(698f) First-Principles Design of Nerve Agent Sensing Systems Using Chemoresponsive Liquid Crystals

Authors: 
Gold, J., University of Wisconsin-Madison
Szilvási, T., University of Wisconsin-Madison
Abbott, N. L., Cornell University
Mavrikakis, M., University of Wisconsin-Madison
Nerve agents (NAs) are some of the most lethal compounds that have been synthesized by mankind. Developing portable sensors to explore critical environments with unmanned vehicles can help deter potential future incidents. One such option for portable, cheap, and lightweight sensors is to use chemoresponsive liquid-crystalline based materials. These chemoresponsive materials exhibit an optical response via surface-induced orientation transitions caused by the competitive binding of the liquid crystal molecule and a targeted chemical analyte, such as organophosphate nerve agents,1 to a tailored solid surface.2,3 We have recently developed quantum chemical models to capture experimental parameters that influence the orientational response of these liquid-crystalline materials to organophosphorus compounds. We benchmarked these models against experimental results using non-toxic NA simulants because the danger actual NAs pose to humans and society make it a challenge to perform experiments with these chemicals.1,4–6 Using computational models, we have provided important guidance for accelerated design of chemoreponsive liquid crystals for NAs, thus minimizing experimental workload involving these dangerous compounds.

In this presentation, we will address how chemical properties of NAs dictate orientational transition of liquid crystals on surfaces that present metal cation binding sites. We show that there are large differences in binding properties among the NAs; thus emphasizing the need to use distinct NA simulants for different NAs. We show that there are clear trends in binding properties of NAs and their simulants that are independent of the surfaces studied. Building on these general trends, we propose optimal NA simulants for NAs and optimal liquid-crystalline systems to detect different NAs.

1. Cadwell, K. D.; Lockwood, N. A.; Nellis, B. A.; Alf, M. E.; Willis, C. R.; Abbott, N. L., Sensors Actuators B, 2007, 128, 91.

2. Shah, R. R.; Abbott, N. L., Science, 2001, 293, 1296.

3. Cadwell, K. D.; Alf, M. E.; Abbott, N. L., The Journal of Physical Chemistry B, 2006, 110, 26081.

4. Roling, L. T.; Scaranto, J.; Herron, J. A.; Yu, H.; Choi, S.; Abbott, N. L.; Mavrikakis, M., Nature Communication, 2016, 7, 13338.

5. Yu, H.; Szilvási, T.; Rai, P.; Twieg, R. J.; Mavrikakis, M.; Abbott, N. L., Advanced Functional Materials, 2018, 28, 1703581.

6. Szilvási, T.; Bao, N.; Yu, H.; Twieg, R. J.; Mavrikakis, M.; Abbott, N. L., Soft Matter, 2018, 14, 797.