|
Macromolecular Complex Systems
The overall
goal of this program is to develop a fundamental understanding of how
the chemical composition and the molecular and supramolecular
architecture of stimuli-responsive polymers impacts their physical and
chemical properties. Stimuli-responsive polymers are those that undergo
a dramatic physical or chemical change in response to a small change
in their environment. These polymers are
currently of tremendous interest because they can mimic the properties
of biopolymers found in living organisms, and they can lead to new (biocompatible)
materials whose properties can be precisely controlled by external stimuli.
However, there currently is a lack of understanding of how the chemical
composition and molecular architecture of stimuli-responsive polymers
affect their properties.
To address these issues, the specific aims of this program are:
- to synthesize well-defined synthetic polypeptides and study their
properties as a function of chemical composition, architecture,
and environment, in order to gain insights into biological systems
and
the design of biomimetic materials;
- to synthesize and study
the thermal response and properties of novel PEGylated acrylate-,
ethacrylate-, and thiophene-containing
polymers
and copolymers in order to learn how structure affects properties;
and
- to design, synthesize and characterize stimuli-responsive
nanoporous polymer membranes as biomimetic membranes.
In
order to predict and control the self-assembly and response of these
macromolecules, it is necessary to tailor the materials
using rigorous
synthetic techniques to control their chemical nature,
molecular weight, macromolecular architecture, and positioning of monomer
units, as well
as build in specific interactions. We will utilize our expertise in the controlled synthesis of well-defined
polymer and copolymer architectures by anionic and controlled radical
polymerization techniques to design and synthesize well-defined stimuli-responsive
polymers based on biocompatible materials, i.e., amino acids and oligo(ethylene
glycols). We will rigorously characterize these polymers by spectroscopic,
chromatographic, thermal and mechanical, and scattering (light, X-rays
and neutron) techniques and study their self-assembly in solution, at
interfaces, and in the bulk. The response of these polymers to external
stimuli, such as temperature, pH, solvent polarity and ionic strength,
will be studied in solution and on surfaces in order to determine structure-property
relationships, thereby engendering the opportunity to rationally design
and tune the properties of the next-generation materials. We will explore
new synthetic techniques to control the sequence of amino acids in large
polypeptide chains from the anionic polymerization of amino acid N-carboxyanhydrides
in order to control primary and secondary structure and function. Surface
polymerization techniques will be developed to grow well-defined polypeptide
brushes from model surfaces to study their interfacial properties and
the impact of short peptide chains that engenders a specific binding
functionality will be probed. Thermally responsive water-soluble polymers
and copolymers based on oligo(ethylene glycol) substituted acrylates,
methacrylates, and thiophenes will be studied in solution and on surfaces
as a function of molecular weight and chemical composition to determine
how structure affects aggregation and their thermal response. Finally,
we will utilize the knowledge gained to synthesize nanoporous membranes
containing heat or pH responsive polymers and investigate the controlled
permeation of liquids through the pores.
This comprehensive program will provide a better understanding of the
structure-property relationships of stimuli-responsive polymers, thereby
significantly advancing the goal of developing novel materials that mimic
the properties and functions of biopolymers.
Capabilities for
User Research in Macromolecular Complex Systems
|
