Dynamic siloxane materials: From molecular engineering to emerging applications

Dumbbell‐Shaped, Graft and Bottlebrush Polymers with All‐Siloxane Nature: Synthetic Methodology, Thermal, and Rheological Behavior

“…Silicon-containing derivatives, including (poly)silanes [33,34] and especially poly(organosiloxanes) (siloxanes), are of high interest and offer special prospects among well-defined organometallic and inorganic macrostructures (and materials based on them). [35][36][37][38][39] This is due, on the one hand, to the abundance and availability of "Si" in the Earth's crust (27.6-29.5 mass%), and on the other hand, to the unique set of physicochemical properties of siloxane materials, PDMS and PDES in particular, such as high thermal resistance, low glass transition temperature, radiation resistance, gas permeability, biocompatibility, etc. [35][36][37][38][39] However, the synthesis of complex macromolecules with an all-siloxane nature (i.e., with SiOSi groups both in the main chain (or core) and in the side chain (pendant), in particular with grafted, [40] dumbbell-shaped, [41] star-shaped structure, [41][42][43] etc., is still a non-trivial challenge.…”

“…[35][36][37][38][39] This is due, on the one hand, to the abundance and availability of "Si" in the Earth's crust (27.6-29.5 mass%), and on the other hand, to the unique set of physicochemical properties of siloxane materials, PDMS and PDES in particular, such as high thermal resistance, low glass transition temperature, radiation resistance, gas permeability, biocompatibility, etc. [35][36][37][38][39] However, the synthesis of complex macromolecules with an all-siloxane nature (i.e., with SiOSi groups both in the main chain (or core) and in the side chain (pendant), in particular with grafted, [40] dumbbell-shaped, [41] star-shaped structure, [41][42][43] etc., is still a non-trivial challenge. [44,45] As a rule, combined (mixed) systems are obtained, that is, those consisting of a siloxane (SiOSi moieties) main chain (or core) and carbosilane (Si(C) n Si moieties, n = 2,3) side chains, and vice versa, or systems with both siloxane main chain (or core) and side A methodology for synthesizing a wide range of dumbbell-shaped, graft and bottlebrush polymers with all-siloxane nature (without carbosilane linkers) is suggested.…”

Reprocessable Supramolecular Elastomers of Poly(Siloxane–Urethane) via Self‐Complementary Quadruple Hydrogen Bonding

“…These unprecedented properties are attributed to the dynamic nature of supramolecular bonds, whose energies are low enough to allow bond exchanging under mild conditions. Various types of noncovalent interactions, such as hydrogen bonding, [11,12] ionic bonding, [13][14][15][16][17] and metal-ligand coordination, [18][19][20][21][22] have been exploited to build supramolecular silicone materials. Typical examples are thermoplastic elastomers of poly(siloxane-urethane) [23,24] and poly(siloxane-urea), [25,26] where the hydrogen bonding of urethane/urea units and the phase separation between soft polysiloxane segments and hard polyurethane/polyurea are responsible for their excellent mechanical properties and thermoplastic abilities.…”

“…[ 1–4 ] In particular, polydimethylsiloxane (PDMS) is praised for its excellent biocompatibility, high gas permeability, low glass transition temperature ( T g ), low surface energy, good thermal and oxidative stability, and water repellency. [ 5–8 ] Over the past decade, supramolecular silicone materials [ 9,10 ] have attracted much attention due to their outstanding properties, such as high stiffness, high stretchability, self‐healing ability, and thermoplastic capacity. These unprecedented properties are attributed to the dynamic nature of supramolecular bonds, whose energies are low enough to allow bond exchanging under mild conditions.…”

Construction of Self-Healing Disulfide-Linked Silicone Elastomers by Thiol Oxidation Coupling Reaction

“…Silicone elastomers (SEs) as an important class of organosilicon materials have attracted significant interest due to their intriguing properties, such as high/low temperature resistance, high surface activity, electric resistance, and biocompatibility, and have found extensive applications in aerospace, electronics, coatings, adhesives, medicine, and so forth [1][2][3][4]. Recently, SEs with a self-healing property have gained particular attention because this property not only can lead to the extension of their usable life, recycling, and reduction of waste, but also can meet their high requirements in emerging applications, such as stretchable electronics, wearable strain sensors, and soft robots [5][6][7]. The SEs with a self-healing property are typically realized by pre-embedded a healing agent in the system (called extrinsic self-healing), or incorporating dynamic linkers in the networks (called intrinsic self-healing) [6].…”