Tunable physicochemical properties of PDMS@nanoparticle composites: modifications, mechanisms, and emerging applications

Polydimethylsiloxane@nanoparticle (PDMS@NPs) composites represent a versatile class of advanced elastomers whose physicochemical behavior can be finely tuned through nanoscale interfacial design and nanofiller morphology. Owing to their inherent flexibility, transparency, and chemical stability, PDMS based systems have emerged as model platforms for developing multifunctional materials with optimized mechanical, thermal, electrical, optical, acoustic and wetting properties. This review systematically elucidates the structure property relationships in PDMS@NPs composites and the interaction mechanisms between NPs and polymer chains that enable tunable control over bulk and interfacial behavior, with particular emphasis on how NPs dimensionality and aspect ratio (0D, 1D, and 2D fillers) regulate stress transfer, transport pathways, and functional interconnectivity within the matrix. Three main NP incorporation strategies, (namely, physical mixing of presynthesized NPs, in situ synthesis on cured PDMS, and in situ formation within uncured matrices) are critically compared in terms of interfacial coupling, dispersion stability, and processing scalability. Particular attention is given to how interfacial engineering, nanofiller morphology, and hierarchical architecture govern stress transfer, phonon transport, charge percolation, and optical or surface responses. In addition, a property design prospective is presented that links interphase design and nanofiller morphology to mechanical, thermal, electrical, optical, acoustic and wetting-controlled surface properties. This review further critically examines the limiting factors that reduce the applicability of PDMS@NPs composites, including performance degradation, interface instability, and limited recyclability, as well as long-term stability under mechanical, thermal, optical, and environmental conditions. Emerging directions such as green filler synthesis, recyclable PDMS matrices , dynamic and hierarchical interphases, and predictive modeling of morphology-dependent dynamic interfaces are outlined. Overall, this review provides a comprehensive and critical perspective on PDMS@NPs composites as a next generation of soft, functional, and sustainable elastomeric materials, opening new avenues for advances in flexible electronics, soft robotics, biomedical devices, and adaptive coatings.