Research Areas

The group's interests primarily lie in polymer chemistry. We interested in a host of polymer-related technologies, ranging from biomaterials, nanocomposites, polymer photochemistry, and living radical polymerization techniques such as ATRP, RAFT and NMP. More details can be found below.

Research Areas

The primary goal of the proposed research is to develop new polymer – layered silicate nanocomposite materials. While polymer – layered silicate nanocomposites have been investigated over the past 15 years a major restriction has been in the degree of control that can be achieved in terms of the polymer molecular weight, polydispersity, functionality, composition and topology. We are developing procedures to produce nanocomposites that are well-defined in each of these aspects. These novel methods will not only allow the development of new and improved materials, but also allow for an in depth investigation into the dispersion of the clay within the polymer matrix.

Polymer Nanocomposites

There has been several new polymerization techniques that have been developed in recent years, including atom transfer radical polymerization (ATRP), reversible addition-fragmentation chain transfer (RAFT) polymerization and nitroxide-mediated polymerization (NMP). Each of these methods are free radical based polymerizations, thus making them amenable to the polymerization of a variety of monomers under non-strenuous reaction conditions. They also have the capability of synthesizing a large range of polymer architectures. However, there are many questions that remain about mechanisms and reaction rates. Work in our group is examining what factors affect the mechanism and kinetic parameters, as well as looking into alternate methods of controlling polymerizations.

Living Radical Polymerizations

New biocompatible and biodegradable materials are continually needed in several areas for medical use, for example, in drug delivery, therapeutic devices and gene therapy/delivery. The most common materials currently used for such applications have been degradable polyesters, including poly (L-lactic acid), poly(glycolic acid), and poly(lactic-co-glycolic acid). However, these polyesters have quite slow degradation rates, and often lack many properties necessary for medical applications such as homogeneous bulk degradation, which is detrimental to the long-term mechanical properties of the material. Surface eroding polymers, such as polyanhydrides, maintain their mechanical integrity during degradation and exhibit a gradual loss in size.

In this project we have shown that thiol-ene chemistry, a step-growth mechanism of polymerization, can be applied to make materials that are elastomeric, photocurable and have controllable degradation rates, starting from only several hours. Thiol-ene chemistry is also quite simple and has readily available monomers, and the degradable functionality resides in the main chain, rather than a side chain, which reduces the molecular weight of the degradation products compared to chain growth polymerizations. Thus, using thiol-ene chemistry to make polyanhydride network polymers provides significant flexibility in tailoring characteristics such as crosslink density, functionality and hydrophilicity.

Novel Degradable Polymers

Research Group of Prof. Devon A. Shipp

Polymers @ Clarkson University

Dr. Shipp and graduate student Qin Lou examine a conducting glass electrode with nanostructured TiO₂ particles patterned on it.

We are particularly interested in using polymers to pattern TiO₂ nanoparticles onto conducting glass—these materials may find use in dye-sensitized solar cells and other photovoltaic devices. Our approach is outlined in the scheme below.

Nanocomposites for Photovoltaic Devices

Working with a major eye-care company, we are developing new contact lens materials that will allow the both oxygen and water to permeate to/from the eye. Our expertise in living radical polymerizations allow us to make these new polymers with a high degree of molecular weight and functionality control.

Polymers for Ophthalmic Applications