Metallization on Textile by Electroless Plating with Pd or Pt Catalyzation in Supercritical Carbon Dioxide for Sensing Wearable Devise
Mitsuo Sano1, Yuma Tahara2, Tso-Fu Mark Chang1,3, Chun-Yi Chen1,3 , Tomoko Hashimoto2, Hiromichi Kurosu2, Masato Sone1,3 1Precision and Intelligence Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
2Department of Clothing Environmental Science, Nara Women's University, Kitauoya Higashimachi, Nara 630-8506, Japan 3CREST, Japan Science and Technology Agency, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
e-mail :[email protected]
Plating
Conditions
Ni-P bath NiCl2 9 wt.%
NaPO2H2 12 wt.% Complexing agent 12 wt.%
Ion-exchanged water 67 wt.% CO2 20 vol.%
C12H25(OCH2CH2)15OH (Surfactant : ELP-SCE) 0.2 vol.%
Pt bath
MATEX PLATINUM ELPt-2 51 vol.%
NH3 5 vol.%
Ion-exchanged water 44 vol.% Substrate Nylon 6,6 textile
Pressure Atmosphere (CONV) 15 Mpa (ELP-SCE)
Temperature 353 K
Plating time Ni-P:1, 20 min Pt: 3.5 h(CONV)
60 min (ELP-SCE)
Pd catalyzation (Pd-cat) PdCl2 100 mg/L
SnCl2 10 mg/L
HCl 87.5 g/L
Pretreatment time 10 s
Pd-SCC or Pt-SCC
Pd bis-acetylacetonate 3.2823×10-4 mol
Pt bis-acetylacetonate 5.085×10-5 mol
Pretreatment time 120 min
Temperature 353 K Pressure 15 MPa
Introduction
Materials
Acknowledgement This work has been supported by The Grant-in-Aid for Scientific Research (B) (JSPS KAKENHI Grant Number 26282013) and CREST Project operated by the Japan Science and Technology Agency (JST).
Conclusions • Uniform Ni coating on surface of each fiber was obtained when both the Pd-SCC and ELP-SCE were applied • Ni-P deposited on the textile by ELP-SCE after Pt-SCC. • Pt coating on surface of each Nylon 6,6 fiber was obtained by ELP-CONV after Pt-SCC.
Surface morphology and cross-sectional of Ni-P
Pd-cat+CONV: there were some pin-holes and cracks. Pd-SCC+ELP-CONV:no pin-hole and showed Ni coating on the surface of each fiber. But, there were a few peeled-off parts. Pd-SCC+ELP-SCE:no pin-hole with very smooth structure and showed Ni coating on the surface of each fiber.
Results and Discussion
Applications of wearable sensors Underwear →Detect alcohol level Sportswear →Track motion
One of the challenging points in wearable devices → Deposition of metallic materials on the textile
Electroless plating method can be applied in metallization of the textile
Wearable devices applied in various fields
Activity sensor
Heart sensor
Respiration sensor
Pretreatment
PI
(a)
(b)
(c) (d)
(e)
(f)
(i)
(j)
(g)
(h) PEEK coating
(a)CO2 gas tank (b)CO2 liquidization unit (c)Liquidizatrion unit (d)High pressure pump (e)Thermal bath (f) Reaction-cell (PEEK-lined SUS316L) (g)Substrate (h)Cross stirrer (i) Back pressure regulator (j) Trap
High pressure apparatus Experimental
Woo et al., Surf. Coat. Tech., 203 (2009) 1971–1978
Pd catalyst
Surface morphology of Pt by ELP-CONV after Pt-SCC
SEM Optical microscope
Pt catalyst
SEM
EDS
Ni-P deposition were invisible. However, Ni-P deposited on the textile was observed by SEM, and Ni was detected by EDS. Ni-P coating might be very thin .
100 μm
100 μm
10 μm
•Pt has high biocompatibility than Ni and Pd.
•Uniform Pt coating on surface of each fiber was obtained by ELP-CONV after Pt-SCC.
Conventional (CONV)
Etching is performed by toxic chemicals
Polymer
Electroless plating
Defects Cracks
Pd particle is deposited by PdCl2/SnCl2
Metal
Sc-CO2
Metal
Polymer
Supercritical CO2 (Sc-CO2)
It is not necessary to do etching
→ Toxic free → The fibers are not damaged
Metal is deposited from deep within the substrate
→Adherence of metal coating on the polymer
substrate is high
Process flow for electroless plating
Cat
Catalyst complex are soluble in
sc-CO2
Swelling polymer
Diffusion of complex
Sc-CO2 catalyzation (SCC)
Catalyst complex be transferred
into the polymer with the sc-CO2
CO2
ELP-SCE
ELP-CONV H2 bubble
Some voids
No voids micelle Micelle absorb
H2 bubble
Metal
Emulsified electrolyte
Surfactant
Sc-CO2
Electroless plating method with sc-CO2 emulsified electrolyte(ELP-SCE)
100 μm 10 μm
SEM
SEM
EDS
Pd-cat ELP-CONV
Pd-SCC ELP-CONV
Pd-SCC ELP-SCE
10 μm 10 μm 10 μm
100 μm 100 μm 100 μm
100 μm 100 μm 100 μm
Supercritical carbon dioxide (Sc-CO2)
Supercritical CO2 • High diffusivity • Low viscosity
It can improve transfer of materials into very fine space
Gas
Liquid Solid
Supercritical state
Critical point
7.38 Mpa 304.1K
Liquid & Gas Pr
essu
re
Temperature
Triple Point
Especially when applied on the human body, it is of great importance that the sensing system is biocompatible
→ Platinum has excellent biocompatibility.
WATAHA et al., Journal of Oral Rehabilitation 1996 23; 309-320