Main lectures

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Institut Charles Sadron CNRS UPR 22

6, rue Boussingault


Polymer-solvent compounds (either complexes or intercalates) can be prepared under various conditions: 1) by cooling homogeneous polymer solutions, or 2) by exposing solid polymer samples (films or bulk samples) to the liquid solvent or to its vapours at a temperature well below the compound melting temperature. One way of studying the outcomes of these different ways of preparation is to establish the temperature-concentration phase diagrams. After discussing the potentiality of these phase diagrams for characterizing the systems under study, the results will be presented on compounds involving isotactic and syndiotactic polystyrenes. The various structures and morphologies will be also presented. It will be particularly shown that the path followed to reach a T,C coordinate of the phase diagram (decreasing T at constant concentration C or decreasing C at constant temperature T) has no significant effect on the melting behaviour of the various systems.


Microscopically-viewed Structural Changes in Solvent-induced phase transitions of synthetic polymers


Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan

Solvent-induced Crystallization of syndiotactic Polystyrene

Syndiotactic polystyrene is known to crystallize from the glassy state to the -form by absorbing organic solvent such as toluene, benzene, chloroform, etc. This -form is a polymer-solvent complex, in which the helical chains and solvent molecules are packed together. In order to clarify the transition mechanism from the microscopic point of view, we performed time-resolved measurements of X-ray diffraction, infrared spectra and Raman spectra in this solvent-induced crystallization process. On the basis of a concept of critical sequence length for the infrared and Raman bands, we could imagine concretely the growth of helical chains and combined this conformational change with the formation of crystal lattice as informed by X-ray diffraction data. The quantitative analysis of half-width of infrared bands intrinsic to the amorphous phase told us that the molecular motion of the random coils is enhanced even below the glass transition temperature through the interactions with solvent. By combining all these information together, the structural formation process could be clarified as shown in the above figure.

Water-induced Phase Transitions of Poly(ethylene imine)

Poly(ethylene imine) shows a structural change between a doubly-stranded helix in a dry state and a planar-zigzag all-trans chain in humid state by supplying water vapor. The zigzag chains form stoichiometric hydrates with water through the intermolecular hydrogen bonds. Time-resolved measurements of infrared spectra were carried out in the hydration process and the detailed information could be obtained as for the structural transformation between these anhydrate and hydrates.


Highly conductive oriented Polymer electrolytes

D. Golodnitsky*, E. Livshits, E. Peled

School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel


The growing interest in the ion-conducting polymers is mainly a result of the development of high quality processable and environmentally stable materials for use in items such as rechargeable batteries, electrochromic devices and sensors. Moreover, polymer electrolytes are of theoretical interest as model materials for the investigation of conduction paths in semicrystalline systems.

It is generally acknowledged that the macroscopic properties of polymeric materials are strongly influenced by their structural organization, which in turn may be affected by physical treatment. Molecular architecture plays an important role in determining the ionic conductivity of polymer electrolytes. It has been suggested that the ion transfer is driven by competing inter- and intramolecular interactions. Ions are thought to be transported by the quasi-random motion of short polymer segments and the conductivity is generally observed to rise with increasing flexibility of the polymer chains. In the polymer-salt complexes of polyethylene oxide (PEO), cations are enclosed within the PEO helices, thus suggesting the possibility of efficient cation transport along the helical axis.

We have employed a variety of experimental methods, including DC and AC conductivity, scanning electron microscopy (SEM), atomic-force microscopy (AFM), X-ray diffraction, differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR) spectroscopy, and pulsed field gradient nuclear magnetic resonance (NMR) to investigate the effect of stretching in poly(ethylene oxide) (PEO):LiX systems. Our studies show that macroscopic stretch is fully reflected in the microscopic distortion of the as-cast structure of polymer electrolytes. In semicrystalline complexes of PEO with different salts, such as lithium iodide, lithium trifluoromethanesulfonate, lithium trifluoromethanesulfonimide, lithium hexafluoroarsenate and lithium bis(oxalato)borate, enhancement of the stretching-induced longitudinal DC conductivity by a factor of 5 to 40 was observed, in spite of the formation of a more ordered polymer electrolyte (PE) structure. It was found that the more amorphous the PE, the less its lengthwise conductivity is influenced by stretching. The results of our investigation support the idea of preferential ionic transport along the PEO helical axis in the crystalline phase and offer a fertile field for research and development in the synthesis of new rigid polymers with ordered channels and composition appropriate for enhanced ionic conductivity.




