Evaporative Drying of Droplets and the Formation of Micro-structured and Functional Particles
Lead Research Organisation:
University of Bristol
Department Name: Chemistry
Abstract
The drying of liquid droplets is a complex process with a wealth of dynamics occurring inside the liquid phase. The effect of these internal processes is to change the distribution of materials in the particle that is formed after drying. These processes are important in a wide range of applications from spray drying processes that form functionalised and micro-structured particles, crop spraying and to the dynamics of particles during inhalation therapies. In this project we will explore the drying kinetics of isolated droplets in air using a range of unique single particle experimental tools. In particular, measurements will use an electrodynamic balance to directly probe the time-evolving size and morphology of droplets during drying with time-resolution as high as 10 ms. The steady equilibrium viscosity and surface tensions of droplets will be interrogated with varying droplet composition using aerosol optical tweezers. We will seek to understand how droplets dry and provide a quantitative approach to measure, predict and interpret the dynamics of droplet evaporation. For example, we will address questions such as when do you get a solid particle or a hollow particle, a uniform particle or one with shells? When formed, are the particles crystalline or amorphous, are different components mixed or separated?
Organisations
- University of Bristol (Lead Research Organisation)
- Centre for Process Innovation (CPI) (Collaboration)
- Danone (Collaboration)
- Nestlé (Global) (Collaboration)
- AkzoNobel (Collaboration)
- Syngenta International AG (Collaboration)
- DURHAM UNIVERSITY (Collaboration)
- Sun Chemical Ltd (Collaboration)
- Croda International (Collaboration)
- Bristol-Myers Squibb (Collaboration)
- UNIVERSITY OF LEEDS (Collaboration)
- Chiesi (Collaboration)
- Inca Digital Printers Ltd (Collaboration)
- University of Alberta (Collaboration)
- University of Bristol (Collaboration)
People |
ORCID iD |
Jonathan Reid (Primary Supervisor) | |
Florence Gregson (Student) |
Publications
Gregson FKA
(2019)
Studies of competing evaporation rates of multiple volatile components from a single binary-component aerosol droplet.
in Physical chemistry chemical physics : PCCP
Gregson FKA
(2019)
Drying Kinetics of Salt Solution Droplets: Water Evaporation Rates and Crystallization.
in The journal of physical chemistry. B
Ordoubadi M
(2019)
Multi-Solvent Microdroplet Evaporation: Modeling and Measurement of Spray-Drying Kinetics with Inhalable Pharmaceutics.
in Pharmaceutical research
Studentship Projects
Project Reference | Relationship | Related To | Start | End | Student Name |
---|---|---|---|---|---|
EP/N509619/1 | 30/09/2016 | 29/09/2021 | |||
1793186 | Studentship | EP/N509619/1 | 30/09/2016 | 30/03/2020 | Florence Gregson |
Description | We have studied particle formation in rapidly evaporating aerosol droplets: aqueous droplets containing solutions of inorganic or organic solutes or mixtures. We studied how evaporation rates vary depending on the processing conditions, and how this can strongly affect the crystallisation of inorganic components. For example, with sodium chloride droplets, low concentrations of droplets evaporating into high temperatures evaporate much quicker than high concentrations or lower temperatures, and significant surface enrichment can occur at the droplet surface. This leads to highly monodisperse, hollow, crystalline particles. Alternatively, other solutions such as sodium nitrate, evaporate in a highly non-reproducible fashion with some droplets crystallising and others forming amorphous particles. By tuning the drying temperature, humidity, concentration of sodium nitrate, and the presence of additional co-components, we can predict and control the degree of crystalline or amorphous particles formed. This is very useful for those in the spray-drying field to be able to better control their product morphology for a desired application. |
Exploitation Route | In the field of spray-drying, it is crucial to be able to control the product morphology of the powder particles. Some applications may need a highly crystalline product, or a very soluble product, or a very low density (for e.g. good aerodynamic properties for lung delivery of pharmaceutical powdered drugs). Industrial partners will be able to take our findings to better understand particle formation in their spray-dryers to hence fine-tune their drying conditions for a desired powdered product. In the wider sense, knowledge about the mechanisms behind particle formation from liquid droplets is highly useful for producing particles for fuel cell applications, for agricultural crop-spraying, and inkjet printing. |
Sectors | Agriculture Food and Drink Manufacturing including Industrial Biotechology Pharmaceuticals and Medical Biotechnology |
Description | Our findings lead to some collaborators in industrial sectors (such as spray-drying companies, crop-spraying, pharmaceutical and inkjet printing) to better understand how their droplets evaporate under different conditions to lead to better product control. In addition, we performed some work on how rapid volatile solvents evaporate under humid atmospheres which is highly useful for inhaler technology. We reported these findings at various conferences and meetings and some pharmaceutical companies were very interested in this work. |
