In:
Macromolecular Materials and Engineering, Wiley, Vol. 306, No. 3 ( 2021-03)
Abstract:
Due to the development of dynamic flexible organic light‐emitting diode displays, colorless polyimides (CPI) as the supporting or protecting optical films, are facing significant challenges due to the requirements of optical, mechanical, thermal, and chemical properties. Typical CPIs are derived from TFDB (2,2‐bis(trifluoro‐methyl)‐4,4′‐diaminobiphenyl)/6FDA (4,4′‐(hexafluoroisopropylidene)diphthalic anhydride), which still need to be improved in both dimensional stability and optical performance. In this communication, a strong electron acceptor group, the sulfoxide bond, is first introduced into the TFDB block of CPI chains. Based on this introduction, the distribution of the electron cloud in the polymer chain is reconstructed under the strongly pulling electron effect, and the spatial conformation of the polymer chain is also affected by the rigid and twisted sulfoxide group. The influences on CPI's optical properties, especially the refractive index and the retardation, are studied and discussed in detail by experimental results and theoretical calculations. It is shown that the CPI with the sulfoxide group exhibits higher optical transparency, lower yellow index, phase retardation and coefficient of thermal expansion, which is an ideal material for CPI optical films.
Type of Medium:
Online Resource
ISSN:
1438-7492
,
1439-2054
DOI:
10.1002/mame.202000606
Language:
English
Publisher:
Wiley
Publication Date:
2021
detail.hit.zdb_id:
2004372-7
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