Pursuant to the modular design of the OCA series, DataPhysics Instruments provides a wide range of accessories that allow to find the right configuration for your specific interfacial challenge. This extensive range of optional modules, components and accessories includes various dosing systems, temperature and environment control systems, sample positioning and holding systems, and further special accessories.
In order to dose drops precisely and reproducibly different tubeless direct dosing systems are available. They utilise glass or disposable syringes which provides for short preparation times and minimal cleaning efforts. This applies to both manually positioned single syringe modules and to multi-dosing systems with up to four electronically selectable and positioned syringes. Especially small droplets that are required to analyse micro-structured samples can be created with special nanolitre or picolitre dosing systems.
The direct dosing systems are attachments that are mounted directly on the illumination housing of all OCA systems. The direct dosing systems allow either for a manual positioning of one or two electronic syringe modules or an automatic electronical positioning of between one and four electronic syringe modules.
The single direct dosing system SD-DM can be used to manually position one electronic syringe module. It is the ideal entry level solution for measuring surface and interfacial tension with the pendent drop method. The SD-DM consists of one syringe module carrier with fine adjustment screws for the axial and horizontal needle positioning and a connection cable
The double direct dosing system DD-DM can dose two different liquids on a substrate for the determination of the surface energy. The DD-DM consists of two syringe module carriers with fine adjustment screws for the axial and horizontal needle positioning and two connection cables
Single direct dosing system SD-DM and double direct dosing system DD-DM
The electronic multiple direct dosing system DDE/x offers a precise electronic syringe selection and positioning. The DDE/x can be controlled with the TP 50 control panel and via the SCA software. Due to the ability to electronically select and position up to four different liquids above a sample the determination of the surface energy of solids can be easily automated.
The DDE/x features the following technical data:
Depending on the version up to four electronic syringe modules can be used:
Threefold and fourfold electronic direct dosing systems DDE/3 and DDE/4
Single and double electronic direct dosing systems DDE/1 and DDE/2
The electronic syringe modules ESr-N which are usable with all dosing systems work with glass or disposable syringes and dose down to typically 1 μl small drops. Due to the electronic piston drive, the ESr-N can automatically dose precise liquid volumes. Moreover, the ESr-N is already prepared for nanolitre dosing.
The ESr-N features the following technical data:
The achievable dosing rates depend on the utilised syringe. Some typical dosing rates are:
Electronic syringe module ESr-N
An essential requirement for an accurate contact angle measurement is that the drop does not touch or wet beyond the edge of the test surface. This poses the challenge to dose especially small drops when analysing micro-structured samples like printed circuit boards, small medical products, lithographic structures, precision mechanics and assembly components, wires and single fibres. That challenge is met by innovative special dosing systems from DataPhysics Instruments.
The microlitre-sized drops dosed with a standard dosing system have base diameters in the millimetre range, depending on the contact angle. This equals about the size of a pin head.
With a nanolitre dosing system from DataPhysics Instruments droplets down to volumes a hundred times smaller, typically 10 nanolitres, can be dosed. These drops fit, for example, into the screw threads of a dental implant whose surface is to be investigated.
The mesh structure of a coronary stent presents an even smaller test area. Its surface properties have to be optimised in order to prevent the vessel from being blocked by tissue regeneration. In this case the picolitre dosing system PDDS is utilised to create drops down to 30 picolitres.
Base diameter diagram
Nanolitre drop between the screw threads of a dental implant
The standard electronic syringe module ESr-N can easily be upgraded to a nanolitre dosing system by the addition of a nanolitre dosing valve. Thus contact angle measurements on micro-structured samples become possible with little effort.
With an air-filled syringe in the ESr-N module, the liquid in the dosing tube is pushed against a magnetic dosing valve. The valve is triggered by the SCA software. This setup allows to reproducibly dose up to 250 droplets per second down to 10 nl.
Dosing picolitre droplets on solid substrates carries optical contact angle measurement to the extremes. DataPhysics Instruments’ newly developed picolitre dosing system PDDS enables to reproducibly dose droplets of down to 30 picolitres. Hence, depending on the contact angle, drop base diameters considerably below 100 micrometres are achieved. Even with this high precision the picolitre dosing system PDDS is capable of dosing up to 1000 droplets per second.
What makes working with the PDDS particularly easy are the disposable cartridges used as test liquid containers. Their volume is only 100 microlitres being economic regarding both material cost and waste. Moreover, time-consuming cleaning procedures are not necessary and cross-contamination is impossible. This makes working with even the most challenging formulated liquids, including inks or surfactant solutions, routine.
