Issue 13, 2022

Novel, flexible, and transparent thin film polyimide aerogels with enhanced thermal insulation and high service temperature

Abstract

Due to their high service temperature, excellent thermal insulation, nanoporous morphology, and low dielectric constant, polyimide (PI) aerogels have the potential capability to be used in the next generation of microelectronic devices and flexible electronics. The main challenge, however, is controlling the shrinkage during the sol–gel process, and developing thin films with improved thermal insulation, reduced shrinkage and density, and controllable thickness while maintaining mechanical flexibility. Yet, the majority of previously reported PI aerogels were in the form of bulk monolithic, with a very limited number of studies on other configurations. In this study, thin film PI aerogels are developed via a doctor blade applicator. Through control of processing parameters, namely solution viscosity, casting speed and inter-blade spacing, thin film PI aerogels with controllable thickness and uniformity are fabricated. The PI aerogel network is formed through imidization of flexible 4,4′-oxydianiline (ODA) and biphenyl-tetracarboxylic acid dianhydride (BPDA) monomers. Replacing 50 mol% of the ODA with a more rigid 2,2′-dimethylbenzidine (DMBZ) in the oligomer backbone gives aerogels with improved strength, enhanced hydrophobicity and lower dielectric constant. 1,3,5-Benzenetricarbonyl trichloride (BTC) is used to create a cross-linked network with strong integrity. Compared to previously used cross-linkers (TAB, OAPS, or TAPP), BTC has a lower cost and is commercially available. Several characterization techniques were performed to examine the physical, chemical, thermal, mechanical, electrical, and optical properties of the fabricated aerogels. These highlighted the multifunctionality of the PI aerogels, combining outstanding mechanical flexibility (fully bendable and rollable), excellent strength (compression E = ∼1.9 MPa), ultralow thermal conductivity (27.5 mW m−1), lightweight (ρ = 0.089 g cm−3), superior service temperature (over 560 °C), ultralow dielectric constant (∼2.7), and excellent self-extinguishing behavior. As a potential application of the fabricated thin film PI aerogels, microelectronics packaging can be thus proposed.

Graphical abstract: Novel, flexible, and transparent thin film polyimide aerogels with enhanced thermal insulation and high service temperature

Supplementary files

Article information

Article type
Paper
Submitted
27 12 2021
Accepted
09 2 2022
First published
18 2 2022

J. Mater. Chem. C, 2022,10, 5088-5108

Novel, flexible, and transparent thin film polyimide aerogels with enhanced thermal insulation and high service temperature

O. A. Tafreshi, S. Ghaffari-Mosanenzadeh, S. Karamikamkar, Z. Saadatnia, S. Kiddell, C. B. Park and H. E. Naguib, J. Mater. Chem. C, 2022, 10, 5088 DOI: 10.1039/D1TC06122D

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements