I Introduction Polymer structures can be rougy divided into wocaersingle-chain structure and their assemblec structures. the first category,single-chai structures include the chemical structures and the conformations of polymer chain The chemical structures can be described at two separate levels,i.e.intrinsic and extrinsic levels,corresponding to their roles in the determination of polymer behaviors.The intrinsic factors are common for the same species of polymer samples,including the chain semi-flexibility and the complicated inter-chain interactions.The extrinsic factors are specific for the individual cases of polym samples including molecular v weights and their distributions,molecular top ite and the egular of chemical s and their ain. ation of polymer chai ses on the variation r vanous circumstances. In the second category,the assembly structures of polymer chains show both static and dynamic aspects.For the single-component homopolymer systems,the static structures include amor phous states,oriented states,liquid crystal states and crystalline states,whose domains can interwoven into the texture of materials.For the polymer-based multi-component systems,the above states can co-exist even in the mixed or separated phases of solutions,blends,copolymers and composites.The dynamic ted into nd crys stalline states.Most of the tates are form ed by the semi-crystallin e textu res that ppear a elasto ners.The non-crystalline states can be treated as glasses,rubbers or fluids according to the different length scales of molecular mobility. The physical properties of polymers vary with the structures hierarchical from chemical structures to chain conformations and their assembly structures.The mechanical properties are characterized by the impact strength,the tensile strength. the bending strength and the hardness of polymers.The thermodynamic properties are characterized by the heat resistance(physical aging,deformation temperature and de adation ter rature)and the sol of polyn to pho nic.ele magnetic.phono are sepa rately characterized by the transparency.the conductivity.the dielectri constant etc.The transport properties of polymers have been applied to characterize the filtration membranes for their efficiency of water purification.as well as the drag reduction agents to reduce the barrier for the enhanced oil recovery.for the long distance oil-piping and for the fire-extinction water-piping.The surface properties of polymers are characterized by the friction,the adhesion and the electrostatics The chemical properties of polymers are characterized by the chemical aging degradation and c -linking.Most of the above physical perties of polyr e been well e loited and be lied i daily life curren on to polymer physics. A such,it will mainly focus on polymer structures as well as their relationships with properties (as elucidated by statistical thermodynamic and kinetic theories of polymers).and may not be able to provide an extensive survey on polymer properties and their wide applications.For a complementary knowledge about polymer properties,the readers are directed to other textbooks of polymer physics or specialized monographs about certain polymer properties
Polymer structures can be roughly divided into two categories, i.e. single-chain structure and their assembled structures. In the first category, single-chain structures include the chemical structures and the conformations of polymer chains. The chemical structures can be described at two separate levels, i.e. intrinsic and extrinsic levels, corresponding to their roles in the determination of polymer behaviors. The intrinsic factors are common for the same species of polymer samples, including the chain semi-flexibility and the complicated inter-chain interactions. The extrinsic factors are specific for the individual cases of polymer samples, including molecular weights and their distributions, molecular topological architectures, and the regularities of chemical sequences and their connections along the chain. The conformation of polymer chains focuses on the variations of chain conformation under various circumstances. In the second category, the assembly structures of polymer chains show both static and dynamic aspects. For the single-component homopolymer systems, the static structures include amorphous states, oriented states, liquid crystal states and crystalline states, whose domains can interwoven into the texture of materials. For the polymer-based multi-component systems, the above states can co-exist even in the mixed or separated phases of solutions, blends, copolymers and composites. The dynamic structures can be separated into crystalline and non-crystalline states. Most of the crystalline states are formed by the semi-crystalline textures that appear as hard elastomers. The non-crystalline states can be treated as glasses, rubbers or fluids according to the different length scales of molecular mobility. The physical properties of polymers vary with the structures hierarchical from chemical structures to chain conformations