Fully autonomous, room temperature self-healing in PMMA is achieved for the first time through the use of microcapsules containing a solvent. Linear PMMA is embedded with microcapsules (ca. 300 mu m) containing a liquid anisole solvent core and a small amount of linear PMMA polymer for healing of crack damage. Specimens containing a range of concentrations of microcapsules were fracture tested and then allowed to heal for 1-7 days at ambient conditions. The healing efficiency of the material is evaluated based on the recovery of fracture toughness and is shown to be dependent on both healing time and microcapsule concentration. A maximum healing efficiency of 89% is obtained for specimens containing 5 wt% solvent microcapsules after 3 days of healing. (C) 2015 Elsevier Ltd. All rights reserved.