ACS SYMPOSIUM SERIES 755 Specialty Monomers and Polymers Synthesis, Properties, and Applications 1 0 0 w 5.f 5 7 0 0- 0 0 2 bk- Kathleen O. Havelka, EDITOR 1/ 2 0 The Lubrizol Corporation 1 0. 1 http://pubs.acs.org March 27, 2000 | doi: ChUarnlievse rLsi. tyM ocfC Soourtmheicrnk ,M EiDsIsTisOsiRp pi 2012 | Date: ember 7, blication Sept Pu American Chemical Society, Washington, DC In Specialty Monomers and Polymers; Havelka, K., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2000. Library of Congress Cataloging-in-Publication Data Specialty monomers and polymers: synthesis, properties, and applications / Kathleen O. Havelka, editor, Charles L McCormick, editor. p. cm — (ACS symposium series, ISSN 0097-6156; 755) Includes bibliographical references and index. ISBN 0-8412-3637-2 1. Polymers—Congresses. 2. Monomers—Congresses. 1 0 0 w I. Havelka, Kathleen O., 1964- . II. McCormick, Charles L., 1946- . III. Series. 5.f 5 7 0 0- QD380 .S865 2000 0 20 547'.7—dc21 99-58314 k- b 1/ 2 0 1 0. 2012 | http://pubs.acs.org Date: March 27, 2000 | doi: 1 DACpCfoalooirlgs p pTtIeRryynhi rribifegiisougg hprpthhmteaasttdp i a©AdR etbi rc eoty 2tousn 0eis O st0reShv xd0aceef lio AdileConrn.md w octR hpeeUeeisrydsp—inrc rpfiiavoogPuneghrbe r rtCrilsa mniiCphcttyahaeelen rtmiiPncaeoir arncnacelcanso eumlscp s Seyeeoo ei Cfncot Psiegne an tltbhpytyeeee, ry rp,m o rfInooinndvrci i .mPdt,h re2uiadn2mt t2 tep h rreRae Lrqtom uiasbiie rtrpewtaeemrrody-eo c nMbdhtya sDap tStoreeierfvric aAetfli,esom D,en eA saro niNfc1v aS0$enI72r s Z0N,o. 30Mar9 t0iA1.o 40p n808lau-1 9lso 94 Sf$2 t10t3ah9n.,5e 8dU 04Ua Sr.p .dASe .r. ember 7, blication RDSteirrpeeeuctbt, l tNihc.eaWstieo., n aW nodar sorhethipnergor tdopunecr,tm DioiCnss 2ifoo0nr0 s3s 6arel.e q uoefs ptsa gtoe sA iCn Sth Ciso bpoyorikg hist pOefrfmiciet,t ePdu obnlilcya tuionndes rD liivciesniosen f, r1o1m55 A 1C6tSh. Sept Pu The citation of trade names and/or names of manufacturers in this publication is not to be construed as an endorsement or as approval by ACS of the commercial products or services referenced herein; nor should the mere reference herein to any drawing, specification, chemical process, or other data be regarded as a license or as a conveyance of any right or permission to the holder, reader, or any other person or corporation, to manufacture, reproduce, use, or sell any patented invention or copyrighted work that may in any way be related thereto. Registered names, trademarks, etc., used in this publication, even without specific indication thereof, are not to be considered unprotected by law. PRINTED IN THE UNITED STATES OF AMERICA In Specialty Monomers and Polymers; Havelka, K., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2000. Foreword 1HE ACS SYMPOSIUM SERIES was first published in 1974 to provide a mechanism for publishing symposia quickly in book form. The pur pose of the series is to publish timely, comprehensive books devel oped from ACS sponsored symposia based on current scientific re search. Occasionally, books are developed from symposia sponsored by other organizations when the topic is of keen interest to the chem istry audience. 1 Before agreeing to publish a book, the proposed table of contents 0 w0 is reviewed for appropriate and comprehensive coverage and for in 5.f terest to the audience. Some papers may be excluded in order to better 5 7 0 focus the book; others may be added to provide comprehensiveness. 0- 00 When appropriate, overview or introductory chapters are added. 2 k- Drafts of chapters are peer-reviewed prior to final acceptance or re b 21/ jection, and manuscripts are prepared in camera-ready format. 0 0.1 As a rule, only original research papers and original review pa 1 acs.org 000 | doi: poeurssl ya preu bilnischluedd epda piner sth aer ev noolut macecse. pVteedr.b atim reproductions of previ http://pubs.March 27, 2 ACS BOOKS DEPARTMENT 2012 | Date: ember 7, blication Sept Pu In Specialty Monomers and Polymers; Havelka, K., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2000. Preface This book is a compendium of refereed papers based on invited talks presented at the American Chemical Society (ACS) Symposium on Specialty Monomers and Their Polymers. Specialty monomers are inherently different from commodity monomers, and it is these differences that result in new and important polymer properties. The most versatile feature of specialty monomers