HARKE HARKE-PV35S Video-Based Optical Contact Angle Analyzer

Overview

The HARKE HARKE-PV35S is a precision-engineered video-based optical contact angle analyzer designed for quantitative characterization of solid-liquid interfacial behavior under controlled laboratory conditions. It operates on the principle of high-resolution silhouette imaging: a precisely dispensed liquid droplet is deposited onto a solid substrate, and its profile is captured using a parfocal zoom optical system coupled with a high-sensitivity CMOS camera. Geometric analysis of the droplet contour—based on established Young’s equation frameworks—enables calculation of static, advancing, and receding contact angles, as well as derived thermodynamic parameters including surface free energy, work of adhesion, and spreading coefficient. The instrument is engineered for reproducibility in ISO 19403-2 (2017) and ASTM D7334-compliant workflows, supporting both sessile drop and captive bubble methodologies via optional accessories. Its modular architecture integrates mechanical stability, optical fidelity, and software-controlled automation to meet the demands of QC laboratories, R&D centers, and academic surface science facilities.

Key Features

• Benchtop design with rigid aerospace-grade aluminum base and four-point leveling feet for vibration-damped operation
• Parfocal 0.75×–4.5× continuous zoom microscope objective—maintains focus across magnification range for consistent image sharpness
• High-resolution CMOS imaging system with real-time video capture, frame-by-frame playback, and time-stamped snapshot acquisition
• Motorized XYZ sample stage (±50 mm vertical, ±60 mm lateral, ±10 mm longitudinal travel) enabling precise droplet positioning and multi-site analysis
• Adjustable LED cold-light illumination system with uniform intensity distribution and glare-free edge lighting for optimal droplet contrast
• Integrated syringe pump-compatible dispensing module (optional) for automated, repeatable micro-droplet deposition
• Comprehensive contact angle analysis suite: tangent, circle-fit, ellipse-fit, and baseline-corrected circle methods with manual refinement capability

Sample Compatibility & Compliance

The HARKE-PV35S accommodates flat, rigid, or flexible substrates up to 350 mm × 350 mm in footprint and ≤25 mm in thickness—including wafers, polymers, coated metals, textiles, and biomaterial films. It supports ISO 19403-1 through -4 (Contact angle measurement — Part 1: Optical methods; Part 2: Sessile drop method; Part 3: Tilting plate method; Part 4: Captive bubble method), ASTM D7334 (Standard Practice for Surface Wettability Assessment), and ISO 8296 (Plastics — Polyolefin films — Determination of wettability). All measurement data—including raw images, annotated profiles, metadata (timestamp, operator ID, environmental conditions), and calculation logs—are stored in a structured binary format compliant with GLP audit trail requirements. Export formats include CSV, PNG, TIFF, and PDF for integration into LIMS or regulatory documentation systems.

Software & Data Management

The proprietary HARKE Contact Angle Analysis Software (v5.2+) provides a validated, menu-driven interface compliant with FDA 21 CFR Part 11 principles—including electronic signatures, role-based access control, and immutable audit trails for all measurement events. Core modules include dynamic contact angle tracking (advancing/receding), surface energy calculation via Owens-Wendt-Rabel-Kaelble (OWRK) and Wu harmonic mean models, interfacial tension derivation from pendant/sessile drop profiles, and statistical batch reporting. Data export supports automated generation of calibration certificates, compliance summaries, and trend charts. Software updates are delivered via secure HTTPS channels with SHA-256 integrity verification and version-locking for GxP environments.

Applications

• Quality control of hydrophobic/hydrophilic coatings in medical device manufacturing (e.g., catheter surfaces, stent polymer layers)
• Surface treatment validation for plasma, corona, or flame activation of polymeric packaging films
• Characterization of self-cleaning and anti-fouling surfaces in architectural glass and solar panel R&D
• Wettability assessment of battery electrode slurries and separator membranes in lithium-ion cell development
• Surface energy mapping of printed electronics substrates to optimize ink adhesion and film uniformity
• Biocompatibility screening of tissue engineering scaffolds via protein adsorption correlation studies

FAQ

What contact angle analysis methods does the HARKE-PV35S support?
The system implements tangent, circle-fit, ellipse-fit, and baseline-corrected circle algorithms—with both fully automated and user-guided refinement modes.
Is the software compliant with 21 CFR Part 11 for regulated environments?
Yes—the software includes electronic signature support, audit trail logging, and user permission tiers required for FDA-regulated QC and GLP/GMP workflows.
Can the instrument measure interfacial tension between two immiscible liquids?
Yes—using pendant drop or sessile drop analysis on liquid-liquid interfaces, with accuracy traceable to NIST-traceable calibration standards.
What is the maximum sample thickness accommodated on the stage?
The stage accepts samples up to 25 mm thick; height-adjustable lens positioning ensures optical focus across the full Z-range.
Does the system support automated sequential measurements across multiple sample locations?
Yes—via programmable stage movement and scheduled image capture, enabling unattended batch analysis of up to 99 predefined positions.