F 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). F For Cationic Initiator-driven Latexes: –Goodwin J W, Ottewill R H, Pelton R H, Colloid Polym. Sci., 257, 61 (1979). F 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). F 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). –Ceska G W, J. Appl. Polym. Sci., 18, 2493 (1974). –Vijayendran B R, J. Appl. Polym. Sci., 23, 893 (1979).

59. References (Continued) F 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 F For Alkali-Swelling of Carboxylated Latexes: –Fordyce D B, Dupre D, Toy W, Ind. Eng. Chem., 51, 115 (1959). –70Fordyce D B, Dupre D, Toy W, Off. Dig. Fed. Soc. Paint Technol., 31, 284 (1959). –71Muroi S, J. Appl. Polym. Sci., 10, 713 (1966). –72Muroi S, Hosoi K, Ishikawa T, J. Appl. Polym. Sci., 11, 163 (1967). –73Verbrugge C J, J. Appl. Polym. Sci., 14, 897 (1970). –74Verbrugge C J, J. Appl. Polym. Sci., 14, 911 (1970). –75Nishida 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) F 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). F 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). –Chonde Y, Krieger I M, J. Colloid Interface Sci., 77, 138 (1980). –Fitch R M, Polymer Colloids: A Comprehensive Introduction, Academic Press, New York 1997, p 132-133

61. References (Continued) F 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).