and polymers is their built-in functionality. This functionality offers significant opportunity to customize the design of polymers to meet specific performance, physical, and chemical properties. These properties are needed for many of today's hi-tech applications and cannot be easily obtained with more common commodity monomers and polymers. Specialty polymers have emerged as an important class of materials because they offer flexibility, both at the molecular and bulk levels, to optimize physical and chemical properties 1 for medical and industrial applications. Because the structure of synthetic specialty polymers 0 0 can be easily controlled and measured, they are frequently used to model the more complex pr 5. natural polymers. Using well defined model compounds facilitates significant advancements 5 7 in our understanding of fundamental properties. Increased understanding of materials issues 0 0- will expedite the development of "smart polymers" that have unique, tunable, and responsive 0 0 2 properties. Developing "smart polymers" requires a highly multidisciplinary approach, the k- b progress of which depends on active collaboration from diverse groups, including chemists, 1/ 2 biologists, physicians, physicists, material scientists, and engineers. 0 1 0. Considering that interest in specialty polymers and "smart polymers" is growing 1 g doi: vwoolurlmdwe itdhea ta cnodv ecrosn ismidpeorirntagn ti tcsu mrreunltti ddiesvceilpolpinmaernyt ns aitnur teh,i sa fineeledd. Texhiisst sb ofookr ias cinotmenpdreedhe tnos ivfiell http://pubs.acs.orMarch 27, 2000 | rttsohheuff aecetithhrr e etnrah ec iasvserpo t eb ibdcioont oiob vtkkyoe p fwpaoircirrolesl v r aerbisads.enei nagTogricnfh bhgegre robrferaosaod ootm k fcv oviapsvalou reclireyeoa mdmgt oeebp rarro ecesfhksy eergnenartcoshriceuevhnsneietds rsw,is n. t o eosrn ckmtoe bpraiyetne, glrcei aoatldhvsi,een r tgiaon r igean aptae pnarldnsica patwirtooieonvlnlai dsla .i ssnc gWiae tnhevt eaiisnl usttsteaa nbitnldee 2 | e: We acknowledge the overwhelmingly positive response from the specialty polymers 201Dat community. The breadth of participation in the symposium is due in part to the support from a September 7, Publication n IAnucCm.S;b tehfroe Wr o Ltfehu eobiarrrgri efzai onntliar znuCacltoyiioar plni nossd.ru aeptbIipotnoen rdpt; . aa trnotid c tuhlea r,n uwmee rthoaunsk atuhteh oArsC Sf oDr itvhiesiiro nt imofe lPyo leyfmfoertr Canhde mtois ttrhye, referees for their critical evaluation of the manuscripts. KATHLEEN O. HAVELKA The Lubrizol Corporation 29400 Lakeland Boulevard Wickliffe, OH 44092-2298 CHARLES L. MCCORMICK Department of Polymer Science University of Southern Mississippi Hattiesburg, MS 39046-0076 vii In Specialty Monomers and Polymers; Havelka, K., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2000. Chapter 1 Specialty Polymers: Diverse Properties and Applications Kathleen O. Havelka The Lubrizol Corporation, Research and Development, 29400 Lakeland Boulevard, Wickliffe, OH 44092-2298 Many of the most accessible commodity polymers have been studied in 1 00 detail and their applications have been developed extensively. Interest is h 5.c now focused on the synthesis and study of specialty polymers to meet 5 7 today's critical applications. Specialty polymers are primarily water 0 0- -soluble polymers with functional groups that are pendent to or on the 0 0 2 backbone; their global market value currently exceeds 9 billion dollars k- b and continues to grow (1). They are used extensively for their unique 1/ 02 solution properties in various fields of industry, agriculture, medicine, 1 0. biotechnology, and electronics. Applications of specialty polymers are 1 g doi: diverse, including: water treatment, paper processing, mineral http://pubs.acs.orMarch 27, 2000 | dmdsineirsukquplsugte ei rdfssuaetaendlnricdvittn ieitgoirfvoy,n e,rat sepl t,xeh ptterria looenppl edpieug rrmmtoisece esepnn,sr tsso ioi.dinrensug. .,c, t athpi eoet hnrspSi,co apeknineneachntli.a e acnrlac tTyrfeeo hd re p po raooil lelpd yvrauemeiccnlte otsro v,sm fe pramhyoya,uf rtcalemtolinsfaa outci nenapcugcrtttsoii ocvaaanisndla sdeal, 2 | e: properties depends on the type of polymer, the amount used, and 201Dat interactions with other chemistries in the formulation. September 7, Publication Tanhde deinvgeirnseee rpsr owpeorrtiledsw oidf es pbeecciaalutyse p oolfy mtheerisr aproet ecnaptitaulr