Operation

 
Masscal G1 QCM/HCC Calorimeter

Key Benefits

of the

Masscal G-Series
of Nanobalance/
Microcalorimeters

Unique Measurement Capabilities, Accuracy, Sensitivity, and Cost

  • Single instrument for all three high-sensitivity measurements:
    • Mass Change to ± 2 ng
    • Heat Flow to ± 0.5 µW
    • Loss Compliance (J")
  • Simultaneous measurements of inter-related properties on the same sample at the same time
  • Integrated control of gas mixtures and temperature to ± 0.001ºC
  • Easily mounted sample plates
  • No fluid baths or vacuum pumps
  • Sample temperatures up to 250 C
  • Integrated humidity generator for maximum RH accuracy
  • Droplet capture access and direct NVR measurement
  • Patent-pending ultra-accuracy QCM sensors

Research & Development

  • Characterize New Materials
  • Measure Gas-Surface Reactions
  • Determine Partition Coefficients and Sorption Enthalpies
  • Optimize Formulations
  • Monitor Curing and Drying
  • Measure Depositions, Adsorptions & Interstitial Storage
  • Determine Reaction Energetics
  • Characterize End-Use Properties
  • Predict Product Lifetime and Product Storage Requirements

Manufacturing & Process Control

  • Measure Critical Parameters while Simulating Process Conditions
  • Control Quality of Sensitive Raw Materials and Intermediates
  • Assure Quality of Final Products

Challenging Real-World Problems

  • Solve Surface Interface Problems
  • Identify Sources of Product Performance Problems
  • Detect the Buildup of Harmful Gases or Surface Contaminants
  • Improve your understanding of the interaction of thin films and surfaces with their environment in nature, the laboratory and in the hands of your customers

Operation of the Masscal Nanobalance/Microcalorimeters
G-Series, L1 and HT Models

PREPARE THE SAMPLE

The top surface of the Quartz Crystal Microbalance ("QCM") crystal must be coated with a thin uniform film that adheres to the gold electrode surface. Films of 1 - 2 cm2 area and 0.1 - 20 µm thickness are optimal. Methods of film preparation include spin-coating, spray-coating, dip-coating, drop-coating, electrochemical deposition, and self-assembled monolayer chemistry. Solids studied have included metals, many polymers, proteins, C60 and a derivative, and pharmaceutical film-coatings.

Sample chamber temperature can be set from ambient to 100ºC, regulated to ±0.001ºC.

Gas pressure is 1 psi above ambient, enough to establish a flow of 20 std cm3/minute through the gas temperature equilibrator and sample chamber.

Any program of gas composition versus time is achievable through two mass flow controllers under Masscal Control Software. The standard mode is stepwise changes in the concentration of the volatile component. A full program cycle can take 1-3 hours, but overnight runs are also feasible.

RUN THE EXPERIMENT

Use the Masscal Control Software on your computer to set up experimental conditions, including:

Sample Identification and Preparation Method
Data File Name and Details
Equilibration Time and Total Experimental Time
Isothermal Temperature(s) and Step Interval(s)
Gas Flow Rates
Data Sampling Rates

Lock in the Initial Crystal Oscillation using the Frequency Control on the front panel.

Click the Start button on the Masscal Control Software.

ANALYZE THE DATA

Equilibrium

For the sorption isotherm: determine initial mass of film from frequency shift of the QCM upon coating, and subsequent mass of the absorbing gas from the mass versus time trace.

For the sorption enthalpy: integrate the thermal power versus time trace to give the total heat absorbed for a given stepwise change in gas composition. Division by the corresponding mass change gives the sorption enthalpy at that mean gas composition.

Kinetics

A plot of the log of mass change versus time following a stepwise change in gas composition yields the diffusion coefficient of the gas in the thin film.

Viscoelastic Properties of the Film

Measurement of the change of motional resistance of the coated QCM can be utilized to follow changes in J", the loss modulus of the thin film, as the sample absorbs or desorbs gas.