University Louis Pasteur, Institut Le Bel, 4, rue Blaise Pascal, 67000 Strasbourg, France,

The development of concepts and strategies allowing the design of molecular networks with predicted and programmed structures is a topic of active investigations in research groups throughout the world. The engineering of molecular networks involves modeling, synthesis and exploitation of crystalline solids with predefined connectivity patterns between molecules or ions. As such, molecular network engineering, a subset of crystal engineering, is at the intersection of supramolecular chemistry and materials chemistry.

What has been accomplished: Structural molecular networks: Molecular networks are defined as supramolecular structures possessing translational symmetry. Whereas molecules are described as assemblies of atoms interconnected by covalent bonds, by analogy, one may describe molecular networks as hypermolecules for which the connectivity between the elementary molecular components (tectons) is ensured by non-covalent and/or reversible interactions. The formation of these molecular solids results from the chemical and physical nature of the molecular components comprising the solid. The design and formation of large molecular networks (10-6-10-3 m scale), may hardly be envisaged through a step-by-step type strategy. However, the preparation of such higher-order materials may be achieved through iterative self-assembling processes that engage programmed tectons. Thus, by programming (storage of both recognition and iteration information) specific interaction patterns between tectons in the crystalline phase, a variety of molecular (hydrogen bonded-, inclusion-, coordination-) networks with various dimensionality may be designed.

What remains to be accomplished: Functional molecular networks: Thus far, the approaches employed are mainly concerned with structural control of the formation of molecular networks. Obviously, a further step, which remains to be achieved, will be to use the structural knowledge gathered over the last decade for the design of functional networks. One may foresee that the majority of molecular materials for the next century might be based on functional molecular networks. In particular, using physical properties such magnetism, conductivity, optical and/or electronic features, new materials with applications in the field of storage, sensing, signal treatment, transduction and decontamination will be designed and prepared.




Polymer Science Unit, Indian Association For The Cultivation Of Science Jadavpur, Calcutta - 700032, INDIA, E-mail:

The surface morphology of the thermoreversible polyaniline (PANI) gels prepared with dinonylnaphthalene sulfonic acid (DNNSA), dinonylnaphthalene disulfonic acid (DNNDSA), (±) camphor-10 - sulfonic acid (CSA) and n-dodecyloxo sulfonic acid (DOSA) are studied using atomic force microscopy (AFM) for 15% PANI concentration (w/w). The AFM study clearly reveals the formation of lamellar morphology in the gel. A representative AFM picture showing lamellar morphology is presented in Fig.-1 for the PANI - DNNSA system. X -ray scattering experiments of these gels also support the lamellar structure formation and the lamellar thickness measured from it remains invariant with composition for the PANI - DNNSA and PANI - DNNDSA systems. In PANI - CSA and in PANI -DOSA systems the lamellar thicknesses vary with PANI concentration. Both X ray diffraction and electron diffraction experiments on the gels of different compositions of PANI - DNNSA and PANI - DNNDSA systems indicate new spacings of lower dhkl values which are invariant with composition. Similar observations are also found in PANI - CSA and in PANI - DOSA systems. These results indicate the formation of new unit cells in the lamella due to the microcrystallization of elongated surfactant tails formed under the doped condition. The dhkl values characterizing the lamellar thickness, bilayer thickness and monolayer thickness are discussed in view of molecular mechanics calculations using MMX program. The composition dependency of the lamellar thickness is discussed from the cohesive force of the surfactant tails within the lamella.

Fig. 1




B. I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, Prospekt F. Skariny 70, Minsk, 220072, Belarus,

Stereoregular PMMA (isotactic (i-PMMA) and syndiotactic (s-PMMA)) polymers display the strongest effect of tacticity on physical properties among all strereoregular polymers studied so far. I-PMMA and s-PMMA differ markedly in the glass transition temperature, chain stiffness, miscibility, surface activity, and adsorption behavior. The fact that these physically unlike macromolecules strongly attract each other with the resultant formation of stereocomplexes is really remarkable. Although stereoregular PMMAs and the stereocomplex have been the subj ect of intensive studies over the last three decades, their conformational characteristics are still a matter of debate and controversy.

