Bryan Boudouris
Robert and Sally Weist Associate Professor of Chemical Engineering
Telephone: (765) 496-6056
Email: boudouris@purdue.edu
More about Bryan Boudouris
Graduate Students
Darby Hoss
School: Chemical Engineering
Graduated: August, 2017
Project/Thesis: Adhesion Characterization to Improve Trace Explosives Detection Using Mesostructured Polymers
Co-Advisor: Steve Beaudoin
Jennifer Laster
School: Chemical Engineering
Graduated: December, 2017
Project/Thesis: Design of Microstructured Conducting Polymer Films for Enhanced Trace Explosives Detection
Co-Advisor: Steve Beaudoin
Aaron Woeppel
School: Chemical Engineering
Expected Graduation: May, 2023
Project/Thesis: Engineered Macromolecules for Detection of Trace Explosives Residues
Co-Advisor: Steve Beaudoin
Recent Publications
Design of free‐standing microstructured conducting polymer films for enhanced particle removal from non‐uniform surfaces
Laster, Jennifer S. ; Deom, Nicholas A. ; Beaudoin, Stephen P. ; Boudouris, Bryan W.
Journal of Polymer Science Part B: Polymer Physics, 01 October 2016, Vol.54(19), pp.1968-1974
Abstract
Efficient removal of particles from topologically‐complex surfaces is of significant import for a range of applications (e.g., explosive residue removal in security arenas). Here, we synthesize next‐generation polymeric particle removal swabs with tuned structural features to elucidate the influence of the polymer microstructure on the removal of trace particles from surfaces. Specifically, microstructured free‐standing films of the conducting polymer polypyrrole (PPy) were synthesized through template‐assisted electropolymerization techniques. The removal of polystyrene microspheres from representative aluminum surfaces of varying roughness was evaluated as a function of the PPy microstructure. PPy‐based microstructured swabs displayed increased particle trapping properties relative to non‐textured PPy‐based swabs and current commercial swabs. This increased effectiveness occurred from the more intimate particle‐swab contact, leading to increased van der Waals interactions for the microstructured swabs. Therefore, this effort provides critical design rules for the production of microstructured conducting polymer materials for their application toward advanced particle removal technologies. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. , , 1968–1974 The removal of particles from surfaces is important for a variety of applications. Here, free‐standing microstructured films of the conducting polymer polypyrrole are developed for the specific application of enhanced contact sampling for the detection of trace explosives. The influence of the polymer microstructure on the removal of model particles from a representative aluminum substrate of varying roughness is studied.
An evaluation of complementary approaches to elucidate fundamental interfacial phenomena driving adhesion of energetic materials
Hoss, Darby J ; Knepper, Robert ; Hotchkiss, Peter J ; Tappan, Alexander S ; Boudouris, Bryan W ; Beaudoin, Stephen P
Journal of Colloid And Interface Science, 01 July 2016, Vol.473, pp.28-33
Abstract
Cohesive Hamaker constants of solid materials are measured via optical and dielectric properties (i.e., Lifshitz theory), inverse gas chromatography (IGC), and contact angle measurements. To date, however, a comparison across these measurement techniques for common energetic materials has not been reported. This has been due to the inability of the community to produce samples of energetic materials that are readily compatible with contact angle measurements. Here we overcome this limitation by using physical vapor deposition to produce thin films of five common energetic materials, and the contact angle measurement approach is applied to estimate the cohesive Hamaker constants and surface energy components of the materials. The cohesive Hamaker constants range from 85 zJ to 135 zJ across the different films. When these Hamaker constants are compared to prior work using Lifshitz theory and nonpolar probe IGC, the relative magnitudes can be ordered as follows: contact angle > Lifshitz > IGC. Furthermore, the dispersive surface energy components estimated here are in good agreement with those estimated by IGC. Due to these results, researchers and technologists will now have access to a comprehensive database of adhesion constants which describe the behavior of these energetic materials over a range of settings.
Analyzing adhesion in microstructured systems through a robust computational approach
Hoss, Darby J. ; Boudouris, Bryan W. ; Beaudoin, Stephen P.
