Improved Swab Design for Contact Sensing [INACTIVE]

Download Project Report (Phase 2, Year 5).

Project Description


Contact sampling is at the heart of current methods of explosives interdiction at air transportation venues. This involves the use of “swabs” or “wipes” which are passed over surfaces of interest, such as purses and laptops, to collect any possible residues of explosives that were deposited by a potential terrorist.

The swabs are then passed through an ion mobility spectrometer (IMS).  In the IMS, the wipes are rapidly heated to roughly 250°C to desorb any residue, which is subsequently detected in the spectrometer. Swabs can then be reused to detect residue on the next item. Current swabs are optimized to survive the high temperatures of the desorber, but not to interrogate surfaces.

This project develops meso-engineered polymeric swabs with customized surface topography, electrical properties, mechanical properties, and surface chemistry, to provide superior residue harvesting capabilities. Prototype first generation swabs have been assembled and are undergoing testing. Second generation swabs are being developed with a focus on optimizing the composition of the swabs by attaching various functional groups to their surfaces.  By systematically varying the composition of the swabs’ surfaces, it is possible to tune that adhesion of the residues to the swabs during residue harvesting and during residue release in the IMS.  The envisioned product from this research will be a superior swab that can survive multiple trips through an IMS and that will offer improved residue harvesting and release compared to existing swabs.


When this project succeeds, the swabs that we deliver will improve the effectiveness of checkpoint security activities based on contact sampling/IMS at a low cost.
Year 4 Annual Report
Project Leader
  • Stephen P. Beaudoin
    Purdue University

Faculty and Staff Currently Involved in Project
  • Byran Boudouris
    Assistant Professor
    Purdue University

Students Currently Involved in Project
  • Darby Hoss
    Purdue University