Pendant group polymers

Y.-H. Kim, J.-H. Ahn, D.-C. Shin, and S.-K. Kwon, Synthesis and characterization of poly (terphenylenevinylene) derivatives containing alkoxy substituents and (or) phenyl pendant group, Polymer, 45 2525-2532, 2004. 

V i O.leV for motion along the polymeric backbone of pendant group polymers, and otherwise V << O.leV (1, 8). Therefore inequality (3) is clearly satisfied for these materials, so injected charges form intrinsic (pendant-group polymers) or extrinsic (molecular-ly-doped polymers) local molecular-ion states (j, 2, 7> 8) A similar situation seems to prevail for molecular glasses, although the parameter values are not yet firmly established in this case. For bulk molecular crystals in the absence of defects... 

I proceed by first describing in Sec. II the construction of a molecular-orbital model suitable for interpreting molecular FES and UVA spectra. Then, this model is extended to encompass intramolecular (Sec. Ill) and intermolecular (Sec. IV) relaxation. The paper concludes with an indication of the applications of the model to interpret FES and UVA from polyacetylene (11) and from two pendant-group polymers, polystyrene and poly(2-vinyl pyridine) (9, 10). 

Molecular-Ion States in Aromatic Pendant Group Polymers... 

In the examples of our work on organic molecular and polymeric solids that follow, first some contributions to the UPS line widths in condensed molecular solids are discussed for two prototype systems, anthracene and isopropyl benzene then the UPS of two.aromatic pendant group polymers, polystyrene and poly(2-vinyl pyridine), are discussed and compared with some spectra concerning the simplest linear conjugated polymer, polyacetylene. 

Relaxation Energy Shifts and Localized Molecular-Ion States in Aromatic Pendant Group Polymers. The electronic structure of polystyrene (PS) and poly vinyl pyridine (PVP) have been studied using a variety of electronic spectroscopies and model calculations (W). Here, we review the results of the UPS and ultra violet absorption spectroscopy (UAS) portion of that study, and discuss the results in a phenomenological manner. The aim of this... 

We summarize here the features of the UPS and UVA data which lead to the molecular ion concept for these aromatic pendant group polymers. First, the spectra of the polymers PVP and PS are essentially identical to those of condensed model molecular moieties 2-vinyl pyridine and ethyl benzene, respectively. Second, the solid-state spectra are related to the gas-phase spectra of these model moieties by an essentially constant shift to higher energy (lower binding energy) of all the ionization peaks by = 1.5 0.1 eV. Third, the width in energy of the solid-state ionization peak is Air = 1.0 0.1 for both polymers... 

The magnitude of the intermolecular relaxation energy shifts in the solid phase UPS spectra of the polymer films relative to the gas phase UPS spectra of the model molecules seen for the aromatic pendant group polymers is also observed in the case of the (CH) versus ethylene UPS spectra, as can be seen in Fig. 9. 

Intermolecular relaxation effects are a central issue in the interpretation of the ultraviolet photoelectron spectroscopy (UPS) of molecular solids. These relaxation effects result in several significant characteristics of UPS valence spectra, intermolecular relaxation phenomena lead to localized electron molecular-ion states, which are responsible for rigid gas-to-solid molecular spectral energy shifts, spectral line broadening, and dynamic electronic localization effects in aromatic pendant group polymers. 

FIGURE 1.10 Comparison of the emission spectra for PPE with cyclophane pendant group (polymer in Fig. 1.9) in solution, as a highly aligned LB film (two layers) and as spin-cast from CHC13. The excitation wavelength was 420nm. (Source Ref. [18].)... 

Gill, R. Muzhar, M. Siddiq, M., Structural Characterization and Thermal Behaviour of Block Copolymers of Polydimeth sdoxane and Polyamide Having Trichlorogermyl Pendant Groups. Polym. Int. 2010,59,1598-1605. 

Y. Liu, Y. Zhang, S. Guan, L. Li, Z. Jiang, Synthesis and properties of soluble fluorinated poly(ether imide)s with different pendant groups. Polymer 49 (25) (2008) 5439-5445. 

C.-Y. Wang, H.-P. Zhao, G. Li, J.-M. Jiang, Novel fluorinated polyimides derived from an unsymmetrical diamine containing trifluo-romethyl and methyl pendant groups, Polym. Adv. Technol. 22 (12) (2011) 1816-1823. 

Katsumata T, Shiotsuki M, Sanda F, Masuda T (2009) Synthesis and properties of polynorbomenes bearing oligomeric siloxane pendant groups. Polymer 50 1389-1394... 

C. B. Duke, W. R. Salaneck, T. J. Fabish, J. J. Rit-sko, H, R. Thomas, and A. Paton, The electronic structure of pendant-group polymers molecular ion states and dielectric properties of poly(2-vinyl pyridine), Phys. Rev. BI8 57 7 (1978). 

The introduction of localized defect states by injected charges is not peculiar to polyacetylene. Rather, it is a general feature of certain amorphous semiconductors (35). Indeed, amorphous semiconductors may be divided into two broad classes disorder dominated and defect dominated. Pendant-group polymers... 

Alvarez-Gallego, Y., Ruflinann, B., Silva, V., Silva, H., Lozano, A. E., Campa, J. G., Nunes, S. P., Abajo, J., Sulfonated polynaphthalimides with benzimidazole pendant groups. Polymer, 2008, 49, 3875-3883. 

This paper is devoted to the presentation of a brief overview of a recently-developed "relaxation-localization" model of localized molecular-ion and exciton states in polymers and molecular glasses. This model was proposed initially to interpret photoemission measurements from two pgn ant-group polymers polystyrene and p ly(2-vinyl pyridine.) It ext was utilized in the prediction and subsequent observation of surface states of molecular solids as well as of the temperature dependence of photoe iss on and UV absorption linewidths of molecular films. Having proven successful in describing the spectroscopic properties of typical pendant-group polymers and molecular glasses, the model most recently has been extended to provide a description of electron-transfer processes in both these materials and molecularly-doped polymers. Therefore it affords a unified and experimentally-verified microscopic description of electron ionization, excitation and transfer processes in a variety of molecular and polymeric materials. 

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