No description available.

In recent years supramolecular chemistry has established as one of the most active fields of science. The most significant feature of supramolecular chemistry is the use of building blocks which reversibly held together by intermolecular forces, electrostatic or H-bonding. Therefore, the synthesis of supramolecular systems using different non-covalent assemblies provides some unique architectures and features which are extremely difficult to be obtained via covalent synthesis. One main application of such influencing supramolecular systems is the preparation of self-healing materials. Among various approaches to self-healing effects, reversible bond formation has become prominent in the last years. To achieve both acceptable mechanical performance and self-healing behaviour from a polymeric material, proper balance between covalent and non-covalent bonding is important. The covalent bonding gives a basic strength to the material while the non-covalent bonding generates self-healing effects in the case of damage. The main aim of this study was to synthesize an organic moiety which is capable of forming supramolecular assemblies in the presence of suitable counterparts, followed by its incorporation on to polymer matrix and investigation of the final properties. For reversible bond forming technique H-bonding is exploited in this work. 4-substituted-2,6-diaminopyridine is selected as the organic moiety as it has a clear DAD (donor-acceptor-donor) structure and thus able to undergo self-association or triple hydrogen bonded complex formation with respective counterparts. Chichibabin reaction was utilised for the synthesis and 4-hydroxy-2,6-diamido pyridine was synthesised as the key compound. Initially different derivatives of 4-hydroxy-2,6 diamino pyridine was synthesized and utilised towards the formation of supramolecular network with a suitable monomeric counterpart. Poly (butadiene-co-maleic anhydride) is used as the base polymer as it has the possibility to introduce non-covalent bonding sites through grafting reactions on the double bonds or on maleic anhydride groups. The free amine group present in the main compound was grafted onto the backbone of poly (butadiene-co-maleic anhydride) via reaction of amine with maleic anhydride group. The main design of supramolecular self-assembly within poly (butadiene-co-maleic anhydride) with a suitable counterpart poly (butadiene-co-maleimide), is prepared and used in this thesis. The miscibility of the two polymers is proven by the presence of a single Tg in the DSC results of the mixture and also by the formation of homogeneous films with no phase separation in AFM. However the formation of hydrogen bonding within the monomer was proven by 1H NMR, IR studies. Further formation of complex between two polymers was established from the results of viscosity. Also the interactions between the complexes exert a distinct influence on the rheological behavior of the blend. Lastly the reversibility of this supramolecular blend was assured by temperature dependent viscosity values. In the final part of this work, bromobutyl rubber (BIIR) is selected as the model elastomer which has vast application in the tire industry; as the inner-liner that holds the air in the tire and also used as rubber stoppers for sealing medicine vials and bottles The bromine functionality can be substituted with an amine group making it more susceptible towards the incorporation of different organic moieties. In this way, the derivative of 2,6-diaminopyridine having a pendant amine group is incorporated in BIIR. As a counterpart uracil is used as its H-bond forming ability with diaminopyridine moieties is well established and supported by different previous research works. The supramolecular network formed between these two monomers help to generate self-healing effects within BIIR rubber. Fig. 2 represents the supramolecular network formed between chains of BIIR. The self-healing effect of the rubber material is examined through the stress-strain experiments where up to 82% healing was observed when heated up to 70 °C. With increasing temperature better healing was observed whereas at room temperature a 40% healing tendency was noticed. It is also interesting to note that the thermal and dynamic mechanical properties of this tailor made self-healing BIIR is identical with sulphur cured conventional BIIR.