First Year Of Impact | 2017 |
Sector | Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology |
Impact Types | Economic |
Description | Collaboration about droplet drying: comparison between spray dryers and droplets on surfaces |
Organisation | AkzoNobel |
Country | Netherlands |
Sector | Private |
PI Contribution | We take measurements on droplets drying in free air (levitated) using our instrumentation and regularly report our results to our partners at collaborative meetings. |
Collaborator Contribution | Our university collaborators take measurements of droplets drying on flat surfaces or of modelled droplets in spray-dryers and compare their results with ours at collaborative meetings. The industrial partners attend these meetings to discuss our results and comment on any issues in their processes which we could investigate in experimental measurements. Occasionally our industrial partners provide us with their own materials (e.g. milk powder, paint) for us to study droplet drying with in our instruments. |
Impact | This collaborative partnership has led to useful sharing of ideas and solving experimental problems. It also gives us direction about what interesting systems to try in our experiments so that we can better compare our results. |
Start Year | 2016 |
Description | Collaboration about droplet drying: comparison between spray dryers and droplets on surfaces |
Organisation | Bristol-Myers Squibb |
Country | United States |
Sector | Private |
PI Contribution | We take measurements on droplets drying in free air (levitated) using our instrumentation and regularly report our results to our partners at collaborative meetings. |
Collaborator Contribution | Our university collaborators take measurements of droplets drying on flat surfaces or of modelled droplets in spray-dryers and compare their results with ours at collaborative meetings. The industrial partners attend these meetings to discuss our results and comment on any issues in their processes which we could investigate in experimental measurements. Occasionally our industrial partners provide us with their own materials (e.g. milk powder, paint) for us to study droplet drying with in our instruments. |
Impact | This collaborative partnership has led to useful sharing of ideas and solving experimental problems. It also gives us direction about what interesting systems to try in our experiments so that we can better compare our results. |
Start Year | 2016 |
Description | Collaboration about droplet drying: comparison between spray dryers and droplets on surfaces |
Organisation | Centre for Process Innovation (CPI) |
Country | United Kingdom |
Sector | Private |
PI Contribution | We take measurements on droplets drying in free air (levitated) using our instrumentation and regularly report our results to our partners at collaborative meetings. |
Collaborator Contribution | Our university collaborators take measurements of droplets drying on flat surfaces or of modelled droplets in spray-dryers and compare their results with ours at collaborative meetings. The industrial partners attend these meetings to discuss our results and comment on any issues in their processes which we could investigate in experimental measurements. Occasionally our industrial partners provide us with their own materials (e.g. milk powder, paint) for us to study droplet drying with in our instruments. |
Impact | This collaborative partnership has led to useful sharing of ideas and solving experimental problems. It also gives us direction about what interesting systems to try in our experiments so that we can better compare our results. |
Start Year | 2016 |
Description | Collaboration about droplet drying: comparison between spray dryers and droplets on surfaces |
Organisation | Chiesi |
Country | Italy |
Sector | Private |
PI Contribution | We take measurements on droplets drying in free air (levitated) using our instrumentation and regularly report our results to our partners at collaborative meetings. |
Collaborator Contribution | Our university collaborators take measurements of droplets drying on flat surfaces or of modelled droplets in spray-dryers and compare their results with ours at collaborative meetings. The industrial partners attend these meetings to discuss our results and comment on any issues in their processes which we could investigate in experimental measurements. Occasionally our industrial partners provide us with their own materials (e.g. milk powder, paint) for us to study droplet drying with in our instruments. |
Impact | This collaborative partnership has led to useful sharing of ideas and solving experimental problems. It also gives us direction about what interesting systems to try in our experiments so that we can better compare our results. |
Start Year | 2016 |
Description | Collaboration about droplet drying: comparison between spray dryers and droplets on surfaces |
Organisation | Croda International |
Country | United Kingdom |
Sector | Private |
