Do you need to characterize or evaluate surface cleanliness?

Surfaces surround us and are found everywhere. We are on them, live in them and use them. In many situations their cleanliness is of interest, of importance and in some cases their cleanliness can even be critical. What “clean” means is of course a matter of definition, ranging from macroscale cleanliness all the way down to the nanoscale and everything in between.

The first category of surfaces that may come to mind when thinking about cleanliness, are the surfaces in our homes and objects in our immediate vicinity that we use in our everyday life – kitchens, bathrooms, our clothes and perhaps our means of transportation such as our car. But we also expect that public spaces should be hygienic – restaurants, public transportation and hospitals. The latter is one of those areas where cleanliness at the nanoscale could be critical. For example, the cleanliness of surgical tools and other surfaces in hospitals are key for successful surgery and to prevent spreading of disease. Even farther away from us we have for example, production and process industries, such as for food, pharmaceuticals or other sensitive substances where switching from the manufacturing of one component to the other may require surface sanitation in between. Or in the electronics and optics industry and the manufacturing of electrical circuits or coatings, where the slightest dust molecule may be disastrous. Other structures, such as oil pipelines and heat exchangers in power plants, are exposed to pollution and the accumulation of unwanted material over time, such as deposit formation, build-up of scale, biofilm formation and fouling, which may deter function. 

Real-time characterization and assessment of surface cleanliness

QSense® QCM-D can measure and quantify deposits, scale build-up, and biofilm formation as well as removal of the same, in real time and quantitatively at the nanoscale. You can also characterize cleanliness before, after and during as a function of context in cases where it is important to optimize conditions to minimize or prevent build-up of unwanted material. Examples range from assessing cleanliness of kitchenware, to characterizing biofilm formation and measuring asphaltene adsorption from crude oil fouling in pipelines, which can help develop methods or additives to eliminate them.

Fast evaluation of surface cleanliness by contact angle measurements

The efficiency of cleaning and detergent formulations can be evaluated by contact angle measurement.

Surface free energies of clean and treated surfaces are directly correlated to the cleanliness and surface composition. Contact angle is one of the most sensitive of all surface analytical techniques since even the top nanometer of the surface influences wetting behavior. As a simple and fast measuring technique, contact angle is commonly utilized to follow the cleaning process and the effectiveness of cleaning solutions. Contact angle measurements are therefore a highly suitable quality control method in areas where cleanliness control is crucial. Contact angle measurements by automated Theta give a user-independent and quick method for cleanliness evaluation.

Cleanliness of silicon wafers and circuit boards is an important factor in ensuring the optimized functionality of the final product. The cleanliness of glass surfaces has a direct effect on the quality of any subsequent processing steps such as inkjet printing of bottles or using adhesives for label application. Measuring glass contamination helps in reducing waste and ensuring efficient production.