Table 3 Respiratory sensors for respiratory pattern detection pattern.

RH

PU/ACNTs NFs

ultrasonication

5,11,16,20,29 with the RH of 11,33,59,75,95%

²⁵⁰

ZnO/Ti/PTFE

hydrothermal method, layer by layer coating

1.8,13.9,28,44.8,85% with the RH of 50,60,70,80,90%

²⁵¹

LIG/ poly(ether-ether-ketone)

laser ablation, depositing, sputtering

R=1700kΩ/% RH

²⁵²

SMPCF

Etch, self-assembly

Color changes with 0.02% RH

²⁵³

Borophene–MoS₂

in situ van der Waals assembly

LOD>0.9736%RH,

R= (0.245X-0.549)³

²⁵⁴

rGO/MoS₂

modified Hummer’s method, ultrasonication

LOD>0.0109%RH,

R=28.4RH-127.0

²⁵⁵

Borophene–graphene

in situ thermal decomposition

Ln R=2.992ln (RH)-4.637

²⁵⁶

rGO/PDAC

Layer by layer assembly

R=0.00143x + 0.975

²⁵⁷

MoS₂/LIG

laser ablation

R=8% (0−50%RH),

R=80%(50−100%RH)

²⁵⁸

Strain

rGO/CNTs

ultrasonic nanosoldering method

34.69@1%strain,

R=1.21 kPa⁻¹

²⁵⁹

MXene@spheres

wet-spinning, electrostatic assembly, spray-coating

R=174 (strain in 0-30%),

1187 (strain in 30-110%)

²⁶⁰

PU/rGO/PDA/PFDT

Electrospinning, chemical methods

2,9,50 with the strain of 20,50,100, respectively

²⁶¹

GO/CNT

Self-assembly, freeze-drying method

R=0.15 (strain in 0-50%),

0.58 (strain in 50-80%)

²⁶²

PANI-gelatin

sol-gel

R=1.4 (strain in 0-764.4%)

²⁶³

pressure

rGO/CNTs

ultrasonic nanosoldering method,

R=1.21 kPa⁻¹

²⁵⁹

nano carbon

drop casting method

R=31.63 kPa⁻¹ (0-2 kPa)

²⁶⁴

TPU/CB

screen-printing

R=5.205 kPa⁻¹ (0-2 kPa),

0.63 kPa⁻¹ (>1200 kPa)

²⁶⁵

PVDF/ZnO NFs

Electrospinning, magnetron sputtering

R=3.12 mV /kPa

²⁶⁶

MXene/rGO

freeze-casting, annealing polymerization

R=0.28 kPa⁻¹(0-66.98 kPa)

²⁶⁷

MXene ink-SF

dip-coating metho, screen-printing, etch

R=298.4kPa⁻¹(1.4-15.7 kPa)

171.9kPa⁻¹(15.7-39.3 kPa)

²⁶⁸

CPDMS

Spraying, coating

R=124 kPa⁻¹(2−200 Pa), 0.39 kPa⁻¹(0.2−12 kPa), 0.02 kPa⁻¹ (12−50 kPa)

²⁶⁹

3D graphene

chemical vapor deposition

R=110 kPa⁻¹(0−0.2 Pa),

3kPa⁻¹(0.2−15 kPa),

0.26 kPa⁻¹ (15−75 kPa)

²⁵

rGO/PC/W

Hydrothermal method, annealing

R=0.0122-0.41 kPa⁻¹ (2-1200 kPa)

²⁷⁰

a-PAN/G

Electrospinning, Annealing

R=44.5kPa⁻¹(0−1.2 kPa)

²⁷¹

MXene/Fe₃O₄/graphene

thermal chemical vapor deposition, coating, etching

R=4.71 kPa⁻¹ (0-62.5 kPa)

²⁷²

Laser-reduced graphene oxide

Lasering

R=0.95 kPa⁻¹ (0-14 kPa)

²⁷³