As a laser processing based research group, nearly all of our research is primarily focused on the generation of structures on different surfaces. We process all kinds of materials from common thermoplastic polymers, metals and glasses. To advanced alloys, semiconductors and ceramics. By generating micro- and nanostructured surfaces it possible to improve or change a multitude of different properties from their interaction with light (i.e. absorption, reflectance and optical scattering), to their adhesive properties, their electrical conductance and resistance to wear. Lasers in particular offer a highly repeatable, highly controllable, and highly scalable tool to manipulate surface properties.

Because of this, micro- and nanostructured surfaces based have seen usage in a wide range of applications. This includes optics, medical devices, self-cleaning surfaces, microfluidics, sensing and electronic devices.

For more information on our research into applying surface structuring to the investigation of wetting and microbiological control, please see the relevant tabs.


For more details or to work with us please e-mail: s.hodgson@chester.ac.uk

Wetting science has been around for centuries and relates to the angle a liquid droplet presents when placed on a surface (low being hydrophilic (wetting) and high being hydrophobic (non-wetting). The steps towards it’s currently recognizable form were taken in the 1800s with the development of the Young equation. By the end of World War 2 the two models most commonly referred to in Wetting today, the Wenzel and Cassie-Baxter models, had been developed. As may be expected, neither of these models tell the whole story and wetting research over the last 20-30 years has focused on developing the understanding of the transition between the two models, how liquids behave in what is called the mixed-state (i.e. somewhere between the two), and the relationship between surface roughness and texture and the contact angle produced. Also, particularly recently, the ability to produce superhydrophobic surfaces (contact angle greater than 150°) has come to the fore. As a group we are not only interested in studying the relationship between the relationships between surface texture, roughness, chemical composition and their relationship with wetting and adhesion models but we also attempt to relate this to how microorganisms such as bacteria interact with surfaces. As a laser-focused research group, we are able to subject materials to highly energetic conditions and create a range of surface structures that influence the material’s interaction with liquids.


For more details or to work with us please e-mail: s.hodgson@chester.ac.uk

Bacterial biofilm growth can be a huge problem in food and medical industries. The growth of bacteria on surfaces can lead to infection, disease and, in the most extreme cases, even death. The ability to influence the growth of bacteria on a surface, either promoting or inhibiting attachment as required, is of growing interest. By studying the structural, chemical and energetic properties of surfaces it is becoming more and more possible to understand the mechanisms that bacteria use to attach to surfaces.


For more details or to work with us please e-mail: s.hodgson@chester.ac.uk

At the laser lab we are interested in exploring the generation of nano- and microstructures in optically transparent materials for the purpose of scattering light in favorable ways. This has particular application for Photovoltaics (PV) which is one of the most prominent forms of renewable energy in the world today. Many options are being explored to enhance the performance of PV devices, and any way to enhance the absorption of light in a cell can be considered advantageous. We particularly focus on applying our work on to 2nd and 3rd generation PV devices.


For more details or to work with us please e-mail: s.hodgson@chester.ac.uk

Laser shock peening (LSP) has been around since the late 1960s and is a technique by which materials can be strengthened, hardened and have their resistance to wear improved by using high powered lasers to generate shock-waves in a similar manner to mechanical shot-peening albeit one that is contactless. LSP creates beneficial residual stresses in materials, most commonly metals and alloys, by inducing plastic deformation in the material. At the Laser Lab we are interested in exploring the laser-materials interactions involved in peening with particular application to metals and alloys.


For more details or to work with us please e-mail: s.hodgson@chester.ac.uk

A laser processing modelling capability is being established by Dr Gerard Edwards at the University of Chester to guide, assist and inform the experimental efforts.