Crystal structures of anhydrous pinacol, the hexagonal pinacol, pinacol monohydrate, and pinacol hexahydrate were studied. In all the structures crystal packing is unusual and complicated. The origin of the complexity may be the difficulty in filling space densely and while also satisfying the H-bonding requirements when the molecule has few internal degrees of freedom. Five 15-crown-5 complexes of M(NO3)2 (M = Cu, Zn, Mg, Co, Mn) were synthesized and characterized using X-ray diffraction and differential scanning calorimetry. The system is rich in polymorphs. Nine definite solid-state phases were identified. More phases probably exist in the solid state at temperatures slightly above the room temperature. Most phase transformations in this system take place in single crystals without the loss of crystallinity. The nine phases crystallize in five crystal structures. The crown ether ligands have very similar conformation in all the structures. The asymmetric units in all the structures are complicated and pseudosymmetric, which is the consequence of the presence of the packing problem. The origin of the packing problem that leads to the complicated phase behavior is the odd number of -CH2-O-CH2- units in the crown ether ligand.

In recent years supramolecular chemistry has established as one of the most active fields of science. The most significant feature of supramolecular chemistry is the use of building blocks which reversibly held together by intermolecular forces, electrostatic or H-bonding. Therefore, the synthesis of supramolecular systems using different non-covalent assemblies provides some unique architectures and features which are extremely difficult to be obtained via covalent synthesis. One main application of such influencing supramolecular systems is the preparation of self-healing materials. Among various approaches to self-healing effects, reversible bond formation has become prominent in the last years. To achieve both acceptable mechanical performance and self-healing behaviour from a polymeric material, proper balance between covalent and non-covalent bonding is important. The covalent bonding gives a basic strength to the material while the non-covalent bonding generates self-healing effects in the case of damage. The main aim of this study was to synthesize an organic moiety which is capable of forming supramolecular assemblies in the presence of suitable counterparts, followed by its incorporation on to polymer matrix and investigation of the final properties. For reversible bond forming technique H-bonding is exploited in this work. 4-substituted-2,6-diaminopyridine is selected as the organic moiety as it has a clear DAD (donor-acceptor-donor) structure and thus able to undergo self-association or triple hydrogen bonded complex formation with respective counterparts. Chichibabin reaction was utilised for the synthesis and 4-hydroxy-2,6-diamido pyridine was synthesised as the key compound. Initially different derivatives of 4-hydroxy-2,6 diamino pyridine was synthesized and utilised towards the formation of supramolecular network with a suitable monomeric counterpart. Poly (butadiene-co-maleic anhydride) is used as the base polymer as it has the possibility to introduce non-covalent bonding sites through grafting reactions on the double bonds or on maleic anhydride groups. The free amine group present in the main compound was grafted onto the backbone of poly (butadiene-co-maleic anhydride) via reaction of amine with maleic anhydride group. The main design of supramolecular self-assembly within poly (butadiene-co-maleic anhydride) with a suitable counterpart poly (butadiene-co-maleimide), is prepared and used in this thesis. The miscibility of the two polymers is proven by the presence of a single Tg in the DSC results of the mixture and also by the formation of homogeneous films with no phase separation in AFM. However the formation of hydrogen bonding within the monomer was proven by 1H NMR, IR studies. Further formation of complex between two polymers was established from the results of viscosity. Also the interactions between the complexes exert a distinct influence on the rheological behavior of the blend. Lastly the reversibility of this supramolecular blend was assured by temperature dependent viscosity values. In the final part of this work, bromobutyl rubber (BIIR) is selected as the model elastomer which has vast application in the tire industry; as the inner-liner that holds the air in the tire and also used as rubber stoppers for sealing medicine vials and bottles The bromine functionality can be substituted with an amine group making it more susceptible towards the incorporation of different organic moieties. In this way, the derivative of 2,6-diaminopyridine having a pendant amine group is incorporated in BIIR. As a counterpart uracil is used as its H-bond forming ability with diaminopyridine moieties is well established and supported by different previous research works. The supramolecular network formed between these two monomers help to generate self-healing effects within BIIR rubber. Fig. 2 represents the supramolecular network formed between chains of BIIR. The self-healing effect of the rubber material is examined through the stress-strain experiments where up to 82% healing was observed when heated up to 70 °C. With increasing temperature better healing was observed whereas at room temperature a 40% healing tendency was noticed. It is also interesting to note that the thermal and dynamic mechanical properties of this tailor made self-healing BIIR is identical with sulphur cured conventional BIIR.

