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Cross-Linkable Spirobisindane-Based Polyimides with
Enhanced Low-Dielectric Properties for High-Frequency Applications
Seonyoung Jo (1699684)
Chaeyeon Park (21753786)
No Kyun Park (19681773)
Seong Hun Choi (22697740)
Min Ki Choi (23097826)
Jaegi Lee (1614520)
Youngsu Jeong (25138634)
Eun-Ae Chu (25138637)
Yun Ho Kim (1486966)
Jong Chan Won (2323357)
Biophysics
Biochemistry
Space Science
Physical Sciences not elsewhere classified
Physiology
Biotechnology
Chemical Sciences not elsewhere classified
Ecology
gel fraction measurements
dissipation factor (<
based molecular design
based bar coating
10 ghz ).
dielectric enhancement cannot
exhibited enhanced hydrophobicity
55 series exhibited
k </ sub
f </ sub
fractional free volume
1 </ sup
frequency applications cross
55 exhibited
frequency applications
based polyimides
>< sub
28 ghz
free volume
dielectric properties
dielectric materials
volume responses
local free
different free
thermal stability
successful introduction
results demonstrate
resulting films
readily fabricated
pronounced decrease
postpolymerization functionalization
polyimide films
molar ratio
linked counterparts
ir spectroscopy
h nmr
enhanced low
effective strategy
dependent reorganization
attributed solely
allyl groups
Cross-linkable
spirobisindane-based polyimides were synthesized
and investigated as low-dielectric materials for high-frequency applications.
The polymer composition was controlled by varying the molar ratio
of diamines, and allyl groups were introduced through postpolymerization
functionalization to enable subsequent thermal cross-linking. The
successful introduction and cross-linking of the allyl groups were
confirmed by <sup>1</sup>H NMR and FT-IR spectroscopy, together with
gel fraction measurements. The resulting films were readily fabricated
by solution-based bar coating and exhibited enhanced hydrophobicity
and thermal stability after cross-linking. Positron annihilation lifetime
spectroscopy (PALS) revealed a composition-dependent reorganization
of the local free-volume structure upon cross-linking, rather than
a uniform increase in free volume. In particular, the 55 series exhibited
a pronounced decrease in fractional free volume after cross-linking,
whereas the 73 series showed relatively minor changes. Despite these
different free-volume responses, the cross-linked X-BMDA films exhibited
improved dielectric properties compared with their uncross-linked
counterparts, indicating that the dielectric enhancement cannot be
attributed solely to an increase in free volume. X-BMDA-55 exhibited
the lowest dielectric constant (<i>D</i><sub>k</sub> = 2.20
at 28 GHz) and dissipation factor (<i>D</i><sub>f</sub> =
0.0063 at 10 GHz). These results demonstrate that the combination
of spirobisindane-based molecular design and post-cross-linking provides
an effective strategy for controlling local molecular structure and
achieving low dielectric properties in polyimide films.
2026-09-29T00:00:00Z
Text
Journal contribution
10.1021/acsapm.6c02331.s001
https://figshare.com/articles/journal_contribution/Cross-Linkable_Spirobisindane-Based_Polyimides_with_Enhanced_Low-Dielectric_Properties_for_High-Frequency_Applications/34027376
CC BY-NC 4.0