Modified Carbonyl Iron Powders to Have Partial Interface Bonding for Stretchable Polymer Matrix Composites

With the technological progress of wearable electronics operated in 5G network communication system, a stretchable noise suppressor at GHz bandwidth that is reliable under severe deformation coming from the user’s motion should be developed. However, current material systems for the noise suppressor showed a limited stretchability. In this study, the CIP/PDMS composite with partial interface bonding between particle and polymer matrix was introduced as a solution to enhance the stretchability dramatically. Modulation of surface condition of CIPs to have the partial interface bonding (CIP-PID) provided the large freedom for PDMS matrix in a composite to elongate similarly to the pure PDMS. The CIP-PID based composites showed an ultra large strain of ~165% even at the 40 vol% of CIP-PIDs, while only ~75% of strain was observed for CIPs with the full interface bonding (CIP-FID) at the same particle contents. Microstructural analysis of the strained composites and FEM simulation revealed that PDMS matrix partially bonded to CIPs formed the free surface that can be deformed as pure PDMS, thereby resulting in the similar stretchability to those of pure PDMS even in the form of composites. Moreover, CIP-PID based composites showed a proper disperionability and high noise suppressing efficiencty, which are comparable to those of CIP-FIDs. Our work provides ways to the increase in stretchability of polymer-based composite films with a proper noise suppressing efficiency at GHz bandwidth in application to the next generation wearable devices requiring massive data communication.