No description available.

It is widely accepted that the sharing of electrons constitutes a bond. Conversely, molecular interactions that do not involve electron transfer, such as van der Waals forces and electrostatics are defined as "non-bonding" or "non-covalent" interactions. More recently computational and experimental observations have shown situations where the division between "bonding" and "non-bonding" interactions is blurred. One such class of interactions are known as σ-hole interactions. Chapter 1 provides a literature review of investigations into the nature of σ-hole interactions, highlighting the individual contributing factors. Chapter 2 provides a detailed analysis into the nature of chalcogen-bonding interactions. Synthetic molecular balances are employed for experimental measurements of conformational free energies in different solvents, facilitating a detailed examination of the energetics and associated solvent and substituent effects on chalcogen-bonding interactions. The chalcogen-bonding interactions examined were found to have surprisingly little solvent dependence. The independence of the conformational free energies on solvent polarity, polarisability and H-bond characteristics showed that electrostatic, solvophobic or dispersion forces were not dominant factors in accounting for the experimentally observed trends. A molecular orbital analysis provided a quantitative relationship between the experimental free energies and the molecular orbital energies, which was consistent with chalcogen-bonding interactions being dominated by an n→σ* orbital delocalisation. Chapters 3 and 4 both use the molecular orbital modelling approach established in Chapter 2 to investigate the potential partial covalency in H-bonding and carbonyl···carbonyl interactions. H-bonding is generally considered to be an electrostatically dominated interaction. However, computational results have suggested a partial covalent character in H-bonding. The molecular orbital analysis revealed an n→σ* electron delocalisation in all H-bonding systems evaluated. However, no quantitative correlation could be found with experimental free energies. Similarly, the nature of carbonyl···carbonyl interactions has been subject to debate, with electrostatic or an n→π* electron delocalisation having been proposed as the dominant factors. The molecular orbital analysis employed here showed that n→π* delocalisation was exceptionally geometry dependent. Studies of literature systems reveal that n→π* delocalisation contributes to overall stability of a range of systems, with a quantitative link between molecular orbital energy and conformational free energies.

PTMO-urethane and urea diacrylates (UtDA, UrDA) were synthesized from a two-step reactions of bis (4-isocyanatocyclohexyl) methane (HMDI) with either α,Ï -hydroxy-terminated poly (tetramethylene oxide) (PTMO Mn 250, 1000, 2000 and 2900 g/mol) or α,Ï -aminopropyl-terminated PTMO and 2-hydroxyethyl acrylate (HEA). PTMO-based ester precursors (EtDA) were also synthesized from α,Ï -hydroxy-terminated PTMO (Mn 1000 and 2000 g/mol). Two bis acetoacetates were synthesized from acetoacetylation of 1,4-butanediol and 250 g/mol hydroxy-terminated PTMO with tert-butyl acetoacetate. ¹H NMR spectroscopy confirmed the structure and average molecular weights (Mn)of diacrylates. Mn of these precursors were in the range of 950 to 3670 g/mol by ¹H NMR. The rheological properties of diacrylates were studied and activation energies for flow were calculated. Activation energies increased with increasing Mn and hydrogen-bond segment content. Michael carbon addition was employed to covalently crosslink the precursors resulting in networks with gel fractions better than 90%. DSC and DMA experiments revealed that networks had a broad distribution of glass transition temperatures depending on Mn and degree of hydrogen bonding present in the diacrylates. Their Tg's varied from -61 ºC to 63 ºC depending on the crosslinking density and hydrogen-bonding segment content. TGA revealed that UtDA and UrDA networks had an improved thermal stability compared to their EtDA counterparts. Tensile properties showed a variation depending on the structure and