Phase Change Materials: Procedures

Polyethylene glycol and octadecane are two common phase change materials that can have melting temperatures near the temperature of the human body. The exact melting temperature of the material depends on molecular weight, among other factors. Because they give off heat while freezing, phase change materials have recently begun to be incorporated into clothing. The basic idea is that the material melts while the individual is warm or exercising and then freezes when they get cold, releasing heat. Incorporating phase change materials into the glove heaters will allow the gloves to give off some heat without consuming power. Phase change materials are incorporated into clothing by creating small microspheres. These are then encapsulated to prevent leakage and sandwiched between two thin layers of fabric, close to the skin. It is possible that the best solution for our gloves will come from a combination of both phase change materials and resistive heating.

Processing:
Step 1: Fabricate Microspheres. Click here for protocol.
Step 2: Encapsulation.
Step 3: Incorporate encapsulated microspheres into gloves.

Polyethylene Glycol:
We will be using polyethylene glycol with a molecular weight of 900g/mole manufactured by Fluka (Sigma-Aldrich). It has a melting temperature of 34.9 degrees Celcius.

Safety Information (from MSDS):
Disposal: Contact a licensed professional waste disposal service to dispose of this material.
Clean-up: Sweep up, place in a bag, and hold for waste disposal.
Response to Accidental Exposure: In case of contact with skin, immediately wash skin with soap and copius amounts of water. In case of contact with eyes, flush with water for 15 minutes and call a physician. If inhaled, remove to fresh air. If swallowed, wash out mouth with water and call a physician.
The complete MSDS for this material can be found here.

Octadecane:
Octadecane has the chemical formula C18H38. It has a melting temperature of between 28.5 and 29.3 degrees Celcius. Our octadecane is also manufacured by Fluka.

Safety Information (from MSDS):
Disposal: Dissolve or mix the materialwith a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber. Observe all federal, state, and local environmental regulations.
Clean-up: Sweep up, place in a bag, and hold for waste disposal.
Response to Accidental Exposure: In case of contact with skin, flush with water. In case of contact with eyes, flush with water for 15 minutes and seek medical advice. If inhaled, remove to fresh air. If swallowed, wash out mouth with water and call a physician.
The complete MSDS for this material can be found here.

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