PI Contribution | We take measurements on droplets drying in free air (levitated) using our instrumentation and regularly report our results to our partners at collaborative meetings. |
Collaborator Contribution | Our university collaborators take measurements of droplets drying on flat surfaces or of modelled droplets in spray-dryers and compare their results with ours at collaborative meetings. The industrial partners attend these meetings to discuss our results and comment on any issues in their processes which we could investigate in experimental measurements. Occasionally our industrial partners provide us with their own materials (e.g. milk powder, paint) for us to study droplet drying with in our instruments. |
Impact | This collaborative partnership has led to useful sharing of ideas and solving experimental problems. It also gives us direction about what interesting systems to try in our experiments so that we can better compare our results. |
Start Year | 2016 |
Description | Collaboration about droplet drying: comparison between spray dryers and droplets on surfaces |
Organisation | Danone |
Department | Nutricia Ltd |
Country | United Kingdom |
Sector | Private |
PI Contribution | We take measurements on droplets drying in free air (levitated) using our instrumentation and regularly report our results to our partners at collaborative meetings. |
Collaborator Contribution | Our university collaborators take measurements of droplets drying on flat surfaces or of modelled droplets in spray-dryers and compare their results with ours at collaborative meetings. The industrial partners attend these meetings to discuss our results and comment on any issues in their processes which we could investigate in experimental measurements. Occasionally our industrial partners provide us with their own materials (e.g. milk powder, paint) for us to study droplet drying with in our instruments. |
Impact | This collaborative partnership has led to useful sharing of ideas and solving experimental problems. It also gives us direction about what interesting systems to try in our experiments so that we can better compare our results. |
Start Year | 2016 |
Description | Collaboration about droplet drying: comparison between spray dryers and droplets on surfaces |
Organisation | Durham University |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | We take measurements on droplets drying in free air (levitated) using our instrumentation and regularly report our results to our partners at collaborative meetings. |
Collaborator Contribution | Our university collaborators take measurements of droplets drying on flat surfaces or of modelled droplets in spray-dryers and compare their results with ours at collaborative meetings. The industrial partners attend these meetings to discuss our results and comment on any issues in their processes which we could investigate in experimental measurements. Occasionally our industrial partners provide us with their own materials (e.g. milk powder, paint) for us to study droplet drying with in our instruments. |
Impact | This collaborative partnership has led to useful sharing of ideas and solving experimental problems. It also gives us direction about what interesting systems to try in our experiments so that we can better compare our results. |
Start Year | 2016 |
Description | Collaboration about droplet drying: comparison between spray dryers and droplets on surfaces |
Organisation | Inca Digital Printers Ltd |
Country | United Kingdom |
Sector | Private |
PI Contribution | We take measurements on droplets drying in free air (levitated) using our instrumentation and regularly report our results to our partners at collaborative meetings. |
Collaborator Contribution | Our university collaborators take measurements of droplets drying on flat surfaces or of modelled droplets in spray-dryers and compare their results with ours at collaborative meetings. The industrial partners attend these meetings to discuss our results and comment on any issues in their processes which we could investigate in experimental measurements. Occasionally our industrial partners provide us with their own materials (e.g. milk powder, paint) for us to study droplet drying with in our instruments. |
Impact | This collaborative partnership has led to useful sharing of ideas and solving experimental problems. It also gives us direction about what interesting systems to try in our experiments so that we can better compare our results. |
Start Year | 2016 |
Description | Collaboration about droplet drying: comparison between spray dryers and droplets on surfaces |
Organisation | Nestlé (Global) |
Department | Nestlé UK |
Country | United Kingdom |
Sector | Private |
PI Contribution | We take measurements on droplets drying in free air (levitated) using our instrumentation and regularly report our results to our partners at collaborative meetings. |
Collaborator Contribution | Our university collaborators take measurements of droplets drying on flat surfaces or of modelled droplets in spray-dryers and compare their results with ours at collaborative meetings. The industrial partners attend these meetings to discuss our results and comment on any issues in their processes which we could investigate in experimental measurements. Occasionally our industrial partners provide us with their own materials (e.g. milk powder, paint) for us to study droplet drying with in our instruments. |