Mn of diacrylate and BisAcAc precursors. The storage moduli of networks precursor change from 25.3 MPa to 2.0 MPa with increasing Mn of the urethane diacrylate Elongation at break increased from 255% to 755 % for the same networks. The Young's moduli increased from 3.27 MPa for EtDA 2000 to 311.1 MPa for UrDA 2000 which was attributed to increasing degree of hydrogen-bonding. Acid functionalization of C70 P Baytubes multiwalled carbon nanotubes (MWCNT) generated acid-functionalized nanotubes (MWCNT-COOH). Suspension of MWCNT-COOH in organic solvents (chloroform, toluene, THF, DMF and 2-propanol) were prepared. DLS indicated average particle diameters of MWCNT-COOH in DMF and in 2-propanol were 139 nm and 162 nm respectively. FESEM of suspensions revealed aggregate free dispersion of MWCNT-COOH in DMF and 2-propanol. MWCNT-COOH containing composite networks were prepared. FESEM images of fracture surfaces of UtDA showed MWCNT-COOH were well-dispersed in the composites. DMA showed an increase in the rubbery plateau modulus which correlated with the MWCNT-COOH content in the networks. Tensile testing also revealed a relationship between MWCNT-COOH content and young's moduli and strain at break of networks. Storage moduli of networks increased from 25 MPa to 211 MPa with increasing MWCNT-COOH content whereas elongation at break decreased from 255 % to 146 %. UtDAs and pentaerythritol tetraacrylate (PETA) were crosslinked under UV radiation (6 passes, 1.42 ± 0.05 W.cm2 for each pass) in the presence of 2,2-dimethoxy-2-phenylacetophenone (DMPA) (1 wt. % of the mixture) UV initiator. DMA demonstrated the presence of broad glass transition regions with a range of Tg's which varied from -60 °C to -30°C. Tensile testing also revealed the relationship between Young's moduli, strain at break and the molecular weight of the diacrylates. The increasing molecular weight of urethane diacrylate precursors caused a drop in the storage moduli of networks from 15.8 MPa to 1.4 MPa and an increase in elongation at break from 76 % to 132 %. / Master of Science

Les silicones auto-cicatrisants de façon autonome (sans stimulus externe) présentent de faibles propriétés mécaniques, limitant leur utilisation industrielle. L’objectif de cette étude était de dépasser cette limitation. Nos travaux se sont intéressés aux copolymères segmentés PDMS-urée constitués de blocs souples (SS) et rigides (HS). Tout d’abord, nous avons étudié la relation entre la structure des bis-urées et les propriétés macroscopiques. Nous avons ainsi montré que la symétrie des HS gouverne la rigidité de ces matériaux. Toutefois, la présence de HS symétriques inhibe la cicatrisation du matériau. Puis, nous avons développé un nouveau concept permettant d’accélérer leur cinétique de cicatrisation. Un stoppeur de chaine macromoléculaire a été ajouté à la formulation de ces silicones thermoplastiques, créant un défaut dans l’assemblage supramoléculaire, conduisant à des clusters organiques plus petits et plus dynamiques. Néanmoins, contrairement aux plastifiants, la chute du module de Young observée par rapport à la matrice est limitée. D’ailleurs, nous reportons la synthèse d’un copolymère PDMS-urée avec un module de traction de 1MPa dont 90% de la contrainte à rupture peut être récupérée après cicatrisation pendant 24h à 25°C. Ce concept a aussi été adapté à un thermoplastique commercial (GENIOMER80). Enfin, notre défi a été d’optimiser la balance entre rigidité et autocicatrisation. Dans ce contexte, nous avons synthétisé de nouvelles matrices plus rigides, ainsi que des additifs avec des groupements associatifs de plus grande énergie cohésive. Nous avons alors pu repousser la limite de rigidité accessible aux silicones auto-cicatrisants de façon autonome (3MPa). / Autonomous self-healable (without external stimulus) silicones exhibit too low mechanical properties restricting their use in industry. The aim of this study was to overcome this limitation. We focused our work on segmented PDMS-urea copolymers made of soft (SS) and hard segments (HS). First the investigation of the relationship between the bis-urea chemical structure and the macroscopic properties was made. Results shown that, the symmetry of HS