Skip to main content
European Commission logo
English English
CORDIS - EU research results
CORDIS
CORDIS Web 30th anniversary CORDIS Web 30th anniversary
Content archived on 2024-05-28

In-line characterisation of nanoparticles using a combination of analytical techniques in real time

Periodic Report Summary - IN-SIGHT (In-line characterisation of nanoparticles using a combination of analytical techniques in real time)

Project context and objectives:

The field of nanotechnology is currently experiencing a stage of exponential growth. Nanoparticles (NP) enter our daily lives through a range of consumer goods, and currently over 1000 consumer products contain nanoparticles, including cosmetics, sunscreens, paints and surface coatings. It is predicted that EUR 1 trillion nanotechnology-enabled products will be on the market by 2015. Nanotechnology development is attenuated due to the difficulty to measure critical features such as NP size, number, shape and composition. Indeed, there are considerable number of characterisation methods for NPs based on microscopy (imaging) or spectroscopy (analysis); however, all of the techniques used require laboratory-based equipment and are currently not suitable for in-line NP monitoring. At present, the nanomaterials (NM) manufacturers use offline techniques to determine the characteristics of the NP containing formulation or product. This is an indirect and costly procedure; the analyses are often time consuming (laborious) and cannot be used for trouble-shooting or in-line quality control. Consequently, it is more difficult for NP manufacturers to be certain that the production of NPs is accurately controlled. Therefore, one essential prerequisite for the development, manufacturing and commercialisation of NMs is the availability of techniques and tools for real time characterisation on the nanoscale level. Thus, the project aims to develop new and improved tools for real-time monitoring of the following NP properties:

- NP shape and mobility;
- NP counting and sizing;
- NP composition and structure.

The project will develop the following three real time in-line tools for NP characterisation:

1. Visualisation of particles in the reactor by optical techniques; this will be a combination of in-situ particle viewer (ISPV) (optical microscopy) with NTA (NP tracking analysis; laser light scattering microscopy) to retrieve information on number of particles, particle size and -distribution.
2. Enhancement of ultrasonic particle measurements (UPM) (ultrasonic spectroscopy); nowadays, used for real time micrometer-sized particle analysis, for NP number and size analysis.
3. Combination of laser-induced breakdown spectroscopy (LIBS) with Raman - a new combination of technologies available today for real-time measurement of atomic and molecular analysis.

In-Sight implements three defined locations for analysis in sense of timing. Two locations in real time:

1. in-line: the analysis is performed in the reactor without influencing the process;
2. on-line: a sample is taken for a short time from the reactor and analysed in a bypass loop.

After analysis the sample is returned to the reactor. The third one is off-line which means that a sample is taken from the reactor and analysed in the lab. The validation and calibration of new tools will be performed off-line, the proof-of-concept of real time measurement will be on-line.

Project results:

NP synthesis and analysis off line:
A framework of different particle system was established on which the different instrument developments would be based. These particle systems are thoroughly characterised and a comprehensive catalogue was established. The concerning particles are available for the partners of the consortium for the further work. In the first 18 months, the consortium partners have performed at their own laboratories two series of Round Robin tests, off-line characterisation of NPs and NMs. It has been shown that sample handling and measurement protocol are of extreme importance and require proper communication from producer to user.

NP shape and mobility:
An optical microscope for measuring particles smaller than 1.0 micron was optimised by partner Perdix. Using a high-end 100X oil-immersion objective lens, a micro-fluidic flow-cell and a very high power blue light-emitting diode (LED), promising results have been achieved. Thus, it has been shown that particles with a size of around 350 nm can be detected and measured in a reasonable flow. Another technology to determine the particle size and concentration is based on laser light scattering microscopy. Currently, this technology is used for off-line NP measurements. Partner Nanosight has further developed this technology during the In-Sight project to allow on-line measurements of NP under flow conditions (NP tracking analysis, NTA). An automated dilutor and computer controlled liquid handling system have been integrated with the NP tracking instrument. With automated procedures, samples have been successfully diluted 125 000 times, analysed and cleaned from the chamber with a total changeover time of around 7 minutes.

NP composition and structure:
Partner TNO developed a novel Raman-LIBS setup that allows NP detection in liquids. Their results show that a large variety of NP can be detected, with dimensions ranging from 5 nm to a few micrometres, covering a wide range of concentrations within a few seconds. TNO has been able to determine their chemical composition resulting in a possibility to determine doping concentration and core-shell ratio. It was also shown that for some of the particles their particle size could be deduced from the spectra obtained.

NP counting and sizing using ultrasound:
Partner SON has demonstrated the feasibility of manufacturing an acoustic cell for use in attenuation and speed of sound measurements for particle dispersions relevant to the consortium. It was shown that they are able to measure the size distribution of particles in a dispersion of sub-micron size silica particles in water. Next step will be to optimise the frequency of the transducer to yield successful NP measurements. In order to interpret the future results of the measurements using the acoustic cell, substantial efforts has been dedicated to modelling and inversion and their comparison to NP measurements using other techniques. This activity led to development of improved measurement algorithm to unravel NP size distribution following attenuation and speed of sound measurements of NP.

Data analysis:
In order to combine the measurements of all instruments to obtain a more accurate estimate of the particle size / shape distribution, a framework has been developed for data fusion. For each instrument, a model will be derived for the response a certain particle ensemble. Using the models as observers, an optimal estimator will be derived. The results of the estimator will be feedback to the instruments, to provide a more reliable and accurate estimate of properties the instrument requires for the interpretation of the measurement signals. By iterating, it is expected to obtain an even more accurate final result.

Potential impact:

In-Sight will result in analytical tools that do not exist at this moment for NP characterisation and that will be upgraded for NP characterisation in-line and on-line during nanomaterial production processes. The proposed real-time monitoring will improve process reliability and reproducibility, thus improved yield and quality. Furthermore, it will enable quality by design throughout the development of new products resulting in a reduction of the development time and easy scale-up (from the lab to manufacturing) improved process reliability and reproducibility thus improved yield and quality. This due to the fact that the novel tools will enable scientists, formulators and engineers to monitor and control real-time changes in NP characteristics (e.g. NP agglomeration) thus optimising, troubleshooting and calibrating the process. This will further improve the product characteristics and lower their costs.

Socioeconomic impact of expected results:
Nanotechnology is an enabling technology with far-reaching effects. It provides a new competitive edge to the European industry and to the European economy as a whole. Market analysts foresee a world market for nanotechnologies of EUR 750 - 2000 billion by 2015, and estimate that 10 million nano-related jobs will be created by 2014, i.e. 10 % of all manufacturing jobs world-wide. The results of the project can be commercialised within the nanomaterial industry and beyond. The equipment manufacturers will be able to enter new markets due to their sensitive, accurate and reproducible NP monitoring tools. This will further increase their turnover and employment.

The NPs, NMs and equipment manufacturers will benefit from the outcome of In-Sight since it will stimulate, and create new markets for their products. This will result in an increased turnover and employment for the tool- and equipment manufacturers.