Theta

Applications

Theta is an optical tensiometer for highly accurate and easy measurements of:

• static contact angle
• dynamic contact angle
• surface free energy
• surface tension
• interfacial tension
• interfacial rheology
• wettability
• absorption
• adsorption
• spreading
• cleanliness
• surface heterogeneity

Measuring with Theta

Theta can measure:

• static contact angle
• dynamic contact angle
• surface free energy
• surface tension
• interfacial tension
• interfacial rheology (with pulsating drop module)

The available drop profiles are: sessile drop, pendant drop, receding contact angle, tilting drop, advancing contact angle, captive bubble, meniscus and reverse pendant drop.

As an optical method, the measurement precision of optical tensiometers depends on the quality of the pictures and the analysis software. Attension optical tensiometers utilize a unique monochromatic cold led light source as well as a smooth lighting integrating sphere to minimize undesirable sample evaporation. Image quality is guaranteed by a state-of-the-art high-resolution digital camera and a high speed data transfer between the computer and the instrument.

The optical tensiometer software, OneAttension, enables superior analysis of drop shapes, using for instance the Young-Laplace equation which is able to fit the entire drop profile and is the reference method, first brought to optical tensiometers by Attension. It complies with the promise of performance and simplicity:

• Fully automatic measurements avoids user dependant variation and saves time.
• Select readymade experiment recipes or create custom programs for quick and repeatable operations.
• Automatic base line detection and drop shape fitting
• Contact angle on curved surfaces (circular or near-circular)
• Flexible and programmable frame per second rate recorded by the camera

OneAttension is an all-inclusive software enabling immediate access to all measurement capabilities with no need to purchase and install separate software modules. It features an intuitive user interface, live analysis, configurable user groups and accounts and a preset liquid database. Any datapoints or groups of datapoints can be selected, transformed, plotted and analyzed. Data can easily be exported. In-depth analysis is now just a matter of seconds.

Precision, robustness and intuitive user experience are built-in. All you need to do is select the level of automation and advanced functionalities you need. Theta quality camera and optics are enhanced by a x6.5 zoom lens enabling characterization of very small drops. Camera frame rates vary from 60 up to 1550 fps. The open design and large frame are appropriate for large samples. With motorized sample stage, motorized vertical movement and a dispenser Theta can function fully automated, placing drops in a predetermined locations on the substrate and measuring the contact angles.

Technical specifications

Drop Profile Fitting Method

• Young-Laplace
• Bashforth-Adams
• Circular
• Polynomial

Surface Free Energy Calculation Methods

• Zisman Plot
• OWRK
• Simple Fowkes
• Extended Fowkes
• van Oss Acid-Base
• Wu
• Equation of State
• Schultz 1
• Schultz 2

Recommended System Requirements

2GHz processor, 1GB MB RAM, 40 GB hard disk drive (20GB free), 1024x768 resolution, 1 USB port, 1 Firewire port or 1 PCI slot


Operating System Requirements

Windows 7 (32 or 64 bit), Windows Vista (32 bit), Windows XP SP3 (32 bit).

More information is available from the product catalogue. Accessories and modules can be found here.