Table 3.

Summary of representative materials, substrates, mechanisms, and fabrication procedures.²⁸

Sensor type	Materials	Substrates	Mechanism	Fabrication
Respiratory/breath	Graphite, SiO2 Graphite Silicon-nanocrystal CNTs PVDF-TrFE ZnO, Au	Cellulose Acetate Paper PI PDMS PDMS PI (nanoporous)	Humidity Conductometric Humidity Strain Piezoelectric Impedance	Hand-painting Hand-painting Spin coating Laser Scribing Molding E-beam, Sputtering
Temperature	CaCl2, Aliphatic Diols Graphene, Ag, PDMS Graphene/PEDOT-PSS	PLA PET Polyurethane	Conductometric Resistive Resistive	Injection Transfer Printing Inkjet Printing
Pressure and strain	MWCNTs, Al2O3, Cu, CNTs Conductive self-healing hydrogel SWCNT/paper, Au, PDMS	PI PDMS PDMS PI	Pressure/TFTs Piezoresistive Piezoresistive Piezoresistive	ALD Vacuum Deposition Casting 3D printing E-beam evaporation
Hydration	Graphene, Ag/AgCl Ag, PDMS Ag/AgCl	PMMA PDMS PET	Impedance Impedance Electrochemical	Wet transfer, Dry Patterning Drop Casting Screen Printing
Pulse rate	Graphene oxide PEDOT-PSS, PVDF-TrFE PVDF-TrFE, Al, Ag Graphene oxide, Au	PET, PI PEN PI Fabric (facemask)	Conductometric Piezoelectric Piezoelectric Humidity	Transfer printing Screen printing LBL Drop casting
Gas sensors	AgNPs, Carbon, CNT Reduced graphene Oxide Ag, Au	Silk PET PI	Chemirsistive Chemirsistive Chemirsistive	Spray and Drop Coating Drop casting, Spin coating Inkjet printing
Alcohol/acetone	ZnO, TiO2, Cu Au, ZnO ITO, ZnO	Alumina PI PET	Chemiresistive Chemiresistive Chemiresistive	Screen printing E-Bean, sputtering Drop casting, Laser ablation
Motion and activity Monitoring	Carbon black Carbon, Ag MWCNT, Cu MWCNTs,	Polyurethane PDMS,Cotton PDMS Polyurethane	Strain, conductivity Strain Strain Piezoresistive	Drop and dry Impregnation, Casting Casting 3D printing