Herein, we contribute to this field by variable-temperature FTIR measurements on amorphous films of isotactic and syndiotactic PMMA, followed by a detailed analysis of the temperature dependence of integrated band intensities for C-O stretching modes in the region 1050-1300 cm-1. The use of computerized FTIR instrumentation and modern methods of quantitative band-fitting analysis in combination with the recent IR and ab initio results for simple esters allowed us to achieve, for the first time, the unambiguous conformational assignment for the C-O bands of PMMA. This, in turn, enabled reliable IR spectroscopic determination of the difference in the energy of accessible conformational states for the backbone and for the ester group. Finally, detailed analyses of the C-O band intensities in transmission FTIR and ATR-FTIR spectra of single-component and stereocomplex PMMA films, based on the established band assignments, revealed new features in the bulk and surface structure of these important materials.


In printed form only



Fiber & Polymer Science Program, North Carolina State University, Raleigh, NC 27695-8301, USA

We and several other research groups have recently reported the ability of cyclodextrins (CDs) to act as hosts in the formation of inclusion compounds (ICs) with guest polymers. Polymer-CD-ICs are crystalline materials formed by the close packing of host CD stacks, which results in a continuous channel of ~5-10 A. in diameter running down the interior of the CD stacks. The guest polymers are confined to the narrow, continuous CD channels, and so are necessarily highly extended and segregated from neighboring polymer chains by the walls of the CD stacks. We have shown that coalescence of guest polymers from their CD-IC crystals can result in a significant reorganization of the structures, morphologies, and even conformations that are normally observed in their bulk samples. For example, when poly(ethylene terephthalate) (PET) is coalesced from its g-CD-IC, we find that in the non-crystalline regions of the sample the PET chains are adopting highly extended kink conformations, which result in their facile recrystallization from the melt and prevent quenching of the coalesced PET to achieve an amorphous sample during rapid cooling from above Tm. We have also created well-mixed blends of normally incompatible polymers by coalescing them from CD-ICs containing both polymers, where they are necessarily spatially proximal. Finally we have found the unique morphologies created by the coalescence of homopolymers, block copolymers, and homopolymer pairs from their CD-ICs are generally stable ta heat treatment for prolonged periods above their Tm's and/or Tg's, and so may be thermoplastically processed without loss of the unique morphologies achieved through coalescence from their CD-I~ crystals.

* The following colleagues (C. C. Rusa, X. Shuai, T. A. Bullions, C. M. Balik, D. I Shin, and J.L. White) and students (M. Wei, F. E. Porbeni, M. J. Gerber, E.Edeki, W. davis, and B. Urban) have been active collaborators and the U.S. Dept. of Commerce (National Textile Center) and U.S. Army (ARO) have generousty sponsored this research.





Department of Chemical and Biosystem Sciences,

University of Siena, Via Aldo Moro,2 - 53100 Siena, Italy - e-mail:

Water-macromolecule and ligand-macromolecule interactions are different phenomena and have different chemical and biological importance. However both solvent-macromolecule and ligand-macromolecule interaction can be studied using similar approaches based on selective NMR relaxation experiments. Macromolecules in solution induce solvent-solute interactions. The extent of interaction can be studied by checking the solvent parameters mostly affected by the presence of a large, slowly reorienting biomacromolecule. Water proton relaxation rates have been used to investigate different systems and phenomena, and theoretical interpretations of the experimental results have been proposed. In this paper both the water proton spin-lattice relaxation rates and are analyzed considering all possible sources of dipolar contributions. On the basis of the discussed equations, the average effective rotational water correlation time was calculated. The c value obtained in the binary water-macromolecule system is then compared with the value obtained in the water-macromolecule-ligand ternary system. The result shows that this approach could be used as a parameter to monitor the extent of solute-solvent interaction and to detect the effects of the ligand molecules on receptor proteins as a consequence of the recognition process. Selective and non-selective spin-lattice relaxation rates were also used to investigate ligand-macromolecules interactions. Several experimental and theoretical approaches have been developed to study the recognition processes between ligands and receptors, including methods based on Nuclear Magnetic Resonance (NMR) analysis of the solution behaviour of the ligand in the presence of receptors. In this case the analysis is based on the comparison of selective () and non-selective () spin-lattice relaxation rate analysis of the ligand in the presence and absence of macromolecular receptors and on the and temperature dependence analysis. From these studies, the ligand-receptor binding strength was defined on the basis of the ”affinity index”. An index derived on the basis of specific consideration about the macromolecule-ligand equilibrium kinetics.