ianpgp tlhicea itmioangs ininat imona noyf sacrieeansti sotsf present and future hi-tech and biological applications. Of particular interest is the ability to tailor a polymer to deliver a specified property in response to an external stimuli. This is highly desirable as it enables one to minimize both the amounts of material used and competitive reactions, which is critical in control-release functions, particularly in drug delivery applications. Effective delivery of drugs to a target cell or tissue largely diminishes adverse side effects and increases the pharmacological activity. It is the potential to tailor macromolecules to provide specified properties in an environmentally benign manner that motivates much of the current applied and fundamental research in the field of specialty polymers. These properties are critically needed for many of today's demanding applications. 2 © 2000 American Chemical Society In Specialty Monomers and Polymers; Havelka, K., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2000. 3 Material Considerations of Specialty Polymers There are numerous considerations in determining the appropriate polymer for a given application. In general, for a polymer to be commercially viable it must meet stringent environmental regulations, high performance standards, and be cost effective. The properties of specialty polymers depend on their basic chemical and structural properties, as summarized below. • Molecular Weight - The molecular weight and molecular weight distribution strongly affect the solution properties of specialty polymers and their applications. • Hydrophile to Lipophile Balance (HLB) ~ the type and content of hydrophiles and lipophiles significantly impacts specialty polymers inter- and intra-molecular associations. 01 • Sequence distribution of monomers — block, alternating, or random distribution 0 ch impacts interaction of monomer groups within the polymer. 5. 5 • Degree of Branching - a branched polymer frequently has different properties than 7 0 0- its linear analog, such as, lower tendency to crystallize, different solution 0 20 properties and light scattering behavior. bk- • Hyperbranched materials and dendrimers - offer the synthetic ability to chemically 1/ 2 tailor the branches in a step-wise fashion. 0 1 0. • Degree of crosslinking ~ a crosslinked polymer has chemical linkages between 1 http://pubs.acs.org March 27, 2000 | doi: • ccaddIohmheisnanatoriisracnuiibct nsyCtu.te , th raii Iao. nerpnda. o.,etc hltpthyeeeem rn pdm-er sreo Msirosee nnas hnc wiytehge hewlol lfeay ndts eua obr mlm yvsb eaoaent lresut ,rob iolailvtfel e uipcnssho tuc alirayrsolgm lsieynsed lvrsi snewg rkareseroeledluls ,yp pt bspho,ure loty c lpehedlosaoersrcetg itiseort o nncltaaoyynltt p e tsdeosw,.i sietsaTslonl hc.ld vre oeircs. hsiloaTirnnhgikece 2 | e: • Polyelectrolytes ~ macromolecules bearing a net charge 201Dat • anionic ~ macromolecules bearing a negative charge. September 7, Publication • rb•Pe eop leyecaiaattmht uieopnrnh itinoscel y-du titesrmspa lae~,rc s rheomadmv aiaocnllrogeonc mtughol etelh see scb ausemlaaemresi nencg uop mano tlpbayoeimnsr iietnorigv fc ehbc acaoihttnihao.r ngcTieach.t ieaossne i acpn oailonyndmi cea rnrsei opmneaiacyt units, or have a net charge of one sign. • Polybetaines ~ macromolecules containing both cationic and anionic charges on the same pendent group. • Degree of Chemical Modification - Synthetic macromolecules and many natural polymers (e.g., polysaccharides) can be chemically modified to adapt their properties to the needs of a particular application. For example, the ionic character of cellulose may be chemically modified from nonionic to anionic through nitration. Origins of Specialty Polymers Specialty polymers are typically water-soluble polymers that come from three origins, natural, semisynthetic, and synthetic macromolecules. Natural polymers are plant or In Specialty Monomers and Polymers; Havelka, K., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2000. 4 animal based materials such as cellulose and proteins. Semisynthetic polymers are modified natural polymers manufactured by chemical derivatization of natural organic macromolecules, generally based on polysaccharides. Synthetic polymers are obtained by the polymerization of monomers synthesized from petroleum or natural gas precursors. Natural and Semisynthetic Polymers A significant number of water-soluble polymers are derived from biological sources, biopolymers (2). Biopolymers are an abundant and diverse class of polymers that includes polysaccharides (3), polynucleotides (4), and proteins (5). Since these polymers perform unique biological functions, they have specific microstructures and are often monodisperse. 