Fabrication of advanced polydimethylsiloxane-based functional materials: Bulk modifications and surface functionalizations

With the rapid progress of artificial intelligence, robot and medical services, soft polymers with changeable modulus and flexible machinability have become an important kind of strategic materials. Among them, a polydimethylsiloxane (PDMS)-based material is regarded as a promising one due to its flexible chemistry and biocompatibility. Two modification methods are always involved in practical applications of PDMS-based materials, i.e., bulk modifications and surface functionalizations. The former mainly aims to improve the poor mechanical strength of PDMS, while the latter is conducted to meet some functional requirements in the field of smart structures, e.g., surface wettability, anti-freezing, self-cleaning and strong adhesion. As a result, design and fabrication procedures in the modification of PDMS-based materials arise as important and attractive hotspots. In this review, we summarize the recent advances in not only bulk modification strategies for PDMS-based materials but also in the functionalizing methods to realize various surface functions. Correlations between material properties and structural factors including chemical constitution and micro/nano structures are further extracted for guiding the modification of PDMS-based materials. The challenges and prospects in developing surface-functionalized PDMS-based materials are also presented and concluded. It is hoped that this review could help to better understand modification technologies of PDMS-based materials and even stimulate some new thoughts for design and preparation of smart soft materials.