and their assembly structures. The mechanical properties are characterized by the impact strength, the tensile strength, the bending strength and the hardness of polymers. The thermodynamic properties are characterized by the heat resistance (physical aging, deformation temperature and degradation temperature) and the solvent resistance of polymers. The responses to photonic, electronic, magnetic, phonon and microwave stimulations are separately characterized by the transparency, the conductivity, the dielectric constants, etc. The transport properties of polymers have been applied to characterize the filtration membranes for their efficiency of water purification, as well as the dragreduction agents to reduce the barrier for the enhanced oil recovery, for the longdistance oil-piping and for the fire-extinction water-piping. The surface properties of polymers are characterized by the friction, the adhesion and the electrostatics. The chemical properties of polymers are characterized by the chemical aging, degradation and cross-linking. Most of the above physical properties of polymers have been well exploited and been widely applied in our daily life. The current book is intended to be a concise introduction to polymer physics. As such, it will mainly focus on polymer structures as well as their relationships with properties (as elucidated by statistical thermodynamic and kinetic theories of polymers), and may not be able to provide an extensive survey on polymer properties and their wide applications. For a complementary knowledge about polymer properties, the readers are directed to other textbooks of polymer physics or specialized monographs about certain polymer properties. 8 1 Introduction
References 9 Question Sets 1.Why do we say that polymer physics mainly focuses on the chain-like 2.Why do polymers belong to soft matter? 3.Try to summarize the importance of Brownian motions in polymer physics References Binnig G.Rohrer H(1986)Scanning tunneling microscopy.IBMJRes Dev 30:355-369 Boltzmann L (1872)We Studien tiber da orgleichgewicht unter Gasmoleklen Dalton J ()A of che ophy.Part 1.Manchester.Printed by S.Russell for R.Bickerstaff,London er1:16 ctischen The rie der Warm eforderte P.Stepto RF volutions.3rd edn.The University of Chicago Press c air:with s(trans:Henry T) Lehn J-M(1995)Supramolecular chemistry:concepts and perspectives.Wiley-VCH,Weinheim Rupp R (2005)Four elements:water air fire Earth.Profile Books Lid.London Staudinger H (953)Ma H Te Swedish Acade my of lecture.pdf Wunderlich B(1990)Thermal analysis.Academic.New York
Question Sets 1. Why do we say that polymer physics mainly focuses on the chain-like structures? 2. Why do polymers belong to soft matter? 3. Try to summarize the importance of Brownian motions in polymer physics. References Binnig G, Rohrer H (1986) Scanning tunneling microscopy. IBM J Res Dev 30:355–369 Boltzmann L (1872) Weitere Studien u¨ber das Wo¨rmegleichgewicht unter Gasmoleku¨len. Sitzungsberichte Akad Wiss, Vienna, part II 66:275–370 Dalton J (1808) A new system of chemical philosophy. Part 1. Manchester, Printed by S. Russell for R. Bickerstaff, London de Gennes PG (1992) Soft matter. Rev Mod Phys 64:645–648 de Gennes PG (2005) Soft matter: more than words. Soft Matter 1:16 Einstein A (1905) U¨ ber die von der molekularkinetischen Theorie der Wa¨rme geforderte Bewegung von in ruhenden Flu¨ssigkeiten suspendierten Teilchen. Ann Phys 17:549–560 Jenkins AD, Kratochvı´l P, Stepto RFT, Suter UW (1996) Glossary of basic terms in polymer science. Pure Appl Chem 68:2287–2311 Kuhn T (1996) The structure of scientific revolutions, 3rd edn. The University of Chicago Press, Chicago Lavoisier AL (1783) Essays on the effects produced by various processes on atmospheric air: with a particular view to an investigation of the constitution of the acids (trans: Henry T). Warrington Lehn J-M (1995) Supramolecular chemistry: concepts and perspectives. Wiley-VCH, Weinheim Rupp R (2005) Four elements: water air fire Earth. Profile Books Ltd, London Staudinger H (1920) U¨ ber Polymerisation. Ber dtsch Chem Ges A/B 53:1073–1085 Staudinger H (1953) Macromolecular chemistry: nobel lecture. The Royal Swedish Academy of Sciences, Stockholm, http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1953/staudingerlecture.pdf Wunderlich B (1990) Thermal analysis. Academic, New York References 9
Part I Chain Structure
Part I Chain Structure