Dosing systems brochurefile_download
Picolitre dosing system PDDS
Nanolitre dosing system
The Liquid Jet systems are based on the same dosing principle as the nanolitre dosing system. By pushing the liquid against a magnetic valve using air pressure, a liquid jet can be generated upon opening the valve. Due to their small size several valves can be positioned side by side. Hence, multiple drops can be dosed simultaneously and analysed within the same field of view.
By dosing and analysing multiple drops at the same time the process of determining the surface energy of solids can be accelerated dramatically and a one-click surface energy determination can be realised.
Due to their design the Liquid Jet systems are not restricted to the typical test liquids diiodomethane and water. Hence, the surface energy determination can even be done on samples that react with water or diiodomethane. Furthermore a Liquid Jet system can be used for measuring the surface tension using the pendant drop method with just a few simple modifying touches, without the need of buying any additional accessories.
The Double Liquid Jet system DLJ features two Liquid Jets and is the basic solution for determining the surface energy of solids at one-click. Additional Liquid Jet systems with more than two jets are available, allowing an estimation of the accuracy of the determined surface energy result.
In our application note you will learn how the Double Liquid Jet system DLJ can be used to perform a one-click surface energy determination.
To the application notenavigate_next
Two simultaneously dosed and analysed drops using the Double Liquid Jet system DLJ
The OCA product series comprises a wide range of different dosing syringes and suitable needles. Inside the electronic syringe module ESr-N gas tight glass syringes can be used as well as cost efficient disposable syringes. In the following is a selection of the most important syringes:
With different needle types and sizes intended for either sessile or pendant drop or captive bubble measurements the right tool for every task is always at hand. For use with glass syringes needles made of stainless steel and made of stainless steel with PTFE coating are available. For use with the disposable syringes disposable needles are also available. The needles are arranged in groups according to the standard application of the needle:
Top to bottom: DS 100/GT, DS 500/GT, DS 1000/GT, DS-D 1000SF and DS-D 3000 LL
Needles for sessile and pendant drop method in several disposable and non disposable variants
Upwards bent dosing needles SNC xx in various diameters
For a proper pendant drop evaluation and an easy placement of drops for the sessile drop method a wetting of the outer needle surface should be avoided. The hydrophobisation kit contains a specially formulated coating liquid that can be used to treat dosing needles before use. After treatment the needle surface is highly hydrophobic and unwanted wetting is far less likely.
Hydrophobisation kit for dosing needles with needle before and after treatment
The modular approach to the design of the OCA series and the availability of a wide range of accessories facilitate optical contact angle measurements and drop contour analysis under various environmental conditions. Temperature, humidity and pressure can be set and precisely controlled. This enables the recreation of the most diverse application scenarios and the analysis of samples under real life conditions.
With the syringe heating device SHD a syringe inside the electronic syringe module ESr-N can be heated using a liquid circulator bath. Hence, depending on the used circulator syringes and the contained liquids can be temperature controlled from -10 … 90 °C.
The SHD consists of the following parts:
Syringe heating device SHD
With different environmental chambers measuring temperatures from -30 °C to 700 °C can be reached. All temperature chambers feature three windows made of special optical glass for observation and measurements with the OCA models as well as a set of two Pt 100 temperature sensors and an inert gas inlet. Also included with every temperature chamber are special cover plates in order to optimization the needle entry gap for varying samples.
The liquid temperature control unit TFC 100Pro is used in conjunction with a liquid circulator bath. The TFC 100Pro features:
The Peltier temperature control unit TPC 160 utilises an electric Peltier system for temperature control. The TPC 160 requires a liquid counter cooling and features:
The electrical temperature control units TEC 400 and TEC 700 use electrical resistance heating of the chamber floor and lid. The TEC 400 and TEC 700 feature:
Electrical temperature control unit TEC 700 with temperature controller for up to 700 °C
liquid temperature control unit TFC 100Pro for temperatures of -10 … 100 °C
Peltier temperature control unit TPC 160 with temperature controller for -30 … 160 °C
Dedicated to investigating the properties of metals, polymers or hot melts in their liquid state are the electrical needle heating devices NHD 400 and NHD 700. This special piece of development enables the dosing of molten solids at temperatures up to 400 °C or 700 °C, respectively. Hence the surface tension of, for example, molten aluminium can be determined.
The NHD 400 and NHD 700 feature:
Electrical needle heating device NHD 700
Inside the high temperature furnace HTV 1800 from DataPhysics Instruments contact angle measurements at up to 1800 °C and under vacuum down to 10-5 mbar, or inert gas atmosphere, are possible.
