DSA100
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Technical Note Technical note: Industry section: Cleaning, Coating, Printing, Surface Pretreatment Ming Jin and Dr. Thomas Willers DSA100L with Liquid Needle Dosing Unit – DS3252 Method: Keywords: wetting, adhesion, quality control, contact angle, surface treatment, cleaning Inline process control of wettability by means of contact angle measurement on moving surfaces The fast Liquid Needle dosing technique and a flexible software interface pave the way for integrated quality testing Contact angle measurement has completed the step from the test laboratory into the production hall with regard to quality assurance for the cleaning and pretreatment of surfaces. This has been made possible thanks to the development of fast and mobile measuring technologies. We go even further with this feasibility study and show a way for the potential use of contact angle measurements as a test method for uninterrupted inline process controls. Two recent innovations from KRÜSS open up this perspective: the extremely fast Liquid Needle technique that enables contact angle measurements on moving samples and the ADVANCE API software interface with which the integration of fully automatic analyses is possible in any complex information systems. Background Materials are subjected to surface treatment in many production processes, in order to prepare these for further processing steps. Typical examples here include the cleaning of surfaces before bonding or plasma treatment of a polymer in order to activate it for subsequent coating and thus achieve the best possible wettability and adhesion. As wetting is reflected directly by the contact angle, measuring the contact angle is an excellent way of testing the efficacy of such pretreatment methods [1]. Photo: Plasmatreat Pretreatment is often carried out on samples that are continuously moving. Until now the inline control of such dynamic processes was not possible for the following two reasons: KRÜSS GmbH | Borsteler Chaussee 85 | 22453 Hamburg | Germany | www.kruss.de

1. Deposition of a drop with a classic needle dosing system is too slow for moving samples; the drop smears on the sample. Attempts to shoot the drops onto the sample fail due to excessive impact speeds that lead to falsified contact angles and larger error bars. 2. There was no technology for the integration of contact angle measurements in a comprehensive information system, nor the automatic synchronization of results with sample information or even for establishing feedbacks with process parameters such as cleaning and activation time. KRÜSS has developed solutions for both impediments....

ADVANCE API, so that countermeasures can be taken in good time thus preventing greater loss of production. KRÜSS Application Report AR272 M. Jin, R. Sanedrin, D. Frese, C. Scheithauer and T. Willers, “Replacing the solid needle by a liquid one when measuring static and advancing contact angles”, Colloid Polym. Sci. 294(4), 657-665, DOI 10.1007/s00396-015-3823-1 (2016). You will find many other interesting Application Reports and Technical Notes at https://www.kruss.de/services/educationtheory/literature/application-reports/ Fig. 3: The contact angle measured on each 50 drops on the moving...