01 Polysaccharides are a diverse class of biological macromolecules with a wide range 0 ch of structural and behavioral characteristics (3). They are biodegradable, cyclolinear, 5. 5 polyhydroxyl compounds that are widely used in industry. Industrial polysaccharides 7 0 0- have traditionally been extracted from renewable resources like starch and gums from 0 0 plant seeds. 2 bk- Solution properties, such as solubility, viscosity, and phase behavior, are highly 21/ dependent on the macrostructure of the chain and the chemical microstructure of the 0 0.1 repeat units. The presence of acidic or basic functionality causes pH, electrolyte, and 1 http://pubs.acs.org March 27, 2000 | doi: thtmsaoeubymo ciddlhhripitoy feyaydprs t arh ootptohu gabferieoie nncrr-tm h dsg,ebe rohpioonlyenuokdndpgsrdisy,on e.p g gnoee tfrlT asbsaonh e andeshny a adhslvt thycileeoydam rorr.oe it nra,p Tontahrphdnoaie dmbci is ulocp inw qlhieauqaicsdiruusdmeeol alc acybrrci yeaaehstapuitnaoptaivdnllcsii/ aooe.h ldrrsaT .ost hiof n e bptsmeeoereal mypnnsr yooas lcpheccecoohruwmtaliaernmirs d eteaoarsrc se sisi aionlglacc nrmilagiuftaediitcloeeyasnr n i dtathuollyseef 2 | e: 201Dat Polynucleotides are biopolymers that carry genetic information involved in the ember 7, blication pocfor ompcrbeoistnseaeintsis oo ncfs ar enap nbldiec asmteiqaodunee an bncyde aplsersnoegtmethinbsl .is nyTgnh tethh ee2s 0i2s 0a(m 4a)im.n oiAn oan c aeidcssisde cns otiinnatl alvyian ri infoofuiunsr i tmme iacnjruoomrs tbtryeurpc,et usr aolf Sept Pu side chains, i.e., hydrophobic, hydrophilic, basic and acidic. Most polypeptides and proteins are water-soluble or water-swellable. The solubility of proteins varies considerably based on composition and condition of ionic strength, pH, and concentration. Those with the highest density of polar groups or electrolyte character are the most soluble. Therefore, solubility in water is lowest at the isoelectric point and increases with increasing basicity or acidity. Polynucleotides are utilized extensively in medical, industrial, and agricultural applications. The development of recombinant DNA techniques has led to the ability to clone genes and has facilitated the production of a large numbers of proteins with significant commercial potential (6). Among the first genetically engineered proteins are insulin, the pituitary growth hormone, and interferon. Other water-soluble proteins are isolated from biological sources in a more traditional manner for a number of commercial applications. Enzymes are used as detergent additives to hydrolyze polysaccharides and proteins, to isomerize various glucose and sucrose precursors, and for mineral recovery. Supported enzymes are becoming commercially significant for large-scale substrate conversion of macromolecules(7). In Specialty Monomers and Polymers; Havelka, K., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2000. 5 Commercial Advantages of Natural and Semisynthetic Polymers Natural and semisynthetic polymers have some commercial advantages over many synthetics, particularly in food applications. • FDA Status — Many have been assigned "generally recognized as safe" (GRAS) status by the US Food and Drug Administration (FDA). • Ease of Production - • The processes for producing natural polymers are frequently simpler, involving harvest and refinement through chemical and mechanical operations. • Semisynthetics involve chemically derivatizing natural macromolecules instead of complex polymerization of monomers. • The facilities for producing them, therefore, are less capital-intensive, and the equipment can be more flexible. 1 0 0 h 5.c Synthetic Polymers 5 7 Synthetic specialty polymers are obtained by the polymerization of monomers 0 0- synthesized from petroleum or natural gas precursors. Linear or branched 0 0 2 macromolecules may be formed from one or many monomers. Distribution of k- b monomers, along the backbone or side chain, can be controlled in a number of ways, 1/ 2 including: controlling monomer reactivity, concentration, addition order, and reaction 0 1 0. conditions. 