As
a fundamental structure characteristic in polymers, fractional
free volume (FFV) plays an indispensable role in governing polymer
properties and performance. However, the design of new high-FFV polymers
is challenging. In this study, we report a data-driven approach and
aim to accelerate the discovery of high-FFV polymers. First, a computational
method is proposed to calculate FFV, and a two-step fragmentation
method is developed to construct a fragment library for digital representation
of polymer structures. Data mining is employed to identify promising
fragments for high FFV. Subsequently, machine learning (ML) models
are trained using a data set with 1683 polymers and their excellent
transferability is demonstrated by out-of-sample predictions in another
data set with 11,479 polymers. Finally, the ML models are used to
screen ∼1 million hypothetical polymers, and 29,482 polymers
with FFV > 0.2 are shortlisted; representative high-FFV polymers
are
validated by molecular simulations, and design strategies are highlighted.
To further facilitate the discovery of new high-FFV polymers, we develop
an online interactive platform , which allows for rapid FFV predictions, given polymer structures.
The data-driven approach in this study might advance the development
of new high-FFV polymers and further explore quantitative structure–property
relationships for polymers.