Chemo-mechanical polymer constructs for feedback, homeostasis, and oscillation: 7.3 Polymer Chemistry
Abstract
This effort seeks to develop a fundamentally new approach to endow materials with chemo-mechanical coupling that allows for tunable oscillatory or homeostatic behaviors that will be generalizable to a wide range of chemical reactions, materials systems, and environmental conditions. If successful, this work will enable revolutionary advances in the design of responsive material systems with embedded feedback which will afford new opportunities in the development of autonomously operating and adaptive materials. To achieve the aforementioned objective, the P1 will: 1. Fabricate structurally robust and active catalyst films that can be integrated with shape-changing responsive polymer constructs: The P1 will extend the previously developed platform of photo-crosslinkable polymers containing pendent benzophenone groups to pattern urn- to mm-scale constructs that combine responsive polymer elements with catalytically active polymer nanocomposites. As a model chemical reaction, research will focus on the oxidation of glucose to gluconic acid using gold nanoparticle catalysts. Measurements of film thickness, refractive index, UV-vis absorbance, and morphology will be used to determine the level of catalyst loading and aggregation or surface segregation. 2. Elucidate the kinetics of reaction, diffusion, and swelling within these micro-patterned polymer materials: In parallel with aforementioned efforts to develop well-dispersed and structurally robust polymer/catalyst nanoconiposite films, the PI plans to study the kinetic parameters of reaction and diffusion within these materials as well as to characterize the swelling kinetics of the responsive hydrogel films that will be used to drive changes in shape. 3. Establish the regimes under which such responsive polymer/catalyst constructs exhibit homeostatic and large-amplitude oscillatory behavior: As a first generation mechanism for enabling chemo-mechanical feedback through changes in shape, the P1 will fabricate self-folding chemo-mechanical constructs exhibiting homeostatic and oscillatory behaviors. Images of the time-dependent bending will be recorded using an inverted optical microscope, while a pH-indicating fluorophore will be used to measure the time-dependent pH profile around the construct by confocal microscopy. In addition to developing a detailed understanding of where in parameter space horneostatic and oscillatory behaviors are seen, the P1 also intends to characterize the stability of these behaviors in response to environmental changes (i.e., in pH, temperature, or reactant concentrations in the reaction medium), and study how the constructs respond to mechanical perturbation 4. Understand communication and signal propagation in coupled arrays of oscillating constructs: As the final goal of the project, the PI will study the behavior of arrays of coupled chemomechanical constructs as a first step toward developing complex networks of communicating elements. Focusing on conditions identified as leading to robust large amplitude oscillations (Step 3), the team will fabricate simple linear arrays of oscillators and will study how chemo-mechanical coupling depends on the size and spacing of the oscillators, as well as whether the catalyst is placed on the moving or stationary panel. Additionally, the PI plans to study simple two-dimensional arrays of oscillators.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 12, 2017
- Source ID
- W911NF1610119
Entities
People
- Ryan C Hayward
Organizations
- Army Contracting Command
- United States Army
- University of Massachusetts Amherst