Additive‐Assisted Modification of PDMS Nanocomposites: Rheology, Reinforcement Mechanisms, and Multifunctional Performance

ABSTRACT Polydimethylsiloxane (PDMS) is a widely used elastomer owing to its flexibility, optical clarity, ease of processing, and biocompatibility. However, its application in high‐performance systems is often limited by poor mechanical strength, modest thermal endurance, and high gas permeability. Recent advances in additive‐assisted modification using carbon‐based, inorganic, and hybrid nanofillers have demonstrated significant improvements in rheological, mechanical, thermal, and functional performance. This review critically examines the influence of nanofillers on PDMS, focusing on reinforcement mechanisms, rheological behavior, and multifunctional properties. The mechanisms governing property improvements, such as filler–matrix interactions, interfacial bonding, dispersion quality, and surface functionalization, are analyzed in detail. Comparisons are drawn among carbon‐based materials, inorganic fillers, and hybrid systems to provide a comprehensive understanding of structure–property relationships. Applications in microfluidics, flexible electronics, biomedical systems, and protective coatings are also highlighted. Finally, current challenges related to dispersion, large‐scale processing, and biocompatibility are discussed, together with future opportunities in hybrid reinforcement, sustainable additives, and data‐driven materials design for next‐generation PDMS technologies.