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The structural design of self-healing materials determines the ultimate performance of the product that can be used in a wide range of applications. Incorporating intrinsic self-healing moieties into puncture-resistant materials could significantly improve the failure resistance and product longevity, since their rapidly rebuilt bonds will provide additional recovery force to resist the external force. Herein, we present a series of tailored urea-modified poly(dimethylsiloxane)-based self-healing polymers (U-PDMS-SPs) that exhibit excellent puncture-resistant properties, fast autonomous self-healing, multi-cycle adhesion capabilities, and well-tunable mechanical properties. Controlling the composition of chemical and physical cross-links enables the U-PDMS-SPs to have an extensibility of 528% and a toughness of 0.6 MJ m −3 . U-PDMS-SPs exhibit fast autonomous self-healability with 25% strain recovery within 2 minutes of healing, and over 90% toughness recovery after 16 hours. We further demonstrate its puncture-resistant properties under the ASTM D5748 standard with an unbreakable feature. Furthermore, the multi-cycle adhesive properties of U-PDMS-SPs are also revealed. High puncture resistance (>327 mJ) and facile adhesion with rapid autonomous self-healability will have a broad impact on the design of adhesives, roofing materials, and many other functional materials with enhanced longevity. 

Recent findings that the association bond lifetimes τ α* in associating polymers diverge from their supramolecular network relaxation times τ c challenge past theories. The bond lifetime renormalization proposed by Rubinstein and coworkers [Stukalin et al. , Macromolecules , 2013, 46 , 7525] provides a promising explanation. To examine systematically its applicability, we employ shear rheology and dielectric spectroscopy to study telechelic associating polymers with different main chain (polypropylene glycol and polydimethylsiloxane), molecular weight (below entanglement molecular weight) and end groups (amide, and carboxylic acid) which form dimeric associations by hydrogen bonding. The separation between τ c (probed by rheology) and τ α* (probed by dielectric spectroscopy) strongly increases with chain length as qualitatively predicted by the model. However, to describe the increase quantitatively, a transition from Rouse to reptation dynamics must be assumed. This suggests that dynamics of super-chains must be considered to properly describe the transient network. 

Utilization of self‐healing chemistry to develop synthetic polymer materials that can heal themselves with restored mechanical performance and functionality is of great interest. Self‐healable polymer elastomers with tunable mechanical properties are especially attractive for a variety of applications. Herein, a series of urea functionalized poly(dimethyl siloxane)‐based elastomers (U‐PDMS‐Es) are reported with extremely high stretchability, self‐healing mechanical properties, and recoverable gas‐separation performance. Tailoring the molecular weights of poly(dimethyl siloxane) or weight ratio of elastic cross‐linker offers tunable mechanical properties of the obtained U‐PDMS‐Es, such as ultimate elongation (from 984% to 5600%), Young's modulus, ultimate tensile strength, toughness, and elastic recovery. The U‐PDMS‐Es can serve as excellent acoustic and vibration damping materials over a broad range of temperature (over 100 °C). The strain‐dependent elastic recovery behavior of U‐PDMS‐Es is also studied. After mechanical damage, the U‐PDMS‐Es can be healed in 120 min at ambient temperature or in 20 min at 40 °C with completely restored mechanical performance. The U‐PDMS‐Es are also demonstrated to exhibit recoverable gas‐separation functionality with retained permeability/selectivity after being damaged.