title: Robust, double-walled microcapsules for self-healing polymeric materials.
abstract: Double-walled polyurethane/poly(urea-formaldehyde) microcapsules (PU/UF) are prepared for use in self-healing materials. This modified encapsulation procedure combines two chemistries to form more robust capsule shell walls in a single operation. Robust capsules are formed by this procedure as long as the aromatic polyisocyanate prepolymer is soluble in the core liquid and the core liquid is compatible with isocyanates. Compared to a standard UF encapsulation, the modified procedure results in capsules with an increase in shell wall thickness from 200 to 675 nm as a function of the amount of PU added to the core liquid. Thermal stability of PU/UF microcapsules prepared with varying amounts of PU is compared to UF microcapsules. Mechanical properties of the PU/UF microcapsules are assessed from single-capsule compression testing.
authors.affiliation: Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors.forename: Mary M
authors.initials: MM
authors.lastname: Caruso
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Blaiszik
authors.forename: Henghua
authors.initials: H
authors.lastname: Jin
authors.forename: Stuart R
authors.initials: SR
authors.lastname: Schelkopf
authors.forename: Dylan S
authors.initials: DS
authors.lastname: Stradley
authors.forename: Nancy R
authors.initials: NR
authors.lastname: Sottos
authors.forename: Scott R
authors.initials: SR
authors.lastname: White
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Moore
mesh_terms: D002214:Capsules / Q000737:chemistry*; D004867:Equipment Design; D005557:Formaldehyde / Q000737:chemistry; D006358:Hot Temperature; D017953:Isocyanates / Q000737:chemistry; D008422:Materials Testing; D018625:Microscopy, Atomic Force / Q000379:methods; D011108:Polymers / Q000737:chemistry*; D013314:Stress, Mechanical; D013696:Temperature
chemical_list: D002214:Capsules; D017953:Isocyanates; D011108:Polymers; D005557:Formaldehyde; C045786:polyurea