Surface and Interface Analysis, November 2017, Vol.49(11), pp.1165-1170
Abstract
Analyzing surface forces for myriad geometric structures facilitates the design of properties in interacting interfacial systems. Along these lines, we demonstrate a generalized technique that can be utilized to evaluate the orientation dependence of a particle interacting with multiple finite or semi‐infinite objects. Specifically, the surface element integration technique is modified to account for surface elements of a particle not directly adjacent to the object with which it is interacting; this facilitates the analysis of objects with finite shape and with arbitrary orientations. Furthermore, as a technology‐relevant proof‐of‐concept demonstration, the influence of van der Waals (vdW) forces on the performance and reliability of microstructured systems used for the collection of trace particles is reported. The importance of the location of the particle contact with the microstructure and the independence of vdW forces generated by each microstructure is demonstrated using the developed computational approach. Thus, the methodology presented here can ultimately be utilized for a variety of interfacial forces generated by nontrivial systems with heterogeneous properties in order to provide design motifs in a low‐cost, high‐throughput manner.
Impact of surface chemistry on the adhesion of an energetic small molecule to a conducting polymer surface
Laster, Jennifer S ; Ezeamaku, Chibuzor D ; Beaudoin, Stephen P ; Boudouris, Bryan W
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 20 August 2018, Vol.551, pp.74-80
Abstract
The modification of the surface chemistry of a film is a key strategy to enhance the binding of molecules of interest in various sensing and detection applications. For example, the adhesion of explosive residues to a swab is critical for the detection of trace explosives in air transportation environments, and it can be enhanced by increasing the affinity of the swab to target molecules through favored chemical interactions. Here, the surface chemistries of polypyrrole (PPy) films were systematically tuned through the electropolymerization of thin layers of N-substituted pyrrole monomers to evaluate their interactions with a model explosive compound, trinitrotoluene (TNT). The surface groups examined included carboxylic acid, methyl, and amino-phenyl groups, in order to address a wide range of chemical functionalities. The interaction between the functionalized PPy films with TNT was compared with the interactions between TNT and commercial swabbing materials in a vapor deposition process. The amount of TNT deposited from the vapor phase on each of the different films was quantified by the ultraviolet–visible (UV–vis) light absorbance of the Meisenheimer complex formed from the interaction of TNT with a basic solution. The PPy films with surface functionalities that allowed for hydrogen bonding displayed the highest deposition of TNT, while Teflon-coated commercial materials had the lowest interaction with TNT. Thus, this work provides insight into the surface groups of interest for the enhanced collection of trace explosives as well as the critical design criteria for the next generation of swabbing materials.
Energetic Microparticle Adhesion to Functionalized Surfaces
Hoss, Darby J. ; Mukherjee, Sanjoy ; Boudouris, Bryan W. ; Beaudoin, Stephen P.
Propellants, Explosives, Pyrotechnics, September 2018, Vol.43(9), pp.862-868
Abstract
Surface chemistry influences interfacial interactions, and while these interactions have been evaluated in many synthetic and biological systems, they have important but unexplored implications in trace explosives detection. Specifically, the detection of energetic materials is a challenging, urgent goal, and one of the most common means by which this effort is implemented at air transportation checkpoints is using methods based on contact sampling. Elucidating the molecular and interfacial interactions of energetic materials with functionalized surfaces provides fundamental knowledge and also advances the goal of improved materials for trace detection. Here, in order to evaluate the effects of specific functional groups on adhesion, atomic force microscopy (AFM) pull‐off force measurements were performed using nitrate‐based energetic (and non‐energetic) particles against self‐assembled monolayers (SAMs) of representative chemical functionalities. These SAMs‐on‐gold substrates were selected to evaluate surface chemistry effects due to their reproducibility, facile production, and versatile tunability. In addition to the experimental results, stabilization energies for the optimized most‐stable configurations for a coupled receptor‐analyte system were determined using density functional theory (DFT). From these combined experimental and computational efforts, it is established that the adhesion between detection surfaces and common energetic materials at the macroscopic scales is correlated to the interaction energies at the molecular level. Moreover, the electron deficient nature of nitro‐rich energetic compounds results in stronger interactions with surfaces functionalized with electron‐donating units. Ultimately, these results will facilitate the rational design of energetic particle collection materials through chemical tailoring in order to enhance the detection and defeat of explosive materials.