The Quartz Crystal Microbalance with Dissipation (QCM-D) is an extremely sensitive balance that is primarily used to study surfaces and interfaces of materials over a wide range of areas. It detects a change in mass on a surface by monitoring the changes in frequency of the quartz crystal during operation. It determines whether the mass attached to a surface is soft or rigid by monitoring the energy loss (or ‘dissipation’) of the crystal during a change in its frequency. This state-of-the-art scientific instrument provides important information on how materials interact with each other at interfaces, and has allowed researchers at the University of Mississippi (UM) to progress their research in many areas of novel material development. Three of the key areas are:

1. Sustainable packaging: Research in Chemical Engineering is underway to produce water-repellent paper packaging using sustainable waxes that can be easily removed from the paper after use for recycling purposes. QCM-D studies have identified several waxes which strongly attach to the cellulose surface. Some of these are easily removed upon a simple flushing process, while others are firmly attached to the paper surface. From a sustainability viewpoint, those that are more easily removed would be more suitable to reuse both the wax and the paper upon recycle. Waxes investigated to date include alkyl ketene dimer (AKD) and carnauba wax.
2. Membrane development for water treatment: Both industry and residential communities depend on effective water treatment to negate and remove harmful contaminants. Membrane-based separation processes are widely used for their efficiency in contaminant removal, but these membranes often face challenges such as fouling during operation. To better understand these fouling mechanisms, QCM-D was employed to study the surface interactions on ion exchange membranes. Furthermore, a novel technique for creating model ion exchange membrane QCM-D sensors was developed and validated through fouling studies. The results demonstrated that the newly developed membranes effectively simulated surface interactions that occur during reversible and irreversible fouling processes.
3. Cardiovascular health: Muscle contraction of the heart is critical in its normal functioning, and myosin II motor proteins drive the heart muscle contraction.  The QCM-D was used to investigate how myosin motors alter muscle stiffness and how this work at the molecular level scales up to facilitate contraction. Understanding the interplay between myosin and muscle contraction is necessary for understanding how muscles function normally, react to stress, and respond to drugs used to treat heart disease.

These three study areas have obvious, positive, societal impacts. Developing sustainable packaging using sustainable materials that can be recycled for re-use assists in minimizing environmental harm and use of toxic chemicals. Improvements in membrane material development promotes better water treatment methods with longer-lasting membranes. Finally, understanding the mechanisms of maintaining a healthy heart has huge implications on societal health. In all these cases, advanced knowledge was possible by studying the interfaces of connecting surfaces with the QCM-D, and has greatly assisted in overall material development and enhanced healthcare options for the future.

Besides the longer-term societal impacts expected from this work, a considerable number of students have participated in learning experiences involving the QCM-D. Two 500-level courses involving an average of approximately 15 students in each class have studied the theory and importance of surfaces/interfaces as well as participated in laboratory demonstrations. These courses are a combination of both graduate and undergraduate students, and are regularly taught in the academic curriculum. In every year of this grant, summer research programs for undergraduate students and high school students have utilized this instrument, where several students became proficient in its operation to participate in some of the studies described. As a research tool, several research groups (graduate and undergraduate students) have routinely used the QCM-D to pursue their research objectives, and write up their work in the form of posters, conference presentations, and literature articles. This state-of-the-art instrument has become a much utilized tool for material development and mechanistic research.

Last Modified: 10/31/2024
Modified by: Brenda H Prager