Project Description

Microstructure of Inter-Penetrating Polymers

Biomodics and the University of Copenhagen have used a new variant of neutron scattering to determine the structure of hydrogel polymer networks at a much longer length scale.

Biomodics have developed an innovative method to introduce a hydrophilic polymer gel, called a hydrogel, into silicone medical devices. When used in a clinical setting, these devices reduce the formation of the biofilms that frequently result in infection and are also being developed as a way to controllably release drugs to patients.

Read the interesting one pager from this project: Micrometer structure of interpenetrating polymer networks.

Techniques and Methods

The LINX team at the University of Copenhagen (KU) has previously worked with Biomodics using small-angle neutron scattering (SANS) to calculate the important length scales of the hydrogel network located throughout the interpenetrating polymer network (IPN). This provided confirmation of the IPN structure of the devices. The SANS technique is limited to measuring sizes of a few hundred nanometres, and the shortest length scale that Biomodics had been able to visualize using microscopy was on the order of several micrometres, at least ten times greater. IPNs are, by nature, a hierarchical structure, therefore structures at any length scale may be important.

To bridge this gap, the LINX team at KU employed a new variant of neutron scattering called spin-echo small-angle neutron scattering (SESANS). Being a neutron scattering technique, the same trick was used as in the previous project to gain contrast between the hydrogel and the silicone: the IPN was hydrated in heavy water (D2O). The primary advantage of SESANS over conventional SANS is that the range of sizes that can be studied is much greater, up from around 100 nanometres to 16 micrometres. These measurements revealed that there were structures in the materials of nearly a micrometre that otherwise could not have been detected, being too large for SANS and too small for most microscopy techniques.

Project Information

Participants: Biomodics, University of Copenhagen.
Start date, end date:
October 2018 – December 2018.
Title:
Micron scale structure of interpenetrating polymer networks studied with SESANS (FP04.004, Colloid materials).