Chapter 2 Structure-Property Relationships 2.1 Characterization of Chemical Structures Polymer chain structures include the chemical structures (known as primary structures)and conformation structures (known as secondary structures and further assembly structures).We first introduce the characterization of chemical structures of polymer chains,followed in the next chapters by the Gaussian treatment of their ideal-chain conformations and by the scaling analysis of their non-ideal-chain conformations,respectively.The conformations of self-assembled block copolymers as well as the conformations of crystalline polymers will be introduced in Chaps.9and nship between chemical structures and their physical performa of pol ded a who f names to c d chemical structures of polymer chains and thei derivatives.However,in our daily communication.people prefer to use the popular names of polymers reflecting their characteristic physical performances,such as high-density polyethylene(HDPE),foamed polystyrene,thermoplastic elastomers. liquid crystal polymers,conductive polymers,and polyelectrolyte.Such terminology allows us to comprehend quickly the basic characteristics of chemical structures responsible for their specific physical properties. In fact.as long g as we have obtained lymer sample,we need first to determine itsbasic phys proper The determin es on the key informa ion about the ch ails oft at sample.In other word we need to carry ou the necessary characterization of the chemical structures of polymer chains.Here rises a question,what are the essential factors characterizing the chemical structures of polymer chains,from which we can make a proper speculation on the funda- mental physical properties? To answer the question above,we shall begin with an analogy to the characteri- zation of a single crystal,for example,a piece of diamond.First,the single crystal possesses intrinsic structural symmetry.For diamond,the sp'hybrid orbits of the carbon atoms lead to a tetrahedral structure for the most stable packing of carbor W.Hu,Polymer Physics,D0I10.1007978-3-7091-0670-9_2. 13 C Springer-Verlag Wien 2013
Chapter 2 Structure–Property Relationships 2.1 Characterization of Chemical Structures Polymer chain structures include the chemical structures (known as primary structures) and conformation structures (known as secondary structures and further assembly structures). We first introduce the characterization of chemical structures of polymer chains, followed in the next chapters by the Gaussian treatment of their ideal-chain conformations and by the scaling analysis of their non-ideal-chain conformations, respectively. The conformations of self-assembled block copolymers as well as the conformations of crystalline polymers will be introduced in Chaps. 9 and 10, respectively. The relationship between chemical structures and their physical performance is one of the central topics of polymer physics. IUPAC has recommended a whole set of names to describe the detailed chemical structures of polymer chains and their derivatives. However, in our daily communication, people prefer to use the popular names of polymers reflecting their characteristic physical performances, such as high-density polyethylene (HDPE), foamed polystyrene, thermoplastic elastomers, liquid crystal polymers, conductive polymers, and polyelectrolyte. Such terminology allows us to comprehend quickly the basic characteristics of chemical structures responsible for their specific physical properties. In fact, as long as we have obtained a polymer sample, we need first to determine its basic physical properties. The determination mainly relies on the key information about the chemical details of that sample. In other words, we need to carry out the necessary characterization of the chemical structures of polymer chains. Here rises a question, what are the essential factors characterizing the chemical structures of polymer chains, from which we can make a proper speculation on the fundamental physical properties? To answer the question above, we shall begin with an analogy to the characterization of a single crystal, for example, a piece of diamond. First, the single crystal possesses intrinsic structural symmetry. For diamond, the sp3 hybrid orbits of the carbon atoms lead to a tetrahedral structure for the most stable packing of carbon W. Hu, Polymer Physics, DOI 10.1007/978-3-7091-0670-9_2, # Springer-Verlag Wien 2013 13
14 2 Structure-Property Relationships atoms in the diamond.The s the azimuths e most stable geom etric conformation of molecules ofter mine f the packing neighbors,i.e.the angles betwe een two axe of the unit cell.Second,the single crystal has an intrinsic periodicity for the stacking of the structural units.characterized by.for diamond.the carbon-carbor bond lengths.The interactions between the structural units determine the axial lengths of the unit cell.Besides the above two intrinsic factors reflecting the common properties of the same species of single crystals,the single crystal contains some extrinsic characteristic features on its individual structure,i.e.the sizes.the and the inter rnal defects.Fora e of diamond,these extrinsic chara cteristi 吃 ha acterized at the price rinsic and extrinsic levels facilitates a better understanding of onship to performances One can describe polymer samples in a similar way.First of all.a polymer chair possesses semi-flexibility.that characterizes the intra-chain interactions for the most stable conformation persisting along the chain axis.Secondly,a polymer chain alsc holds complex inter-chain interactions.These two intrinsic characteristic factors dictate the basic physical behaviors of the same species of polymers.Besides