The goal of this basic research is to obtain a fundamental understanding of the surface enhancement that can be achieved in Raman spectroscopic analysis of organic compounds using a variety of functionalized nanomaterials in suspension. Surface enhanced Raman spectroscopy (SERS) is a well-established technique for improving Raman sensitivity, however, not all bond vibrations are equally enhanced and molecules have to tightly couple to the surface to experience enhancement. To achieve our objective, we will examine and compare enhancement from a new class of gold nanomaterials with traditional gold nanospheres and gold nanostars. Additionally, all three nanomaterials will be functionalized with a variety of self-assembled monolayers (SAMs) containing different terminal functional groups as molecular capture reagents. Our long-term goal is to examine molecules of interest to the warfighter, however, this proposal will start by utilizing a diverse molecular fragment library to understand the physiochemical properties of molecular capture and the specific functional groups that exhibit vibration enhancement as a function of nanomaterial and capture ligand.

Carbon nanomaterials are a promising nanoscale platform to construct next generation systems for high performance, light-weight, and configurable energy storage and conversion devices and sensors. Recent advances in nanotechnology and materials science have led to the development of novel materials with different size, geometry and surface area. However, the design, synthesis, and assembly of these nanomaterials with well-defined structure and connection from nanoscale entities to real world device applications continues to present big challenges. Therefore, my primary academic research interest is the incorporation of these nanomaterials into energy storage and conversion systems by controlling the precise connection of the individual components at the molecular level with other materials in order to build miniaturized nanostructures coupled to develop wearable electronics and batteries, structural power devices, optoelectronics, and chemical and biological sensors.

Currently, the Army fields both portable Fourier transform (FT) Raman and infrared spectrometers for unknown analysis.  These devices are portable, light-weight, and capable of identifying a broad array of contaminants using built-in spectral libraries.  However, the detection sensitivity of these devices is extremely limited. There is a critical need to enhance the sensitivity and accuracy of these forward deployed devices for the detection of a range of chemical (and possibly biological) agents.  If the sensitivity of these devices could be enhanced, one would be able to provide increased warfighter protection without incurring the cost of investing in new technology and training, and without increasing the physical burden on the soldiers.

Approach: Employ transition metal salt-templating of nanoparticles with subsequent noble metal galvanic displacement to dendritic nanostructures for enhanced SERS:

Year 1: Understanding the Impact of Shape and Surface Functionalization on SERS Enhancement for Prototypical Non-Polar, Polar, and Charged Molecules.

Year 2: Understanding Specific Bond Vibration Enhancement Using Fragment Library Screening and Machine Learning (ML) Algorithms.

Year 3: Discriminating Real Molecules in Complex Mixtures.

Objective: Develop the capability for rapid sensing and screening of toxic chemical and biological contaminants.

Reaction centers (RCs) harvest green and infrared photons and result in stable charge separation.  Resulting electrons are picked up by quinone (a diffusible electrolyte) and cytochrome c is responsible for refilling the electron hole. Preliminary work performed at USMA in the Multi-Functional Materials Laboratory shows promising performance of purified RCs on graphene.  We plan to continue these studies to test the hypotheses of whether reaction centers can be successfully coupled electronically or fluorescently to graphene oxide or carbon nanotubes, and to examine the possibility of coherence playing a role in the process of energy conversion to further increase efficiency. Engineered reaction centers modified to sense the environment and result in a measurable current can also be utilized in detecting threats and other valuable targets. Our research will propel the advancement of biomaterial-based light harvesting that will result in higher current outputs than previously published proof-of-concept work. This project builds on previously published efforts demonstrating successful interfacing of impure biomaterials resulting in a light-dependent current.

Per-and Poly-fluoroalkyl Substances (PFAS) Detection

The United States Military Academy (West Point) in collaboration with U.S. Army Futures Command, Combat Capabilities Command Armament Center (CCDC-AC) and the University of Rhode Island (URI) are working to develop preliminary data for emissions from thermal destruction of PFAS components in munitions identified for demilitarization or disposal. A investigative data driven study to determine the actual risk of emitting PFAS substances into the atmosphere during thermal degradation and the inherent risk to human health and the environment is ongoing. This study is funded through a $115,000 grant from CCDC-AC.

Soft Robotics

The human-robot interface is critical to future operations. Development of inexpensive, highly modified, tailored soft robotic systems is of vital importance to develop autonomous and semi-autonomous robotic platforms that are able to complete complex and delicate procedures. Pneumatic soft robotics affords human like movement and capabilities of various human musculoskeletal systems. Scientific research and technology directed toward optimizing Soldier performance and Soldier-machine interactions to maximize battlefield effectiveness, and to ensure that Soldier performance requirements are adequately considered in technology development and system design. These design efforts are funded through a $5,935 grant from U.S. Army Futures Command, Combat Capabilities Development Command Army Research Laboratories (CCDC-ARL).