A Self‐Healing Poly(Dimethyl Siloxane) Elastomer

Abstract

Self‐healing functionality is imparted to a poly(dimethyl siloxane) (PDMS) elastomer. This new material is produced by the incorporation of a microencapsulated PDMS resin and a microencapsulated crosslinker into the PDMS matrix. A protocol based on the recovery of tear strength is introduced to assess the healing efficiency for these compliant polymers. While most PDMS elastomers possess some ability to re‐mend through surface cohesion, the mechanism is generally insufficient to produce significant recovery of initial material strength under ambient conditions. Self‐healing PDMS specimens, however, routinely recover between 70–100 % of the original tear strength. Moreover, the addition of microcapsules increases the tear strength of the PDMS. The effect of microcapsule concentration on healing efficiency is also investigated.

Self-healing epoxy via epoxy–amine chemistry in dual hollow glass bubbles

“…Variety approaches have been proposed to improve the fragile feature of the epoxy resin, among which the incorporation of self-healing functionality [2][3][4] is very promising because of the toughening effect by the added healing agent carriers as micro-fillers [5] and the re-bonding of the induced micro-cracks timely upon their formation. Self healing in epoxy can be realized by various means in different scales, such as by layup of hollow tubes [6][7][8][9][10][11][12], fabrication of micro-vascular networks [13], microencapsulation [14][15][16][17][18][19][20][21], thermal additives [22], as well as molecular design by Diles-Alder reaction [23]. Attributed to the ease of manufacture and material integration, the embedment of microcapsules containing healants is the most popular approach among all the methods.…”

The use of nano-/microlayers, self-healing and slow-release coatings to prevent corrosion and biofouling

“…Liquid paints with capsules are also an active area of research, with most of the coatings applied with brush or drawer. Spray-applying is not yet in practice (Keller et al, 2007). Capsules reduce adhesion when embedded directly onto a layer near to the metal surface (Keller et al, 2007), with the exception that sol-gel particles bond covalently onto oxide layers.…”

“…Spray-applying is not yet in practice (Keller et al, 2007). Capsules reduce adhesion when embedded directly onto a layer near to the metal surface (Keller et al, 2007), with the exception that sol-gel particles bond covalently onto oxide layers. In certain cases inhibitors change the coating structure thus their encapsulation improves barrier properties (Dias et al, 2012). 7.9 References Ai, J.Z., Guo, X.P.…”

“…Tributyltin-derivatives have been banned since 2008 because of their toxicity (Dafforn et al, 2011). The most common core substances for self-healing systems are dicyclopentadiene and Grubbs catalysts (White et al, 2001), epoxy resins (Zhao et al, 2012;Liu et al, 2012), diglycidyl ether bisphenol-A based epoxy resins with an imidazole hardener (Rong et al, 2007), mercaptan compounds and cationic initiators BF 3 .OEt 2 , vinyl functionalized poly(dimethylsiloxane) resins and platinum catalysts (Keller et al, 2007), styrene (Wang et al, 2008, Wang et al, 2009, polythiol epoxy hardeners , reactive amines (McIlroy et al, 2010), diisocyanate resins , methyl(methacrylate) . ils draying on air can be used in coatings contacted with air: linseed oil (Selvakumar et al, 2012, Szabó et al, 2011, Boura et al, 2012, Nesterova et al, 2012), tung oil ( Samadzadeh et al, 2011), water-reactive silyl ester (García et al, 2011).…”

Self-healing polymers and composites

“…In most reports of microcapsule based self-healing mechanisms, increasing loadings of liquid filled capsules significantly toughens the composite matrix, relative to 29,226 Epoxy resin filled capsules/solid imidazole catalyst 37 Epoxy resin/mercaptan filled capsules 43 Phase separated pEMAA particles 117 DCPD filled capsules/solid, wax encased Tungsten catalyst 85 Shape memory alloy wires 79,80 Epoxy resin filled capsules/matrix dissolved imidazole catalyst 38,40,41 Matrix dissolved thermoplastic polymer 155 Strength Epoxy resin-filled capsules/matrix dissolved imidazole catalyst (CAI) 42 PDMS containing capsules (tear) 46 Epoxy resin filled hollow fibres: large pitch spacing (flexural) [133][134][135] Epoxy resin filled microvascular network (flexural) 153 Epoxy resin filled hollow fibres: small pitch spacing (flexural) [132][133][134] Epoxy resin/mercaptan filled capsules (flexural, tensile) Phase separated Epoxy polymer particles (tension) 115,116 Phase separated pEMAA particles (flexural) 117 Phase separated poly(caprolactone) (storage) 119 …”