Title: Ultralow stress, thermally stable cross-linked polymer films of polydivinylbenzene (PDVB)

Abstract

Although closely related to polystyrene, poly(divinylbenzene) (PDVB) has found limited utility due to the difficulties associated with its synthesis. As a highly cross-linked polymer, PDVB is infusible and insoluble and thus nearly impossible to shape into films by either melt or solvent-based processes. Here, we report the initiated chemical vapor deposition (iCVD) of nearly stress-free, highly transparent, free-standing films of PDVB up to 25 μm thick. Films initially grow under tensile intrinsic stress but become more compressive with thickness and eventually converge to zero-stress values once they reach ≥10 μm in thickness. Upon initial heating, the evaporative loss of unreacted monomer left in the polymer matrix induces between 35 and 45 MPa of tensile stress in the films. Afterward, subsequent heating cycles induce reversible stress and film expansion behaviors. We estimate the degree of cross-linking to be 44%, resulting in high thermal stability (up to 300 °C) and mechanical stiffness (Young’s modulus of 5.2 GPa). As a result, the low stress combined with high cross-linking makes iCVD PDVB an excellent candidate for protective coatings in harsh environments.

Authors:

Lepro, Xavier  ^[1];

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Ehrmann, Paul ^[1]; Menapace, Joseph ^[1]; Lotscher, Johann ^[1]; Shin, Swanee ^[1]; Meissner, Richard ^[1]; Baxamusa, Salmaan ^[1]

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+ Show Author Affiliations

1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Publication Date:

Wed May 10 00:00:00 EDT 2017

Research Org.:

Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1364741

Report Number(s):

LLNL-JRNL-710659
Journal ID: ISSN 0743-7463

Grant/Contract Number:  

AC52-07NA27344

Resource Type:

Accepted Manuscript

Journal Name:

Langmuir

Additional Journal Information:

Journal Volume: 33; Journal Issue: 21; Journal ID: ISSN 0743-7463

Publisher:

American Chemical Society

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE