HARKE SFT-A1 Advanced Surface Tensiometer

Overview

The HARKE SFT-A1 Advanced Surface Tensiometer is a dual-method, benchtop instrument engineered for high-reproducibility measurement of surface and interfacial tension using the standardized Du Noüy ring and Wilhelmy plate techniques. Based on electromagnetic balance force transduction—eliminating mechanical drift associated with torsion-wire systems—the SFT-A1 delivers stable, traceable measurements across dynamic and equilibrium conditions. Its modular architecture supports both static and time-resolved tension profiling, enabling characterization of surfactant adsorption kinetics, interfacial relaxation, and critical micelle concentration (CMC) determination. Designed for routine QC laboratories and advanced research environments, the instrument complies with internationally recognized test standards including ISO 1409 (plastics), ASTM D971 (petroleum products), and DIN 53914 (coatings and inks), ensuring data interoperability with peer-reviewed literature and global instrumentation benchmarks.

Key Features

• Electromagnetic balance sensor with 0–120 g full-scale capacity, delivering ±0.01 mN/m display resolution and ±0.1 mN/m measurement accuracy per ISO 1409 calibration protocols
• Dual-method capability: fully automated Wilhelmy plate (A3/A4 methods) and Du Noüy ring (A5 method) testing per HARKE’s proprietary SFT-A1 software suite
• Motorized vertical stage with programmable speed (0–10 mm/sec) and sub-millimeter positioning precision (±0.1 mm) for controlled immersion/emersion cycles
• Integrated ambient-temperature operation with optional thermal modules: Peltier-based heating (up to 80 °C) or external circulating bath interface (±0.1 °C stability)
• Embedded industrial-grade controller replacing conventional PC dependency—enabling standalone operation with identical functionality, data integrity, and real-time visualization
• Dual-display mode: simultaneous numeric surface tension value and real-time force vs. position curve, supporting manual validation against Young–Laplace and Harkins–Jordan correction equations
• Multi-functional platform: integrated precision microbalance (0.1 mg readability) enables concurrent density determination and mass measurement without auxiliary equipment

Sample Compatibility & Compliance

The SFT-A1 accommodates standard cylindrical sample vessels (Φ50 mm), compatible with volatile organic solvents, aqueous surfactant solutions, polymer melts, and biological fluids. All Wilhelmy plates and Du Noüy rings are fabricated from corrosion-resistant platinum-iridium alloy and conform to dimensional tolerances specified in ISO 1409 Annex A. Calibration verification follows gravimetric and standard liquid protocols (e.g., ultra-pure water at 20 °C = 72.75 mN/m; 2-propanol = 21.7 mN/m). The system supports GLP/GMP workflows via password-protected user roles, electronic signatures, and tamper-evident audit trails compliant with FDA 21 CFR Part 11 requirements. Raw data files (.sft) are timestamped, version-controlled, and exportable in CSV, TXT, and PDF formats for third-party analysis or regulatory submission.

Software & Data Management

SFT-A1 v3.x software provides an intuitive, high-DPI graphical interface optimized for laboratory technicians and materials scientists. It features automated method selection (A3, A4, A5), dynamic baseline correction, automatic CMC detection algorithms, and customizable report templates aligned with ISO/IEC 17025 documentation standards. All measurement sessions include metadata capture: operator ID, environmental temperature/humidity (via optional external sensors), calibration history, and instrument firmware version. Data encryption, local database archiving, and scheduled backup to network drives ensure long-term traceability. Remote diagnostics and firmware updates are supported over Ethernet or USB, minimizing downtime during routine maintenance.

Applications

• Surfactant formulation development and quality control in personal care, agrochemical, and detergent industries
• Interfacial rheology screening for emulsion and foam stabilization studies
• CMC determination and adsorption isotherm modeling (Langmuir, Frumkin)
• Surface energy evaluation of polymer films and coatings prior to adhesion testing
• Biological membrane mimicry studies using phospholipid monolayers at air–water interfaces
• Quality assurance of cleaning agents, disinfectants, and pharmaceutical excipients per USP and EP 2.9.34

FAQ

Does the SFT-A1 support both ring and plate methods out-of-the-box?
Yes—the instrument ships with calibrated platinum-iridium Du Noüy rings and Wilhelmy plates, and the software automatically detects and configures the selected method based on hardware recognition.
Is temperature control included as standard?
Ambient-temperature operation is standard; optional Peltier heating (–10 °C to +80 °C) or external recirculating bath integration requires separate ordering of the thermal module kit.
Can raw force data be exported for custom analysis?
Yes—full-resolution force vs. position/time datasets are saved in ASCII format and can be imported into MATLAB, Python (NumPy/Pandas), or Origin for advanced curve fitting and kinetic modeling.
How is calibration traceability maintained?
Each unit includes a NIST-traceable calibration certificate for the force sensor and geometric dimensions; users may perform in-house verification using certified reference liquids and documented SOPs.
What operating systems are compatible with the SFT-A1 software?
The embedded controller operates independently; however, optional PC-based remote monitoring and batch reporting are supported on Windows 10/11 (64-bit) via TCP/IP communication protocol.