these two intrinsic fact each individual polymer s mple po sesses certain extrinsic istic fac .i.e.,mole and h pologica chitecture and equen irregularities ese extrir acteristic f actors are also important in determining the physical behaviors of the polymer samples The separation of chemical factors of polymer chains into the intrinsic and extrinsic levels allows us to understand their corresponding roles in determining the physical behaviors of polymers.The intrinsic chain structures play a primary role in determining physical behaviors.They often serve as the thermodynamic driving forces for structural phase transitions.In contrast,the extrinsic chain struc res play a secondary role in determining physical behaviors.They usually serve as the ktemal restrictions for struct transitions For th isotropic attraction king fpolymer chains, whi many randoml distributed irregular structural units along the sequence of the chain(see Sect.2.6 for more details),the capability of polymer crystallization will be ruined.There fore,random copolymers often stay in the non-crystalline state and exhibit the characteristics of amorphous polymers,such as atactic polystyrene (aPS)and atactic poly(methyl methacrylate)(PMMA). The following text will introduce five intrinsic and extrinsic chemical factors above.as well as their relationships with physical properties of polymers. 2.2 Semi-Flexibility of Polymer Chains Many factors may determine polymer semi-flexibility,such as internal rotation solvation,stretching,spatial confinement,surface adsorption,charge interactions hydrogen bonding along helix,and double helix of DNA,etc.The most common factor is the internal rotation.One can understand the internal rotation from the
atoms in the diamond. The most stable geometric conformation of molecules often determines the azimuths of the packing neighbors, i.e., the angles between two axes of the unit cell. Second, the single crystal has an intrinsic periodicity for the stacking of the structural units, characterized by, for diamond, the carbon-carbon bond lengths. The interactions between the structural units determine the axial lengths of the unit cell. Besides the above two intrinsic factors reflecting the common properties of the same species of single crystals, the single crystal contains some extrinsic characteristic features on its individual structure, i.e., the sizes, the facets and the internal defects. For a piece of diamond, these extrinsic characteristic factors mainly determine its market price. The diamond structure characterized separately at the intrinsic and extrinsic levels facilitates a better understanding of its relationship to performances. One can describe polymer samples in a similar way. First of all, a polymer chain possesses semi-flexibility, that characterizes the intra-chain interactions for the most stable conformation persisting along the chain axis. Secondly, a polymer chain also holds complex inter-chain interactions. These two intrinsic characteristic factors dictate the basic physical behaviors of the same species of polymers. Besides these two intrinsic factors, each individual polymer sample possesses certain extrinsic characteristic factors, i.e., molecular weights and their distributions, topological architectures, and sequence irregularities. These extrinsic characteristic factors are also important in determining the physical behaviors of the polymer samples. The separation of chemical factors of polymer chains into the intrinsic and extrinsic levels allows us to understand their corresponding roles in determining the physical behaviors of polymers. The intrinsic chain structures play a primary role in determining physical behaviors. They often serve as the thermodynamic driving forces for structural phase transitions. In contrast, the extrinsic chain structures play a secondary role in determining physical behaviors. They usually serve as the external restrictions for structural phase transitions. For instance, the anisotropic attractions represent the compact packing of polymer chains, which drive polymer crystallization. If polymer chains contain too many randomly distributed irregular structural units along the sequence of the chain (see Sect. 2.6 for more details), the capability of polymer crystallization will be ruined. Therefore, random copolymers often stay in the non-crystalline state and exhibit the characteristics of amorphous polymers, such as atactic polystyrene (aPS) and atactic poly(methyl methacrylate) (PMMA). The following text will introduce five intrinsic and extrinsic chemical factors above, as well as their relationships with physical properties of polymers. 2.2 Semi-Flexibility of Polymer Chains Many factors may determine polymer semi-flexibility, such as internal rotation, solvation, stretching, spatial confinement, surface adsorption, charge interactions, hydrogen bonding along helix, and double helix of DNA, etc. The most common factor is the internal rotation. One can understand the internal rotation from the 14 2 Structure–Property Relationships