Projects

Concept Paper

The assignment is to use some of your knowledge and understanding of polymer design and synthesis to create a concept paper that describes an approach to generating a polymer for a specific application. In general, this concept paper should allow a great deal of flexibility in how you shape and define your chosen topic. It is expected that you will do some preliminary investigation of what has been done and is already in the literature. You are encouraged to either improve or modify a specific type of system, or create a new one based on your understanding of the problem. Please avoid just reporting on an already existent system; introduce some new chemistries or capabilities into your materials system. Those of you who want to do something related to your thesis project, please let me know and we can discuss how to best accomplish this - the danger here is I will not know how much of the design idea to credit to you versus your thesis supervisor or lab collaborators.

You should be sure to address the challenges presented in your chosen problem and how your materials design will get around some of those problems. Once you have selected or designed a given polymer system, determine:

• Whether the polymer(s) needed is main chain or side chain functional polymer.
• Whether it is stable to the conditions to which it might be exposed.
• The sorts of polymerization techniques available to synthesize the polymer. If relevant, discuss whether there are any processing issues, cost issues, etc.
• The relevance (if any) of molecular weight, molecular weight distribution, or both, in your polymer.
• Whether the system you have chosen is a thermoset/gel or thermoplastic, and what means would be used to process it.

All papers should focus on the different synthetic approaches possible to make the polymer, and address issues involved and options available. Explain why the route you chose was picked and why it is required or preferred.

Your paper should be roughly 5 to 10 pages, single-spaced, not counting references. Be brief in your literature review, but be certain to include all your references.

Concept Paper Topics

1. New High Performance Degradable Polymers for Environmental Applications

   This area is a continued challenge, as it requires some mechanical integrity in a polymer which is designed to ultimately undergo degradation at the right conditions. Biggest applications are in packaging films and cheap throw-away products. In the packaging area, a big challenge is to maintain the barrier properties in a system (e. g. keeping gases in or out of a soda bottle) while making it degradable.

2. Polymers for Chemical or Biological Sensing

   Design or modify a polymer which can be used as part of the active component in a sensing system for chemicals (ranging from hazardous materials, environmental materials, heavy ions, or chemical warfare agents) or detecting biological hazards. You may want to consider polymers or copolymers that combine one or more functions, e. g. detection and remediation, or which have extremely high sensitivities. Is your system functional within the main chain or through attached side groups? Address processing issues, solubility, stability, etc.

3. Polymers for Tissue Engineering

   Design a polymer system for directed cell attachment and growth in 2D or 3D scaffolds. Does your polymer allow for the biocompatibility needed? Does it have the mechanical properties, porosity, permeation, or other properties needed? How can you treat the surface of the polymer or introduce an additional polymer that promotes adhesion of the cells? Does the design of your polymer require side or main chain functionality? Would you choose a biodegradable backbone or side group? Address different approaches, and you reason for choosing your system.

4. Selective/Responsive Gas or Liquid Phase Membranes

   Design a polymer for use as a selective membrane. You may choose the specific membrane problem of interest. Either gas or liquid phase separations applications may be considered. Of particular interest would be a) materials with well-controlled pore sizes or b) "switchable" or tunable membranes which change their perm-selectivity based on either environmental changes or the influence of an electromagnetic field (light, electric, magnetic). Determine the best approach for synthesizing your material. Discuss how it might be processed into its final form. Organic-inorganic hybrids with catalytic metals may also be considered.

5. Fuel Cell Proton Exchange Membrane

   One of the issues that limit our use of fuel cells as a means of energy in multiple applications is the high commercial costs and the limitations of polymers used for the proton exchange membrane in both hydrogen and methanol fuel cell systems. The proton exchange membrane must promote the conduction of protons and prevent diffusion of the fuel gases such as hydrogen and oxygen into the membrane. The most commonly used polymer is Nafion® from DuPont, a poly(perfluorosulfonyl ether) that contains sulfonic acid groups that essentially line pores of the film to allow proton transport. Limitations include the limited range of humidity for operation and fuel cross-over, particularly in liquid methanol fuel cells.

6. Low Dielectric Material

   Design a polymeric system for use as a low dielectric constant material that might be used as an insulating layer in the manufacture of chips in the semiconductor industry. In many cases, materials with microcellular morphologies or composite materials have been considered. Address how your system achieves a low dielectric constant, and whether it is competitive with existing technologies. What pitfalls or challenges exist? How would your system be processed?

7. Artificial Muscle (Actuator) or Shape Memory Polymers

   Many researchers are interested in creating polymeric elastomeric materials that can undergo moderate deformations on activation with electrical field, magnetic field, pH or salt content. The materials systems used range from swollen polymer networks such as hydrogels to polymer composites containing magnetic particles. Investigate various potential polymer based systems, and then design/select a polymer system for this application.

8. Tough, Energy Absorbing Polymer Materials

   The goal here would be to obtain flexible, elastomeric polymers with the high strength seen in natural polymers. One might consider "synthetic" polypeptides or related materials, or even cellular synthesis of made-to-order polymers (see, for example, the work of David Tirrell). One could also consider synthetic analogs of these materials. Organic-inorganic hybrid materials might be designed to mimic naturally tough materials such as shell (nacre); however, you must consider how to design a polymer that is compatible with or that has a strong interfacial interaction with the inorganic system.

Design Questions to Ask About Your Projects

• What type of backbone is desired?
  • Rigid, Flexible, Stable (to air, heat, water, environment…)
• What morphology might be obtained or desired, and how would you synthesis scheme affect morphology?
  • Semi-crystalline, Amorphous, Phase segregated
• Are chosen chemical functional groups on monomer susceptible to attach in the polymerization approach?
• What kind (if any) side group would be used?
• What percentage substitution is needed (if relevant)?
• Is stereochemistry or are stereoisomers important?
• Is polydispersity important?
• Is high vs. low molecular weight critical or relevant?
  • Mechanical properties, Diffusion and reaction kinetics, Viscosity and film forming characteristics
• Is a thermoplastic or thermoset (crosslinked) characteristic desired?
• Is architecture (branched, linear, star, etc.) important?
• How would this material be processed into its final product?
• How does your chosen approach compare to other possible approaches?

Scoring

Maximum of 5 points per category: Total maximum is 25 points

1. Understanding of Subject Matter
2. General Referencing (Depth and Accuracy)
3. Description of Polymer Synthetic Route
4. Design Concepts - Creativity
5. Design Concepts - Feasibility