Dr Edwards has been recently involved with providing theoretical and computer modelling/simulation support to assist the interpretation of cone calorimeter experimental results for composite material burning. This modelling work entails a multi-physics solution of the Henderson model for the combustion of composite materials using the Finite Element Method. This multi-physics problem consists of three coupled partial differential equations (PDEs): (i) The heat conduction in the composite (including the cone radiation heat source); (ii) the Arrhenius equation describing the progress of the chemical reaction; and (iii) the conversation of mass equation, describing the flow of the volatile gas (produced by the decomposition of the composite). He intends to bring this heat and mass transfer modelling experience to bear in the field of laser materials processing and to use Green’s functions techniques, acquired during his earlier work as a theoretical semiconductor physicist. The use of advanced theoretical techniques will allow a fuller description of the underlying physics of laser materials processing and thus inform the direction of future research.

Preliminary work has been carried out to extend the materials processing routines of the MATLAB Laser Toolbox [https://www.utwente.nl/en/et/ms3/research-chairs/lp/Matlab%20Laser%20Toolbox/#introduction] which just solve the heat conduction equation, to incorporate the physics of melting so essential to describing laser cutting, drilling or welding.

Initially a 1D melting model has been established which solves the transcendental equations (obtained from applying the boundary conditions) and plots both

  • the melting front versus time and
  • the temperature versus position for increasing time on the same axes

for a slab of ice, initially at zero temperature, subjected to a 10 oC ‘heat excitation’ on the left hand side, at time zero. The melting front and increase in temperature in the slab at later times are shown in the simulation results below.

The melting front for a semi-infinite slab of ice for x > 0 which at t = 0 has the temperature raised to T(x = 0) = 10 Celsius.

The temperature (T) against x for increasing time, for a semi-infinite slab of ice for x > 0 which at t = 0 has the temperature raised to T(x = 0) = 10 Celsius.

We are in the process of extending this model to 2D/3D and also incorporating the movement of the laser through the work piece.


For more details or to work with us please e-mail: s.hodgson@chester.ac.uk

Journal Papers

Here is a summary of our recently published work involving the use of laser processing. For information on non-laser focused papers please see each lab member’s individual google scholar page.

2018

  1. CW Chan, L Carson, GC Smith, Fibre laser treatment of martensitic NiTi alloys for load-bearing implant applications: Effects of surface chemistry on inhibiting Staphylococcus aureus biofilm formation, Surface and Coatings Technology, 349, 488-502
  2. CW Chan, GC Smith, S Lee, “A Preliminary Study to Enhance the Tribological Performance of CoCrMo Alloy by Fibre Laser Remelting for Articular Joint Implant Applications”, Lubricants 6 (1), 24

2017

  1. CW Chan, L Carson, GC Smith, A Morelli, S Lee, “Enhancing the antibacterial performance of orthopaedic implant materials by fibre laser surface engineering”, Applied Surface Science 404, 67-81
  2. CH Ng, CW Chan, HC Man, DG Waugh, J Lawrence, “NiTi shape memory alloy with enhanced wear performance by laser selective area nitriding for orthopaedic applications”, Surface and Coatings technology, 309, 1015-1022
  3. CW Chan, S Lee, GC Smith, C Donaghy, “Fibre laser nitriding of titanium and its alloy in open atmosphere for orthopaedic implant applications: Investigations on surface quality, microstructure and tribological properties”, Surface and Coatings Technology 309, 628-640

