The growing use of mobile devices that are available everywhere can blur the boundaries between life domains work and life. The increasing number of notifications on smartphones leads to interruptions that might be unrelated to the current life domain and task and are therefore disruptive. Despite some tools there is a gap between the preferred and the actual separation of life domains. In this paper we show how concepts from the field of boundary management can be applied for notification management on mobile devices. We present a formal model of the semantic structure of life domains, which is based on the concepts of integration and segmentation from boundary theory. We introduce an app for the management of notifications on Android smartphones that leverages on this formal model. In a field study we evaluated the app with real-life notifications. The results show a significant reduction of the gap between actual and preferred boundary management.