The high temperature furnace HTV 1800 is available as part of an OCA 25 special model.
OCA 25-HTV 1800 brochurefile_download
High temperature furnace of OCA 25-HTV 1800
OCA 25-HTV 1800 with optional trolley cart
Inside the high pressure chamber PMC 750 from DataPhysics Instruments interfacial tensions and contact angles can be measured at pressures of up to 750 bar and under high temperature conditions of up to 200 °C.
The high pressure chamber PMC 750 is available as part of an OCA 25 special model.
OCA 25-PMC 750 brochurefile_download
High pressure cell of OCA 25-PMC 750
OCA 25-PMC 750
The humidity generators of the HGC series allow for a reliable control of the relative humidity, in the range of 5 % to 90 %, inside environmental chambers from DataPhysics Instruments or other suppliers. Due to the integrated touch screen the system can be operated without additional software and is directly ready for use. Of course, the software of the DataPhysics Instruments measuring instruments includes, integrated, HGC humidity control.
To the HGC series
For measuring dynamic contact angles according to the tilting method, the solid sample has to be tilted from its horizontal position. Measuring the dynamic contact angle on a tilted sample directly yields the advancing, receding and rolling angle as well as the contact angle hysteresis of sessile drops.
The manual tilting base assembly TBA 60M is placed on top of the sample stage of an OCA model. Using the manual hand wheel the top of the tilting base assembly can be tilted from 0° to 70°.
The electronic tilting base unit TBU 100 fully automatically tilts the entire OCA device in a range of -5° to +95° including attachments like dosing systems and environmental chambers. By tilting the entire system the position of the sessile drop within the optical axis does not change and analysing dynamic contact angles becomes even easier.
The TBU 100 can be controlled via the TP 50 control panel and the SCA software.
Electronic tilting base unit TBU 100 with OCA 50
Application video: Water Roll-off
Manual tilting base assembly TBA 60M
The electronic turn tables with vacuum fixation ETT/VAC facilitate the mapping of silicon wafers. They allow to access any position for contact angle measurements, even on 12″ wafers. The ETT/VAC features a connection socket for a vacuum pump and can be equipped with different sized top plates:
Electronic turn table with vacuum fixation ETT/VAC
Various different holders allow for a secure fixation and easy positioning of films, papers and even single fibres.
The single fibre holder FHO 40plus can securely span fibres of any thickness and with a length ranging from 25 mm to 70 mm with adjustable tension. Additionally the inclination and position of the fibre can be adjusted with manual axes.
The thin film sample holder FSH 30 is made of Delrin and is especially designed for thin films and foils. It consists of:
The film and paper holders FSC 80 and FSC 150 can be used to span thicker films or papers with adjustable tension. The maximum usable sample sizes are (LxWxH):
Single fibre holder FHO 40plus
Holders for thin films FSH 30 and for films and paper FSC 80
The standard sample table of any OCA model can be replaced with optional specialised sample tables for easier handling of various sample types.
The sample table STC 100 features holding clamps that reliably and easily fix flat samples like glass slides. The use of the STC 100 is recommended when working with the TBU 100.
The suction plate SP 100 is designed to hold especially thin and flexible samples flat against the table using an adjustable suction area. The SP 100 comes with a connection socket for a vacuum pump.
Films or fabric can be spanned over the curved sample table FHM 100 and to which they are fixed with lateral magnetic bars.
Suction plate SP 100
Sample table with holding clamps STC 100
Curved sample table with magnetic bars FHM 100
For the lamella method DataPhysics Instruments designed special sample vessels and test pieces. The test pieces TPL feature a connector for attachment to a glass syringe of the type DS xx/GT and a sphere of different diameters at the other end. In combination with the special sample vessels SVL with different diameters a lamella of for example molten solids can be pulled out of the vessel and analysed with the SCA 23 software module. Available test pieces and sample vessels:
TPL and SVL
The interfacial tension between two liquids according to the pendant drop method and the contact angle of a liquid drop or gas bubble according to the captive bubble method can be measured using glass cells made of special optical glass. The glass cells are usable at up to 70 °C or in a high temperature version at up to 350 °C. The glass cells are available in the following sizes (LxWxH):
Pendant Drop in GC 10
The sample holder SHC 20 for captive bubble measurements fits into a glass cell GC 50 and allows for a flat attachment of samples during captive bubble experiments. Together with the glass cell and a specially bent needle SNC xx a gas bubble can be dosed beneath the sample holder.
