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Effect of the Linking Structure of Nonlinear Optical Side Groups on the Phase Behavior of an Aromatic Polyester Backbone

  1. Maeng-Eun Lee1,
  2. Seayeal Seong1,
  3. Kyoung-Tai No1,
  4. O-Pil Kwon2,
  5. Suck-Hyun Lee2,*

Article first published online: 29 MAR 2004

DOI: 10.1002/mats.200300016

Issue

Macromolecular Theory and Simulations

Macromolecular Theory and Simulations

Volume 13, Issue 3, pages 265–272, April 2004

Additional Information

How to Cite

Lee, M.-E., Seong, S., No, K.-T., Kwon, O.-P. and Lee, S.-H. (2004), Effect of the Linking Structure of Nonlinear Optical Side Groups on the Phase Behavior of an Aromatic Polyester Backbone. Macromol. Theory Simul., 13: 265–272. doi: 10.1002/mats.200300016

Author Information

  1. 1

    Hyperstructured Organic Materials Research Center (HOMRC) at Seoul National University, Computer Aided Molecular Design Research Center and Department of Chemistry, Soong Sil University, Seoul 156-743, Korea

  2. 2

    Hyperstructured Organic Materials Research Center (HOMRC) at Seoul National University, Department of Molecular Science and Technology, Ajou University, Suwon, 442-749, Korea

*Hyperstructured Organic Materials Research Center (HOMRC) at Seoul National University, Department of Molecular Science and Technology, Ajou University, Suwon, 442-749, Korea. Fax: 0082 31 2191612

Publication History

  1. Issue published online: 29 MAR 2004
  2. Article first published online: 29 MAR 2004
  3. Manuscript Accepted: 21 NOV 2003
  4. Manuscript Revised: 31 OCT 2003
  5. Manuscript Received: 22 AUG 2003

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Keywords:

  • liquid crystalline polymers (LCP);
  • molecular dynamics;
  • NLO;
  • phase behavior;
  • polyesters

Abstract

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Summary: The phase behavior of poly(p-phenylene terephthalate)s (PPT) with pendant side groups, N-(4-nitrophenyl)ethylaminoethanol (NPE) and N-(4-nitrophenyl)-L-prolinol (NPP) has been studied by using differential scanning calorimetry (DSC), wide-angle X-ray scattering (WAXS), and second harmonic generation (SHG). PPT-NPE showed a layered liquid crystalline morphology while PPT-NPP showed a completely amorphous structure. Compressive or shear stress applied on the polymer melt surface at 210 °C induced a more prominent layered structure of PPT-NPE whereas the amorphous structure of PPT-NPP remained unchanged under the stress. In order to understand this phase difference in terms of the repeat structure, we attempted theoretical ab initio Hartree-Fock, and DFT calculations for the monomers and molecular dynamics for the bulk state. The results indicated that molecular configurations are a good way of microscopically understanding the phases of rigid backbone polymers with functional side groups: The NPT (constant particle number, pressure, and temperature) simulation data at 210 °C agree qualitatively with the experimental data and the difference between PPT-NPE and PPT-NPP could be understood using rotational energy barrier, steric hindrance and inter-chain interactions. X-ray diffractometer (XRD) simulation patterns for the oligomers are also in qualitative agreement with the experimental WAXS data and the structural parameters of stacks of PPT-NPE chains are estimated to be layer distance (4.6 Å), backbone distance (21.5 Å), and side distance (12 Å).

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