Dr Karen Johnston
Reader
Chemical and Process Engineering
Personal statement
My group models a range of materials using multiscale simulations including sustainable plastics, polymer thin films and composites, molecular crystals, solid-liquid interfaces and oxide materials. In these systems the interfacial properties are crucial in understanding and controlling the system, for example, heterogeneous crystal nucleation of polymer or small molecule systems. We have a broad interest in materials science and engineering and enjoy collaborating with experimentalists and industrial partners. For more information please visit my group webpage.
Area of Expertise
Density functional theory (DFT): electronic structure, adsorption and surface energies, vibrational frequencies etc.
Molecular dynamics (MD) simulations: structure and dynamics of thin films, liquids, solutions, solids etc. using all-atom and/or coarse-grained force fields.
Prize And Awards
- Strathclyde Team Award
- Recipient
- 2019
Qualifications
Member of the Institute of Physics
Fellow of the Higher Education Academy
Member of the Scottish Plastics and Rubber Association
Publications
- Uncovering the vibrational modes of zwitterion glycine in aqueous solution
- Christie Mark, Mohammadpour Mozhdeh, Sefcik Jan, Faulds Karen, Johnston Karen
- Vibrational Spectroscopy Vol 137 (2025)
- https://doi.org/10.1016/j.vibspec.2025.103783
- Molecular dynamics study of chitosan adsorption at a silica surface
- Hudek Magdalena, Johnston Karen, Kubiak-Ossowska Karina, Ferro Valerie A, Mulheran Paul A
- The Journal of Physical Chemistry C Vol 128, pp. 21531-21538 (2024)
- https://doi.org/10.1021/acs.jpcc.4c05821
- The impact of plasticisers on crystal nucleation, growth and melting in linear polymers
- Wadkin-Snaith Dominic, Mulheran Paul A, Johnston Karen
- Polymer Vol 304 (2024)
- https://doi.org/10.1016/j.polymer.2024.127095
- Assessment of GAFF and OPLS force fields for urea : crystal and aqueous solution properties
- Anker Samira, McKechnie David, Mulheran Paul, Sefcik Jan, Johnston Karen
- Crystal Growth and Design Vol 24, pp. 143–158 (2024)
- https://doi.org/10.1021/acs.cgd.3c00785
- Crystallisation of sodium sulfate
- Muhammad Abdullah, Sefcik Jan, Hamilton Andrea, Johnston Karen
- ISIC 2023 (2023)
- Investigation of vibrational changes due to adsorption of glycine on gold
- Mohammadpour Mozhdeh, Johnston Karen
- Computational and Theoretical Chemistry Vol 1227 (2023)
- https://doi.org/10.1016/j.comptc.2023.114224
Teaching
My teaching philosophy is to provide the best learning environment by challenging students through providing questions related to everyday exampes, that develop student's understanding and problem solving skills.
I am the course organiser and a lecturer for CP102 Introduction to Chemical Engineering: Fundamentals, Techniques and Tools, and the distance learning course CP108 Mathematics for Chemical Engineers. I also supervise CP407 design projects and 18350 MEng projects.
Research Interests
Polymers
The properties of polymer composites are dependent on the interface between the polymer and surface. We have developed multiscale models to explore how surfaces affect the polymer properties, such as melt structure, glass transition and crystallisation. We also study sustainably-sourced and compostable polymers including polyhydroxyalkanoates, alginates and chitin/chitosan. We are investigating how the addition of filler particles and plasticisers may help to improve the properties, leading to uptake of sustainable plastics in applications such as food packaging.
Heterogeneous Nucleation
Nucleation mainly occurs via heterogeneous mechanisms, with the nucleus forming on a surface or interface, rather than in bulk solution. We use molecular dynamics simulations to study the composition, structure and dynamics of the solution at the interface region, which can have significantly different properties than in the bulk region.
Adsorption and self-assembly
Adsorption of molecules to surfaces is important in a wide range of systems, including soft-hard matter interfaces, and self-assembly. We use quantum density functional theory to study the adsorption of molecules onto surfaces.
Force field optimisation
To model systems using classical MD it is crucial to have a force field that accurately describes the behaviour of the system. In interfacial systems the interaction at the interface is particularly important but experimental information is not often available. We use quantum density functional theory calculations to optimise interface force fields. For crystallising systems the force field should describe both crystal and amorphous/solution phases. We validate force field to describe both phases based on available data.
Professional Activities
- Strategic Themes - EPSRC (Critical Mass) - Sustainable & Circular Materials & Manufacturing
- Participant
- 11/2/2025
- Departmental Seminar
- Speaker
- 5/2/2025
- External examiner for PhD thesis defence
- Examiner
- 22/11/2024
- Institute of Physics (External organisation)
- Advisor
- 1/10/2024
- Physical Aspects of Polymer Science 2024
- Speaker
- 9/9/2024
- CCP5 Annual General meeting
- Speaker
- 4/9/2024
Projects
- Modelling polylactone crystallisation (AKT Ingevity)
- Johnston, Karen (Principal Investigator) Mulheran, Paul (Academic)
- 25-Jan-2024 - 23-Jan-2024
- Sustainable plastics for bathroom products
- Zhang, Xiaolei (Principal Investigator) Johnston, Karen (Principal Investigator)
- 01-Jan-2022 - 30-Jan-2022
- IBioIC CTP PhD studentship Optimisation of alginate films for sustainable food packaging applications
- Johnston, Karen (Principal Investigator) Mulheran, Paul (Co-investigator)
- 01-Jan-2021 - 30-Jan-2025
- ISCF - Biocomposite design for food packaging
- Johnston, Karen (Principal Investigator) Liggat, John (Co-investigator) Mulheran, Paul (Co-investigator) Magueijo, Vitor (Researcher)
- 01-Jan-2020 - 30-Jan-2024
- Doctoral Training Partnership 2020-2021 University of Strathclyde | Anker, Samira
- Johnston, Karen (Principal Investigator) Sefcik, Jan (Co-investigator) Anker, Samira (Research Co-investigator)
- 01-Jan-2020 - 14-Jan-2025
- Design of functional chitosan films: antimicrobial and heavy metal capture applications
- Mulheran, Paul (Principal Investigator) Ferro, Valerie (Co-investigator) Johnston, Karen (Co-investigator)
- 01-Jan-2020 - 30-Jan-2024
Contact
Dr
Karen
Johnston
Reader
Chemical and Process Engineering
Email: karen.johnston@strath.ac.uk
Tel: Unlisted