I have known Lars Heim for more than 30 years. In the mid-1990s, he learned atomic force microscopy from us. His project was about the formation of planets through the aggregation of cosmic dust. He further developed the process of sticking colloidal particles to cantilevers. During his time in my working group, he made a variety of contributions in several areas. He was the first to measure rolling friction between particles using a colloidal probe.
I have known Lars Heim for many years, from our early days working together
on investigations into interparticle force measurements and the further development of the colloidal probe technique in Hans-Jürgen Butt’s group. His solid scientific background, his precise experimental approach and his innovative problem-solving have always impressed me. I can warmly recommend Lars Heim as a contact person to anyone who is tackling current problems in the area of colloidal probes.
There was previously a link to NanoAndMore here. It was only through contact from sQUBE that NanoAndMore first became aware of Colloidal Probes and expanded the market in cooperation with us. An exclusive supply relationship with sQube GbR existed until 2023. This was terminated by NanoAndMore without further explanation. Since then, NanoAndMore has not purchased any further products from us. We would like to point out that there is also no connection between us and the website sqube.com. We are currently considering legal action in this matter.
If you would like to continue to rely on the usual quality and expertise for your Colloidal Probes, please order directly from us or contact us.
In addition to the “standard products”, we offer you extensive support in a wide range of questions relating to your investigations. This ranges from special treatments, sample preparations, individual geometric arrangements to the provision of individually desired particles and reference surfaces.
We welcome special positioning and arrangements of objects in the micrometer range, both on or at cantilevers and on reference structures and surfaces. In principle, we are keen to discuss any of your approaches in order to develop a solution together.
If you have special requirements (chemical modifications/pre-treatment) for the particles, we will be happy to advise you in detail. There are various methods available for determining the geometric parameters of the fixed particles:
To quantify the forces between the sample and the surface, the individual determination of the spring constant of cantilevers is of fundamental importance. This value is used to calculate the surface energy, the elastic modulus and the adhesion force.
On request, the cantilevers can be individually calibrated at sQUBE.
We also calibrate the torsional spring constant of cantilevers to perform quantitative friction measurements.
High-resolution images
The atomic force microscopy method enables the visual representation of surfaces with a resolution down to the atomic level. The three-dimensional information obtained in this way can be evaluated in a variety of ways.
Force measurements
Surface properties such as adhesion or zeta potential (surface charge) can also be investigated using force measurements. Information is obtained based on the forces required to detach a measuring tip from the surface or to approach it. External parameters (temperature, ambient atmosphere, etc.) can be varied in a defined manner.
Force measurements between particles in the micrometer range
Forces between individual particles or particles and surfaces can also be measured. This allows the influence of surface modifications on process sequences to be directly analyzed, for example adhesion properties on the walls of dispersers (pharmaceutical applications) or surface modifications to facilitate cleaning processes (lotus effect).
This optical method is based on the confocal multi-pinhole technique and enables the contactless 3D characterization of complex surfaces with high vertical (up to 2 nm) and lateral (up to 300 nm) resolution. In addition to images at different magnifications in incident and transmitted light, laser scanning methods can also be used to image 3D profiles.
The contact angle between a liquid and a surface is a measure of the wettability of the surface. It thus quantifies the energetic interaction between them. It is usually determined optically using the sessile drop method. The contact angle depends on the chemical composition of the surface (the outer 0.5 to 1 nm of the boundary phase are crucial here) and on its topography. The contact angle is therefore a measurement that is sensitive to very small changes on the surface. By measuring the contact angles of test liquids with different polarities, the surface energy of the solid can be determined taking into account its polar and disperse components.
Do you need information about equipment or measurement techniques in the field of surface analysis:
What techniques are available, what conclusions can be drawn, what information is relevant to you?
sQUBE is at your disposal with competent expertise.
sQUBE offers seminars and in-house training courses on surface analysis and instrumentation, tailored to your needs.
