Table 2.

Properties of sensing materials used in respiration sensors.

Metallic Material	Electrical Conductivity	Mechanical Properties
Silver-plated nylon yarn	Excellent	Flexible, soft, conformable
Conductive Textile and Fabrics	Excellent	Flexible, stretchable, comfortable
Conductive inks	Good	Flexible, adaptable
Polyethylene-co-vinyl acetate (PEVA)	Conductive with MWCNTs	Highly flexible
Polyimide-coated hollow-core silica glass capillaries with silver layer	Conductive with silver layer	Highly flexible
Multi-walled Carbon Nanotubes (MWCNTs)	Excellent	Flexible, high tensile strength
Graphene	High	Flexible, strong
MXene	Good	Flexible, mechanically robust
Carbon black nanoparticles	Good	Flexible, good resilience
Polyvinylidene Fluoride (PVDF)	Piezoelectric properties	Flexible, strong