Force spectroscopy studies of complexes with single polymer molecules

M.J. Miles

H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, United Kingdom

Atomic force microscopy (AFM) has been relatively little used in the study of polymer-solvent interactions. However, it has great potential to provide complementary information to existing techniques in this field. In this presentation, four AFM techniques which appear to be most promising will be presented and some examples will be given.

The areas in which AFM measurements can contribute to the study of polymer-solvent complexes are: (i) imaging, (ii) force recognition, (iii) force spectroscopy, and (iv) microcantilever sensors.

  1. AFM is capable of imaging single molecules at high resolution. From such images, it is possible to determine the flexibility and persistence length of individual molecules in the environments of various solvents. High-resolution imaging might be capable of following structural changes in, for example, the helical repeat or molecular width as a function of the solvent environment. It might even been possible to image individual complexed solvent molecules, but this would certainly be extremely demanding technically. The related technique of scanning near-field optical microscopy might also make a contribution by providing optical information beyond the diffraction limit.
  2. Force recognition involves functionalizing the AFM tip with a test molecule, for example, a solvent molecule, and testing its interaction against a polymer molecule. In this way, the interaction forces, and ultimately the binding energies of such interactions might be measured.
  3. Force spectroscopy is a single molecule technique in which a polymer molecule is extended between a fixed surface and the AFM tip. A force-extension curve is obtained. Such measurements could be performed with and without the presence of a particular solvent and the change in mechanical properties of complexation determined. During the extension, changes in the helical/secondary structure can be detected and the used of the dynamic version of this technique allows the complex mechanical properties to be measured during transitions. This is the most promising technique and some data on the effect of complexation will be presented.
  4. AFM technology is proving to be very valuable in the development of new micro sensors. In this technique, an AFM force-sensing cantilever is coated with polymer molecules and the response of the cantilever to the presence of solvent molecules can provide information on the nature of the interaction.




aLaboratory of Polymer Chemistry, Materials Science Centre, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands

bDepartment of Engineering Physics and Mathematics, and Center for New Materials, Helsinki University of Technology, P.O. Box 2200, FIN-02015 HUT, Finland

Self-assembly of polymeric supramolecules obtained by recognition driven supramolecule formation in polymers is a very powerful tool to produce functional polymer materials. The concept is illustrated using comb-shaped architectures. The physically bonded side chains can have two separate ”functions”. For example, in addition to providing a repulsive side chain required for self-organization, they may contain an acidic group that simultaneously acts as a dopant for a conjugated polymer such as polyaniline, which leads to electronic conductivity. Another example involves polarized luminance in solid state films of rod-like polymers obtained by removing the hydrogen bonded side chains from the thermotropic smectic phase. To increase complexity, one can incorporate structural hierarchies. This can be accomplished by applying within a single material different self-organization and recognition mechanisms operating at different length scales. For example, block copolymeric self-organization at the 100-2000 Å length scale and polymer/amphiphiles self-organization at the 10-60 Å length scale can be combined. Upon selective ”doping” of one block, conductivity can be switched based on a sequence of phase transition. Macroscopically tridirectional protonic conductivity can be accomplished by flow-orienting the local structures. There is a rich variety of phases, eg. lamellae-within-cylinders, which also allow selective cleaving of the constituents which form the supramolecules. For example, starting from polystyrene-block-poly(4-vinyl pyridine) where pentadecylphenol has been hydrogen bonded, one obtains a structure where the glassy polystyrene matrix contains empty cylindrical pores with poly(4-vinylpyridine) brushes at the walls. By selecting different block copolymers and amphiphiles, one can tune the wettability of the pore walls. In principle even the conformations of the brushes can be controlled by selecting the polymer and solvent properly. Finally, selective cleaving of the constituents, which form the supramolecules, also allows the preparation of a variety of nano-objects.