Work

Porous polymer films with tunable refractive index

Year: 2025

Type: article

Abstract: . A simple, energy efficient, and cost-effective method is presented for the fabrication of polymeric films with a low refractive index in the visible spectral range, suitable as insulators in flexible optical and optoelectronic devices. Thin films based on a commercial polymer with high thermal stability (up to 200°C), such as poly(2,6-dimethyl-1,4-phenylene)oxide (PPO), presenting both microporosity in the nanoporous crystalline (NC) phases as well as a tunable macroporosity in the amorphous phase, have been prepared and characterized by several techniques. Refractive index of PPO thin films in the visible spectral range, as measured by spectroscopic ellipsometry, varies from a maximum of 1.58 (at 560 nm) for fully amorphous samples to a minimum of 1.39 for NC films exhibiting both micro- and macroporosity. This latter value is close to that of polytetrafluoroethylene (PTFE), one of the polymers exhibiting the lowest refractive index value, and has been obtained through a straightforward, very easy and low energy consuming process.

Source: Polymer

DOI: 10.1016/j.polymer.2025.128820

Authors: I. Lameri, D. Riccardi, S. Syed, G. Viscusi, A. Sassella, P. Rizzo

Institutions: University of Milano-Bicocca, University of Salerno, National Interuniversity Consortium of Materials Science and Technology

Language: English

Topic: Synthesis and properties of polymers

Subfield: Polymers and Plastics

Field: Materials Science

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,980

Funders: European Commission, Ministero dell’Istruzione, dell’Università e della Ricerca, Ministero dell'Università e della Ricerca