governs materials rigidity. Moreover, with a too symmetrical HS, the material does not exhibit self-healing abilities. We have developed a new concept improving the healing efficiency of these materials. The idea was to add to the formulation of these silicone thermoplastics a macromolecular chain stopper. The new additive creates a defect in the supramolecular assembly which leads to smaller and more dynamic H-bonding clusters and hence a faster healing kinetic. Unlike plasticizers, this additive deteriorates the tensile modulus only marginally. We therefore report a stress at break recovery of 90% after 24 hours at room temperature for a PDMS-urea copolymer with a tensile modulus of 1MPa. The concept was also extented to a commercial thermoplastic (GENIOMER80). Finally, our last challenge was to manage the balance between rigidity and chains dynamics allowing self-healable materials with good mechanical properties. In this context we have synthesized new matrixes with higher HS percentage and additives with stickers with higher cohesive energy. These new syntheses have led to an improvement of the rigidity limit reachable by the autonomous self-healable silicones (3MPa).

This thesis contains investigations in two different areas, described under six chapters. Chapter 1 contains a broad introduction to the area of foldamers, while Chapters 2, 3, 4, and 5 deal with various novel classes of synthetic polymers which can form folded structures in solution utilizing different non-covalent interactions. Chapter 6 deals with a distinctly different topic, where the objective was to study the effect of phenyl ring location on the micellization properties of a series of isomeric cationic surfactants. Synthetic polymers typically adopt a random coil conformation in solution, which is primarily an entropy driven process. So the generation of well-defined secondary structures in synthetic polymers requires specific intra-chain inter-segment interactions that will give adequate enthalpic contribution to overcome the entropic penalty associated with the formation of well-ordered conformations. During the past decade, various research groups have made significant effort to understand the essential design elements that could enable secondary structure formation in synthetic macromolecules through intra-chain inter-segment interactions, such as hydrogen bonding, solvophobic and solvophilic interaction, acid-base interaction, bond angle constraint, steric interaction, charge-transfer interaction, metal-ion complexation etc.1 Gellman2 first used the term “foldamer” to describe “any polymer with a strong tendency to adopt a specific compact conformation” which was more precisely defined by Moore and coworkers3 as “any oligomer that folds into a conformationally ordered state in solution, the structures of which are stabilized by a collection of non-covalent interactions between nonadjacent monomer units” and where the folded conformation is one of the various possible conformations. Several classes of foldamers have been studied during the past decade; a majority of them are well-defined oligomers that possess relatively restricted conformational degrees of freedom. Relatively fewer studies have explored conformational control in flexible high molecular weight polymers that possess greater conformational freedom.4 A few years ago, Ghosh et al. designed a polymeric system wherein charge-transfer interactions between alternatively placed electron-rich and electron-deficient aromatic units, aided by metal-ion complexation and solvophobic interactions, causes the polymer chain to adopt a specific folded conformation.5 Such charge-transfer induced folding was first studied by Iverson and co-workers6 in well-defined oligomers and was later elaborated by Zhao et al.7 to generate alternate designs to fold oligomeric systems. In all these studies, the C-T interactions served not only to assist the folding process but it also served as a valuable spectroscopic signature to study the folding process. The objectives of the present study are to develop simple synthetic strategies to generate different types of polymers that could be fold in solution using various noncovalent interactions. We have developed a simple synthetic strategy to design a new type of donor (1,5-dialkoxynaphthalene-DAN) containing polymer that carries a tertiary amine unit in the spacer segment, which could interact strongly with a suitably designed acceptor (pyromellitic diimide-PDI) bearing folding agent that carries a carboxylic acid group, as shown in Scheme 1.8 This acid-base interaction, brings the acceptor unit in a suitable position so as to form a C-T complex with the adjacent donors, resulting in the folding of the polymer chain. The folded conformation was studied using UV-vis and NMR spectroscopy and the folding propensities were rationalized using DFT studies. The highest association constant between the folding agent and the polymer was estimated to be around 1200 M-1. Scheme 1. Schematic representation of folding aided by two-point interactions with a folding agent. This value of association constant was not adequate to realize some potentially interesting properties in solid state. In an attempt to develop alternate systems, that could exhibit stronger propensity to fold, we designed a new type of cationic ionene,9 wherein electron-rich (DAN) and electron-deficient (PDI) aromatic units were included within the alkylene segments in an alternating fashion, as shown in Scheme 2.10 The charge-transfer (C-T) interaction between the donor and acceptor units in neighbouring segments of the ionene not only reinforced the transition to the collapsed nano-bundle form but also provides a useful spectroscopic handle to monitor the conformational change. The UV-visible spectra of these novel D-A ionene solutions at a fixed concentration in four different solvents, namely water, methanol, acetonitrile and DMSO, show different extents of charge-transfer interaction. The colour of the solution in water was deep-red, whereas in acetonitrile, it was light-yellow. The conformational transition could also be induced by titrating an acetonitrile solution of the ionene with increasing amounts of water causing a dramatic increase in the intensity of the charge-transfer band, which reflects the extent of collapse to the zig-zag state that brings the donor and acceptor units together. AFM studies confirmed the presence of flat pancake-like aggregates having nearly constant height of about 3-5 nm, which was in accordance with the estimated thickness of the postulated zig-zag structure. Scheme 2. Schematic depiction of folding of D-A ionene (left), AFM micrograph showing pancake-like aggregates of D-A ionenes (right-top), a line scan depicting the heights and diameters of the aggregates along with a schematic depiction of the aggregate (right-bottom). Scheme 3. Schematic representation of folding aided by interactions with a folding agent. In order to explore this concept further, we designed a two component system wherein the solvophobically-driven collapse of a DAN-containing ionene chain in a polar solvent is reinforced by intercalation with a suitably designed electron-deficient acceptor-containing external folding agent. DAN containing ionene polymer chains in polar solvent form an accordion-type zig-zag structure that brings adjacent donor units in close proximity; this provided an ideal hydrophobic pocket for intercalation of suitably designed electron-deficient acceptor molecules, the additional driving motivation for the intercalation being the formation of a C-T complex as shown in Scheme 3.11 Several acceptor-bearing molecules were prepared by the derivatization of pyromellitic dianhydride and naphthalene tetracarboxylic dianhydride with two different oligoethylene glycol monomethyl ether monoamines. UV-vis spectroscopic studies were carried out by using a 1:1 mixture of the DAN-ionenes and different acceptor molecules in water/DMSO solvent mixtures. The intensity of the charge-transfer (C-T) band was seen to increase with the water content in the solvent mixture, thereby suggesting that the intercalation is indeed aided by solvophobic effects. The naphthalene diimide (NDI) bearing acceptor molecules consistently formed significantly stronger C-T complexes when compared to the pyromellitic diimide (PDI) bearing acceptor molecules, which is a reflection of