A super‐stretched self‐healing silicone elastomer based on high molecular weight polydimethylsiloxanes through intermolecular quadruple hydrogen bonding

Abstract

Supramolecular silicone elastomer is a promising material for sustainable development. Here, quadruple hydrogen bonded ureidopyrimidinone (UPy) units were grafted onto high molecular weight polydimethylsiloxanes (PDMS), providing a novel supramolecular silicone elastomer. The high molecular weight PDMS precursor was prepared through a cyclic trimeric phosphazene base catalyzed ring‐opening polymerization of Octamethylcyclotetrasiloxane (D4) and tetravinyltetramethylcyclotetrasiloxane (V4) with a well‐controlled vinyl content. Its side chains were modified by hydroxyl groups via a thiol‐ene reaction. Then UPy units were further grafted on the side chain of high molecular weight PDMS by the isocyanate‐hydroxy reaction. The mechanical and self‐healing properties of the elastomer can be controlled by adjusting the molecular weight of PDMS and the amount of UPy units. The obtained PDMS elastomers displayed excellent stretchability (elongation at break of 1513%), good self‐healing efficiency (76% at 60°C for 2 h), and high resilience (elastic recovery of 93% under 300% strain cyclic stretching).

Self-Healing Silicone Materials: Looking Back and Moving Forward

“…Along with SHSMs based on covalent reversible cross-links, there are elastomers with dynamic non-covalent interactions: hydrogen [ 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 , 96 , 97 , 98 , 99 , 100 , 101 , 102 , 103 , 104 , 105 , 106 , 107 ] and ionic bonding [ 108 , 109 , 110 , 111 ], π–π-stacking [ 87 , 112 , 113 ], metal–metal [ 87 ], and host–guest interactions [ 114 ] ( Figure 9 ). Some examples of non-covalent SHSMs are shown in Table 1 .…”

“…Hydrogen bonding is the most common reversible interaction used to form SHSMs [ 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 , 96 , 97 , 98 , 99 , 100 , 101 , 102 , 103 , 104 , 105 , 106 , 107 ] ( Figure 10 ). The hydrogen bonds are chemical bonds between an electronegative atom (N, O, or F) and a hydrogen atom covalently bonded to another electronegative atom.…”

“…In the last five years (2018–2023), various hydrogen-bonded SHSMs and composites based on them have been obtained [ 93 , 94 , 95 , 96 , 97 , 98 , 99 , 100 , 101 , 102 , 103 , 104 , 105 , 106 , 107 ]. These SHSMs are based on PDMS copolymers and urethanes, nitrogen-containing heterocyclic, and amine-containing moeties ( Figure 10 c–n).…”

“… Some examples of hydrogen-bond-type SHSMs [ 89 ] ( a ), [ 91 ] ( b ), [ 90 ] ( c ), [ 98 ] ( d ), [ 92 ] ( e ), [ 93 ] ( f ), [ 94 ] ( g ), [ 99 ] ( h ), [ 100 ] ( i ), [ 101 , 102 ] ( j ), [ 103 ] ( k ), [ 107 ] ( l ), [ 104 ] ( m ), and [ 105 ] ( n ). …”