Basic Studies on New Stimuli-Responsive Shape Memory Ppolymers for Securing WMD
Abstract
This project focuses on developing basic understanding and control of a new series of shape memory polymers and their reinforced nanocomposites that enable unconventional all-room-temperature operations and instantaneous shape recovery triggered by applying an external pressure or exposing to an organic vapor at ambient conditions, addressing "PerD-Topic 11: Smart Materials with Unconventional Indicators for Facility Access Denial and Security of WMD Materials" described in the Broad Agency Announcement. These smart materials with unconventional indicators (i.e., pressure- and vapor-induced chromogenic properties) can provide significantly improved methods that simultaneously address detection, control/denial, and containment of Weapons of Mass Destruction (WMD) materials and facilities. Shape memory polymers are a class of "smart" materials that can memorize and recover their permanent shapes in response to an external stimulus, such as heat, light, solvent, electricity, and magnetic fields. They have been extensively exploited for a wide spectrum of technological applications, like aerospace morphing structures, sensors and actuators, self-healing materials, smart surgical stents and sutures, and implants for minimally invasive surgery. Compared with their alloy counterparts (e.g., nitinol alloy), shape memory polymers have gained increased attention due to their dramatically larger strain storage and recovery (up to 800% vs. less than 8%), low cost, light weight, ease of synthesis, and biocompatibility. However, most of the existing shape memory polymers are thermoresponsive and they suffer from slow response speed and heat-demanding programming and recovery steps. By contrast, the new stimuli-responsive shape memory polymers differ greatly from currently available ones as they enable orders of magnitude faster response and all-room-temperature operations for the entire shape memory cycle. By systematically conducting fundamental experimental and theoretical investigations, this program will address key scientific and technical issues before these smart materials can reach their full promise in DTRA-relevant counter-WMD applications. The vapor-activated chromogenic effect will be exploited as an unconventional indicator of chemical analytes (e.g., dichloromethane which is a common solvent for many chemical warfare agents like tear gas, sarin, soman and sulfur mustard) to provide warning of intrusions or presence of WMD, and/or precursors/solvents for chemical warfare agents. Additionally, the large volume expansion induced by shape memory recovery and the high surface areas of the macroporous shape memory polymer membranes will facilitate the encapsulation of WMD vapors or other materials of interest. Moreover, the basic shape memory mechanisms leading to fast response speed will be investigated to enable expandable, thin membranes to aid rapid containment of vital WMD components and render controls to section off vents, doors, or portal entrance to WMD. Furthermore, the mechanism of the unusual pressure-induced chromogenic effect will be explored as a new unconventional indicator for monitoring the movement of WMD materials and/or equipment. These fundamental experimental and theoretical investigations will lead to significant breakthroughs in a spectrum of fields ranging from self-deployable smart materials to reusable chromogenic pressure and vapor sensors to novel biometric and anti-counterfeiting materials.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 26, 2016
- Source ID
- HDTRA11510022
Entities
People
- Peng Jiang
Organizations
- Defense Threat Reduction Agency
- University of Florida