1 http://pubs.acs.org March 27, 2000 | doi: prirrnaeionnialtgcdyi atomitcomeeondrM,m icfzaparoalejonttoeieudro rn irnntdac aidsooot.iinm fnc sgamf. ,luD leTnyberc,hpcl taoeieianorcnelinkd o a,sain nlyroiiegnzcr te anhdolguel nrytmvai ,cfi emtn or yosorslp un ecesomqac mutmioiaeoenlennrtoty cihmce soasptedrl orulsscyl c,ya.u t nmuscr eCaeebdrr,obe spt ootohapn lrepryyee rlm p epmampeorareolasryddne mo eo rs mue pbntreeeiydcrzr espiaa,rcot lihltooyyaanrmip np psme-ortgrlorasyrap yomirwn wieeabitdrtthehes 2 | e: in the research laboratory. However, only a few are of commercial interest. Of 201Dat particular commercial interest is synthesis of specialty polymers in solutions, ember 7, blication Cdiospmemrseiorncisa, ls uAsdpevnasniotangse, so ro fe mSyunlstihoentsi.c Polymers Sept Pu Synthetic, semisynthetic, and natural polymers frequently can perform similar functions. However, synthetic polymers have a number of inherent advantages and are preferred in many applications for a number of reasons, including: • Greater Flexibility - Synthetic polymers can be designed at the molecular level and are frequently used as model compounds to develop structure-property relationships for the more complex natural polymers. • Greater Versatility - Synthetic polymers can be tailored to provide a specific property or properties for a given application. The naturals and semisynthetics are limited in the types of chemical modification because of the fragile polysaccharide backbone. • Greater Efficacy - Since synthetic polymers can be tailored for a specific property, significantly less synthetic polymers are needed to facilitate the same performance as natural polymers. In Specialty Monomers and Polymers; Havelka, K., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2000. 6 • Lower Biological Oxygen Demand (BOD) - Since synthetic polymers have lower BOD, the effluents containing synthetic polymers are easier to treat than the other types. • Greater Product Consistency - Since the raw materials and the reaction conditions can be well defined and controlled, synthetic polymers can be manufactured with more consistent quality than natural or semisynthetic polymers. • Greater Price Control - Synthetics are less subject to variations in price than natural polymers due to availability. Functionality of Specialty Polymers Specialty polymers are best known for their built in functionality and water-solubility. This functionality is present in natural and synthetic polymers and can be broken down 01 into two broad categories nonionic and ionic polymers. These two categories will be 0 ch discussed in greater detail. 5. 5 7 0 0- Nonionic Polymers 0 0 Nonionic specialty polymers contain diverse functional groups that do not bear a 2 bk- charge, such as, vinyl esters, acrylates, acrylamides, imines, and ethers. Most of these 21/ commercially important polymers are soluble in water. Their water solubility is the 0 0.1 result of a high number of polar or hydrogen-bonding functional groups per repeat 1 http://pubs.acs.org March 27, 2000 | doi: uveAuxilncntairrytmay.l h lpaimglNmePho oio ondnlfmoey i emaooaicnelscreri hyccsu l uaapnlonmoiaqrdlri uy dtremhwei n eeeigiasrirm gs ocf hooopatrn mremegn(m 8eintd)veyg. ir pn fcirApyicoalola mltl lhmyal ypomtoh pufneelogoir crhifmmzar eatpeeietroodi-sonlr yansfabd r aocoeircrmcfeya a lslgua tfsiprmrvaeeoie ienldny-ieter m dba cdedealirriocinsinzaws glaob .t l epivco oeonpslm y oompfsly oleaomucrwnirezydlraylsita,z. i meoidntiA d oteinosf. 2 | e: soluble in water in all proportions. Since polyacrylamide can be polymerized to very 201Dat high molecular weight, it is a highly efficient viscosifier. Applications of ember 7, blication pmwoaoltyleearc cutrrlyealara tmmwieedniegts.h ti Anccpolpuprodolexy mifmloeacrstce uloylfa nsaetcsvr,e yrrlahalem ohiludonegd yar ercedo ntmhtierlo llim oanog spet onwutsni,d dase nloydf upasdoehldye aspcivoryelysla.m meirHd eifg oihrs Sept Pu used annually in water treatment, with a market value of approximately one billion dollars (9). Poly(ethylene oxide) is prepared by ring-opening polymerization of ethylene oxide. It is a white free-flowing powder with commercial grades ranging from 100,000 to 5,000,000 molecular weight (10). Polyethylene oxide)s are completely soluble in water at room temperature, but show a lower critical solution temperature (LCST) near the boiling point of water. The solution properties of poly(ethylene oxide)s have been extensively used in commercial applications for rheology control. The unique phase transition properties are being explored for control-release in thermally-responsive applications. Ionic Polymers Polymers possessing ionic groups pendent to the backbone are perhaps the most important class of macromolecules, ranging from biopolymers such as polynucleotides and proteins to technologically important rheology control agents and polysoaps. In Specialty Monomers and Polymers; Havelka, K., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2000. 