2016

  1. A Gillett, D Waugh, J Lawrence, M Swainson, R Dixon, “Laser surface modification for the prevention of biofouling by infection causing Escherichia Coli.”, Journal of Laser Applications 28 (2), 022503
  2. SD Hodgson, DG Waugh, A Gillett, J Lawrence, “High speed CO2 laser surface modification of iron/cobalt co-doped boroaluminosilicate glass and the impact on surface roughness, gloss and wettability”, Laser Physics Letters, 13 (7), 076102
  3. CW Chan, S Lee, G Smith, G Sarri, CH Ng, A Sharba, HC Man, “Enhancement of wear and corrosion resistance of beta-titanium alloy by laser gas alloying with nitrogen”, Applied Surface Science 367, 80-90
  4. DG Waugh, C Toccaceli, AR Gillett, CH Ng, SD Hodgson, J Lawrence, “Surface treatments to modulate bioadhesion: a critical review”, Reviews of Adhesion and Adhesives 4 (1), 69-103
  5. CW Chan, GC Smith, “Fibre laser joining of highly dissimilar materials: commercially pure Ti and PET hybrid joint for medical device applications”, Materials & Design 103, 278-292
  6. G Kartopu, LJ Phillips, V Barrioz, SJC Irvine, SD Hodgson, E Tejedor, D Dupin, AJ Clayton, SL Rugen‐Hankey, K Durose, “Progression of metalorganic chemical vapour deposited CdTe thin-film PV devices towards modules”, Progress in Photovoltaics: Research and Applications 24 (3), 283-291, 2016
  7. DG Waugh, I Hussain, J Lawrence, GC Smith, D Cosgrove, C Toccaceli, “In vitro mesenchymal stem cell response to CO2 laser modified polymeric material”, Materials Science and Engineering: C 67, 727-736

Conferences & Events

2017

  1. SN Baxter, K Besecke, SD Hodgson, AR Gillett, PJ Thomas, “Nanocrystalline films of metal & metal alloys at the water-oil interface”, 13th International Conference on Materials Chemistry P.384, July, 2017, Liverpool, UK
  2. C Albinet, A Platt, C Swanson, S Hodgson, “Improving the mechanical properties of biodegradable copolymer poly-(l-lactide)-polyglycolide incorporated with layered double hydroxides”, July, 2017, Liverpool, UK
  3. SD Hodgson, AR Gillett, “Laser surface engineering at Chester: capabilities and applications”, RSC Young Scientist Symposium, July, 2017, Wrexham, UK.
  4. SN Baxter, K Besecke, SD Hodgson, AR Gillett, PJ Thomas, “Nanocrystalline films of metal & metal alloys at the water-oil interface”, RSC Young Scientist Symposium, July, 2017, Wrexham, UK

2016

  1. AR Gillett, DG Waugh, GC Smith, SD Hodgson, J Lawrence, “Laser surface engineering to modulate wettability characteristics and conditioning film formation on polyethylene terephthalate (PET) and the subsequent effect on E. coli biofilm formation”, NYAS and PepsiCo Innovation Day, November, 2016, New York, NY, USA.

2015

  1. CH Ng, CW Chan, HC Man, D Waugh, J Lawrence, G Smith, “Novel Laser Technology to Enhance the Wear Resistance of Shape Memory NiTi Alloy for Total Joint Replacement Applications”, Journey through Science Day, December 14, 2015, New York, USA
  2. AR Gillett, DG Waugh, J Lawrence, “Influencing the attachment of bacteria through laser surface engineering”, 34th International Congress on Application of Lasers & Electro-Optics (ICALEO), October 18-22, 2015, Atlanta, GA, USA
  3. CH Ng, CW Chan, HC Man, D Waugh, J Lawrence, “Modifications of Surface Properties of Beta Ti by Laser Surface Treatment”, 34th International Congress on Applications of Laser & Electro-Optics (ICALEO), October 18-22, 2015, Atlanta, USA
  4. AR Gillett, DG Waugh, J Lawrence, M Swainson, RA Dixon, “Laser surface engineering to modulate wettability characteristics and conditioning film formation on polyethylene terethphlate (PET) and subsequent effect on E. coli biofilm formation”, UK Surface Analysis Forum, 2015 July, Chester, UK

Books & Chapters

2017

  1. DG Waugh, C Toccaceli, AR Gillett, CH Ng, SD Hodgson, J Lawrence, “Surface treatments to modulate bioadhesion”, Progress in Adhesion and Adhesives: Volume 2, 67-114.

2016

  1. A. Gillett, D.G. Waugh, J. Lawrence, “Laser surface modification of polymeric surfaces for microbiological applications”, Laser Surface Modification of Biomaterials: Techniques and Applications, 197-220

For more details or to work with us please e-mail: s.hodgson@chester.ac.uk