Innovation driven by safety

Polymer Absorption (PA) Sensor Technology

Developed in close cooperation with the petroleum industry

Absorption of Hydrocarbons

About PA Sensors


Typically, a PAS is composed of an elastomeric polymer matrix that is embedded with micro- and nano-sized conducting particles. The resulting composite material is deposited between two electrodes on a printed circuit board (PCB) and has a characteristic baseline resistance. The PAS operates via absorption and subsequent matrix expansion (swelling) resulting from contact with target hydrocarbons. Upon swelling, the interparticle distance of the embedded conducting micro- and nanoparticles increases, resulting in a PAS baseline resistance change. If the detected resistance change is greater than an applied threshold, it can be used by an external system to trigger an alarm.

Historical Challenges

Commercially available PAS technologies have not changed considerably since they were first developed in the mid-1950s. Two main factors contributed to the developmental stagnation:

  1. material degradation from thermal and hydrolytic weathering, and
  2. cross-sensitivity to thermal fluctuations and water absorption (submersion/humidity).


Syscor has designed and produced a new generation of hydrocarbon leak detection PAS that overcomes historical challenges. The PAS is thoroughly tested and systematically qualified to reliably detect hydrocarbons (C4 and heavier) in air, underground, and within water bodies (including ice). Furthermore, it is designed to operate in a wide range of environments (icy, wet, humid, or dry) and temperatures.

  • Reliably detects butane (C4) and heavier hydrocarbons such as synthetic blends, dilbit, synbit, crude oil, gasoline, and diesel fuel
  • Methane immunity (no false alarms triggered by methane)
  • High signal-to-noise ratio
  • Moisture resistance
  • Minimal power usage
  • Possible to reuse after hydrocarbon contact (reversible)
  • Operating temperature:-40°C to +60°C (-40°F to +140°F)


PAS Application within Syscor Devices

Syscor’s Hydrocarbon Detector (HCD) and Hydrocarbon Detector with Water Level (HCDW) sensor probes are equipped with 3 PASs within perforated stainless steel enclosures. Up to two sensor probes may be wired to Syscor’s PCU-X01 Sensor Hub or PCU-X11 Inclinometer when deployed.

Syscor’s Rapid Deployment External Leak Detection System (RD-ELDS) utilizes 2 PASs within each HCD-P sensor probe, which have perforated high density polyethylene (HDPE) enclosures. Up to two sensor probes may wired to the RD-ELDS when deployed.


PAS surface topology images - what they show us

  • Figure A shows surface topology 3D rendering produced by an optical microscope used for surface roughness calculations; lighter colors represent higher surface amplitudes than dark colors (scale left of A).
  • Figure B shows a 2D rendering of Syscor's PAS surface topology; dark regions are lower in amplitude than light regions. Inset in Figure B presents contact angle measurements that show high surface hydrophobicity, rendering the polymer absorption sensors highly resistant to degradation from extended exposure to water and ice.
  • Figures C and D present cross-sectional scanning electron microscopy (SEM) scans of Syscor's PAS. The dark regions are voids within the sensor’s composite material; these voids help increase the PAS surface area for faster hydrocarbon detection kinetics. All scale bars = 100 μm.


PDF HCD Sensor Spec Sheet
PDF HCDW Sensor Spec Sheet
PDF Rapid Deployment External Leak Detection System (ELDS)