7 These ion-containing polymers may be divided into two groups, polyelectrolytes and polyampholytes. Polyelectrolytes have either anionic or cationic groups along the chain while the polyampholytes have both anionic and cationic groups present. Both have high charge densities and typically are water-soluble. Water-soluble ionic polymers share a number of common properties with water-soluble nonionics, e.g., they both can act as viscosifiers. However, differences arise from the presence of charge on the macromolecular backbone and from the electrostatic interactions of mobile counterions. These differences have a significant impact on the structure of ionic polymers in solution and will be discussed further. Polyelectrolytes Polyelectrolytes are macromolecules bearing a net charge. Interest in these unique materials spans numerous and diverse areas. They have been investigated 1 0 because of their essential participation in biological systems, such as, conformation 0 h c transition of DNA (11). In ion-exchange membranes, they have been used for ion 5. 5 selectivity, such as recovery and separation of precious and heavy metals. Also they 7 0 0- have been explored in polyion gels for controlled release and phase transitions, such 0 20 as, drug delivery (12). Their molecular structure can be tailored to allow large bk- conformational changes with pH, temperature, or added electrolytes. Molecular 1/ 2 parameters that significantly influence behavior include: hydrophobic/hydrophilic 0 0.1 balance, molecular weight, number, type and distribution of charge on the 1 http://pubs.acs.org March 27, 2000 | doi: mcvisntooataulebcunriramltoeiczmertiaiC,ooo tinhnlaoesan nc idtnu,yw lcpabiocertiomh nn (dpbw1fiaoa3nactr)gatmk.e bbracio.ita SiinnzooeAa nl,tb u iocetadih nnoiaa,sdn rtlv aatpeincssrrctoceoeelodpru si,esb irotfiotiifliccfi e tfasycetf ihr eoidiaannnertgugc,p rleeauedunnd tddoii lnmfis ogzupoan soipt epilhttoyehyannees ls eeiifon cerbont xrem.tfo ehllo naycvttth eciosueo rlfa, i sbtii ohaotcnyhnkide,zb raooaatdndbioyehil,nnei sa tyiamao nntnidodc, 2 | e: attain large hydrodynamic volumes in deionized water at low concentrations (14). 201Dat This effect is caused by coulombic repulsion between charged groups along the ember 7, blication prsaaonlltdy, omcmoeur, lcohmeanbitnrico t phrieacptau lfllosyri coenfssa vtahoreere dcshh iaeiclnod neindfot,o ram lala ortwioodinn- lgik wteh iect hop nofloay rmmseaurt ibcoshnea.q iunIe ntno tt haesd supecmrereseae asn ecm e ooirnfe Sept Pu hydrodynamic volume. Electrostatic repulsions not only cause an increase in hydrodynamic volume but also increase shear sensitivity or non-Newtonian behavior. The extent of ionization of polyelectrolytes depends on the relative base or acid strength, degree of solvation, and dielectric constant of the solvent. The structure and properties of acidic (anionic) and basic (cationic) polyelectrolytes, are discussed further. Polyelectrolytes (Anionic) are macromolecules bearing a negative charge. Depending on the strength of the acid, they can strongly interact with positive charges. Anionic polyelectrolytes that have been studied extensively have primarily carboxylic or sulfonic acid functionality, including: poly(acrylic acid), poly(vinylsulfonic acid), poly(styrenesulfonic acid), poly(2-acrylamido-2-methylpropanesulfonic acid), poly(methacrylic acid), and their salts. Applications of anionic polyelectrolytes are diverse ranging from gels for medical applications to latex stabilizers and dye receptors in synthetic fibers. Polyelectrolytes (Cationic) are macromolecules bearing a positive charge. Cationic functional groups can strongly interact with suspended, negatively charged In Specialty Monomers and Polymers; Havelka, K., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2000.