Abstract
Polymers that alter their properties and functions in response to carbon dioxide (CO(2)) exposure offer significant potential for the development of smart technologies and innovative CO(2) utilization approaches. Nonetheless, effectively regulating the behavior of solid-state polymers using CO(2) remains a considerable challenge, highlighting the need for robust and reliable strategies to address this issue. This study presents elastomers that feature nanophase-separated morphologies composed of CO(2)-vitrifiable polyethyleneimine and CO(2)-permeable polydimethylsiloxane components. The elastomers (Young's modulus (E) of approximately 1 MPa) reversibly transform into hard plastics (E > 2 GPa) in the presence of CO(2). In addition to bulk stiffening, their surface adhesion and friction rapidly shift, and the material's fluorescence is significantly amplified. Here, we show that these multifunctional responses to CO(2) position the materials as innovative platforms for responsive mechanical systems and CO(2)-activated optical devices, with potential applications in sensing, display, and data storage technologies.