Captive bubble equipment with SHC 20
With the contact lens supports CL 20 and SCL 21 contact lenses can be held inside a glass cell for captive bubble experiments. The SCL 21 features adjustable inlet pieces with three different radii of curvature to attach especially soft contact lenses without deformation of the shape.
Contact lens support CL 20
Holder for soft contact lenses SCL 21
In close cooperation with customers, research institutes, and universities DataPhysics Instruments developed a wide range of application specific accessories to complement the OCA series.
DataPhysics Instruments provides several sets of optical standards for the validation/verification of the OCA performance. Each glass slide features a standard sessile, pendant drop or lamella contour for image capture and subsequent analysis.
The comparison of the measured contact angle, surface or interfacial tension with the one stated on the slide is a crucial factor in the evaluation of instrument performance and reliability. All slides are manufactured with the highest precision, as per ISO 9001, in a controlled photolithographic process to serve as reliable references for the precision of measured data.
The OCAS basic set consists of two standard sessile drop shapes and one standard pendant drop shape. Various other shapes are available as well.
OCAS basic set
The Topview Video System TVS opens up a completely new approach to contact angle measurement. With this system deposited drops are monitored and evaluated in topview which allows to investigate previously inaccessible sample spots, for example, at the bottom of indents of ready-made components or on assembled printed circuit boards. Moreover, the TVS enables the determination of surface homogeneity and surface isotropy.
The Topview Video System TVS comprises an electronic syringe module which is used to dose a liquid drop with a well-defined volume via a bent needle. The drop is observed from the top by a camera with high resolution optics. If desired the already existing optics and camera of the OCA model can be mounted on the TVS holding system. For sample illumination two different systems are available which ensure an optimal contrast of the drop image depending on the reflectivity of the surface:
Subsequent image processing of such contrast optimised pictures with the SCA 27 software module is of course easily feasible.
Topview measurement with the TVS-C on a printed circuit board
TVS-R and TVS-C
The TP 50 control panel with touch screen and precision control wheel establishes a comfortable and intuitive control of all electrical components of the OCA series, ranging from the electrically driven sample table over the electronic dosing systems up to any additionally attached modules such as a humidity generator. The precision control wheel allows to make settings exceptionally fast and still with the highest accuracy.
(The TP 50 control panel is included with an OCA 50 or an OCA 200)
TP 50 control panel with touch screen and precision control wheel
All OCA models can be equipped with the top view observation video system TV-VS. The TV-VS is mounted above the OCA main camera and provides an alternative view of the positioning of the dispensed drops on the surface. Hence, a solid documentation of the sample mapping is guaranteed. The TV-VS features an USB camera with high performance 6-fold zoom lens and adjustable observation angle.
The electro wetting platform EWP 100 is designed to investigate the influence of an electric field on the wetting and adsorption behaviour of modern, engineered materials. The EWP 100 facilitates the analysis of sessile and pendant drops in a defined electric field.
It features electrodes integrated into the top and bottom plate and connectors to a standard external lab voltage supply. With different spacer elements the distance between the electrodes can be adjusted.
By analysing the shape of oscillating drops, additional parameter like the surface or interfacial compression modulus, surface or interfacial dilatation elasticity and the surface or interfacial dilatation viscosity can be determined. For the analysis of oscillating pendant drops the SCA 26 software module is required. DataPhysics Instruments offers two systems to generate oscillating pendant drops.
The electronic syringe module ESr-O is designed for creating sinusoidal oscillating and relaxing pendant drops. The ESr-O is placed inside a syringe module carrier of a manual or electronic direct dosing system. The ESr-O features the following technical specifications:
The oscillating drop generator ODG 20 utilises a piezoelectric actuator to create an oscillating pendant drop. Due to the high performance actuator the ODG 20 is able to create higher oscillation frequencies and can even oscillate the drop shape without changing the drop volume. The ODG 20 features the following technical specifications:
Oscillating drop generator ODG 20
Electronic syringe module for oscillation ESr-O
The liquid injection system LIA-MD allows the addition of a second liquid into an existing pendant drop. Via a second electronic syringe module the second liquid is being injected directly into the pendant drop. By injecting surface-active or chemically reactive phases the relaxation of the pendant drop back into its equilibrium state is indicative of the reactivity of the liquids under study. The LIA-MD consists of:
Liquid injection system LIA-MD
OCA brochurefile_download OCA 25-HTV 1800 brochurefile_download OCA 25-PMC 750 brochurefile_download Dosing systems brochurefile_download
App. note 1-Click SEfile_download