Impact | This collaborative partnership has led to useful sharing of ideas and solving experimental problems. It also gives us direction about what interesting systems to try in our experiments so that we can better compare our results. |
Start Year | 2016 |
Description | Collaboration about droplet drying: comparison between spray dryers and droplets on surfaces |
Organisation | Sun Chemical Ltd |
Country | Canada |
Sector | Private |
PI Contribution | We take measurements on droplets drying in free air (levitated) using our instrumentation and regularly report our results to our partners at collaborative meetings. |
Collaborator Contribution | Our university collaborators take measurements of droplets drying on flat surfaces or of modelled droplets in spray-dryers and compare their results with ours at collaborative meetings. The industrial partners attend these meetings to discuss our results and comment on any issues in their processes which we could investigate in experimental measurements. Occasionally our industrial partners provide us with their own materials (e.g. milk powder, paint) for us to study droplet drying with in our instruments. |
Impact | This collaborative partnership has led to useful sharing of ideas and solving experimental problems. It also gives us direction about what interesting systems to try in our experiments so that we can better compare our results. |
Start Year | 2016 |
Description | Collaboration about droplet drying: comparison between spray dryers and droplets on surfaces |
Organisation | Syngenta International AG |
Country | Switzerland |
Sector | Private |
PI Contribution | We take measurements on droplets drying in free air (levitated) using our instrumentation and regularly report our results to our partners at collaborative meetings. |
Collaborator Contribution | Our university collaborators take measurements of droplets drying on flat surfaces or of modelled droplets in spray-dryers and compare their results with ours at collaborative meetings. The industrial partners attend these meetings to discuss our results and comment on any issues in their processes which we could investigate in experimental measurements. Occasionally our industrial partners provide us with their own materials (e.g. milk powder, paint) for us to study droplet drying with in our instruments. |
Impact | This collaborative partnership has led to useful sharing of ideas and solving experimental problems. It also gives us direction about what interesting systems to try in our experiments so that we can better compare our results. |
Start Year | 2016 |
Description | Collaboration about droplet drying: comparison between spray dryers and droplets on surfaces |
Organisation | University of Leeds |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | We take measurements on droplets drying in free air (levitated) using our instrumentation and regularly report our results to our partners at collaborative meetings. |
Collaborator Contribution | Our university collaborators take measurements of droplets drying on flat surfaces or of modelled droplets in spray-dryers and compare their results with ours at collaborative meetings. The industrial partners attend these meetings to discuss our results and comment on any issues in their processes which we could investigate in experimental measurements. Occasionally our industrial partners provide us with their own materials (e.g. milk powder, paint) for us to study droplet drying with in our instruments. |
Impact | This collaborative partnership has led to useful sharing of ideas and solving experimental problems. It also gives us direction about what interesting systems to try in our experiments so that we can better compare our results. |
Start Year | 2016 |
Description | Collaboration about inorganic droplet evaporation and crystallisation |
Organisation | University of Bristol |
Department | School of Physics |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | We provided experimental data on droplet evaporation using our instruments in the School of Chemistry. |
Collaborator Contribution | Our collaborators at the School of Physics used our data to fit to a model, to gain greater insights into the physics of crystallisation. |
Impact | We published a paper in a journal: Gregson, F. K. A.; Robinson, J. F.; Miles, R. E. H.; Royall, C. P.; Reid, J. P. Drying Kinetics of Salt Solution Droplets: Water Evaporation Rates and Crystallization. J. Phys. Chem. B 2018, 123, 266-276. DOI: 10.1021/acs.jpcb.8b09584 |
Start Year | 2017 |
Description | Collaboration about multi-component solvent evaporation |
Organisation | University of Alberta |
Department | Faculty of Engineering |
Country | Canada |
Sector | Academic/University |
PI Contribution | Experimental measurements on the evaporation of liquid aerosol droplets containing multiple volatile components. We collected all experimental data and shared it with our collaborators. |
Collaborator Contribution | Our partners in Canada performed modelling work, to model our data and hence build a greater understanding of the microphysics at play in evaporating droplets. |
Impact | Submission of two recent scientific publications. |
Start Year | 2017 |