the stronger π-stacking tendency of the former. The highest association constant between the folding agent and the polymer was estimated to be around 4519 M-1, which was a substantial improvement over the earlier reported values.9 With a slight modification in the pendant group, we designed a water-soluble DAN-containing ionene, which can intercalate hydrophobic electron-deficient molecules, like TNT (2,4,6-trinitrotoluene), within the hydrophobic interstices between DAN units (as shown in Scheme 4), causing a depletion in fluorescence from the DAN units; TNT at concentration as low as 30 nM could be detected in this manner. Scheme 4. Schematic representation of folding of water soluble ionene and interactions with an electron-deficient hydrophobic moiety TNT. Scheme 5. Schematic representation of folded D-A allyl ionene. In light of the growing interest in single-chain polymeric nanoparticles, the fully collapsed D-A ionenes in water could be viewed as polymeric nanoparticles that are stitched together by reversible weak noncovalent interactions. In an attempt to transform the folded structure into a polymeric nanoparticle using covalent bonding, we designed D-A ionene that carries potentially polymerizable allyl units on the cationic head group instead of the dimethyl amine head group that was used in previous examples (as shown in Scheme 5). Preliminary studies showed that polymerization does not proceed readily; however, thiol-ene based clicking strategy enabled partial stitching of the folded segments, by the use of a suitably designed dithiol. In the last section of this thesis, we examined the effect of phenyl ring location on the micellization properties of a series of isomeric cationic surfactants, wherein the phenyl ring location was varied from head to tail region (as shown in Scheme 6).12 Thus, cationic surfactants (S1-S5) bearing a long alkyl chain that carries a 1,4phenylene unit and a trimethyl ammonium headgroup was synthesized and their solution properties were examined. Micellization behavior was studied using conductivity, ITC (Isothermal Titration Calorimetry), SANS (Small-Angle Neutron Scattering) and NMR. These present studies demonstrated that the presence of a large rigid ring near the hydrocarbon tail-end of the surfactant leads to a dramatic change in the micelle structure; the driving motivation to form micelles in such systems is greatly reduced and the micelles that are formed are relatively smaller and contain significantly fewer surfactants. NMR studies of micellar solutions of these surfactants indicate that the variation in the phenyl ring location may also help to probe the microenvironment at various depths within the micellar aggregates. Scheme 6. Structures of the various surfactant molecules carrying the 1,4-dioxyphenylene unit at different locations within hydrophobic segment (left), variation of CMC values (right). References (1) Foldamers - structure, properties, and applications, edited by Stefan Hecht and Ivan Huc, Wiley-VCH, 2007. (2) Gellman, S. H. Acc. Chem. Res. 1998, 31, 173. (3) Hill, D. J.; Mio, M. J.; Prince, R. B.; Huges, T. S.; Moore, J. S. Chem. Rev. 2001, 101, 3893. (4) (a) Wang, W.; Li, L. S.; Helms, G.; Zhou, H. H.; Li, A. D. Q. J. Am. Chem. Soc. 2003, 125, 1120. (b) Li, A. D. Q.; Wang, W.; Wang, L. Q. Chem. Eur. J. 2003, 9, 4594. (c) Neuteboom, E. E.; Meskers, S. C. J.; Meijer, E. W.; Janssen, R. A. J. Macromol. Chem. Phys. 2004, 205, 217. (d) Balbo Block, M. A.; Hecht, S. Macromolecules 2004, 37, 4761. (5) (a) Ghosh, S.; Ramakrishnan, S. Angew. Chem. Int. Ed. 2004, 43, 3264. (b) Ghosh, S.; Ramakrishnan, S. Angew. Chem. Int. Ed. 2005, 44, 5441. (6) Lokey, R. S.; Iverson, B. L. Nature 1995, 375, 303. (7) Zhao, X.; Jia, M. X. Jiang, X. K.; Wu, L. Z.; Li, Z. T.; Chen. G. J. J. Org. Chem. 2004, 69, 270. (8) De, S.; Koley, D.; Ramakrishnan, S. Macromolecules 2010, 43, 3183. (9) Williams, S. R.; Long, T. E. Prog. Polym. Sci. 2009, 34, 762. (10) De, S.; Ramakrishnan, S. Macromolecules 2009, 42, 8599. (11) De, S.; Ramakrishnan, S. Chem. Asian J. 2011, 6, 149. (12) De, S.; Aswal, V. K.; Ramakrishnan, S. Langmuir 2010, 26, 17882. (For structural formula pl see the abstract file.

No description available.