Rational design and evaluation of UV curable nano-silver ink applied in highly conductive textile-based electrodes and flexible silver-zinc batteries

The possibility of printing conductive ink on textiles is progressively researched due to its potential benefits in manufacturing functional wearable electronics and improving wearing comfort.However,few studies have reported the effect of conductive ink formulation on electrodes directly screen-printed on flexible substrates,especially printing UV curable conductive ink on common textiles.In this work,a novel UV curable nano-silver ink with short-time curing and low temperature features was developed to manufacture the fully flexible and washable textile-based electrodes by screen printing.The aim of this study was to determine the influence of ink formulation on UV-curing speed,degree of conversion,morphology and electrical properties of printed electrodes.Besides,the application demonstration was highlighted.The curing speed and adhesion of ink was found depending dominantly on the type of prepolymer and the functionality of monomer,and the type of photoinitiator had a decisive effect on the curing speed,degree of double bond conversion and morphology of printed patterns.The nano-silver content is key to guarantee the suitable screen-printability of conductive ink and therefore the uniformity and high conductivity of textile-based electrodes.Optimally,an ink formulation with 60 wt%nano-silver meets the potential application requirements.The electrode with 1.0 mm width showed significantly high electrical conductivity of 2.47×10^(6)S/m,outstanding mechanical durability and satisfactory washability.The high-performance of electrodes screen-printed on different fabrics proved the feasibility and utility of UV curable nano-silver ink.In addition,the application potential of the conductive ink in fabricating electronic textiles(e-textiles)was confirmed by using the textile-based electrodes as the cathodes of silverzinc batteries.We anticipate the developed UV curable conductive ink for screen-printing on textiles can provide a novel design opportunity for flexible and wearable e-textile applications.

Rheological properties and screen printability of UV curable conductive ink for flexible and washable E-textiles

As a critical component for the realization of flexible electronics,multifunctional electronic textiles(etextiles)still struggle to achieve controllable printing accuracy,excellent flexibility,decent washability and simple manufacturing.The printing process of conductive ink plays an important role in manufacturing e-textiles and meanwhile is also the main source of printing defects.In this work,we report the preparation of fully flexible and washable textile-based conductive circuits with screen-printing method based on novel-developed UV-curing conductive ink that contains low temperature and fast cure features.This work systematically investigated the correlation between ink formulation,rheological properties,screen printability on fabric substrates,and the electrical properties of the e-textile made thereafter.The rheological behaviors,including the thixotropic behavior and oscillatory stress sweep of the conductive inks was found depending heavily on the polymer to diluent ratio in the formulation.Subsequently,the rheological response of the inks during screen printing showed determining influence to their printability on textile,that the proper control of ink base viscosity,recovery time and storage/loss modulus is key to ensure the uniformity of printed conductive lines and therefore the electrical conductivity of fabricated e-textiles.A formulation with 24 wt%polymer and 10.8 wt%diluent meets all these stringent requirements.The conductive lines with 1.0 mm width showed exceptionally low resistivity of 2.06×10^(-5)Ωcm Moreover,the conductive lines presented excellent bending tolerance,and there was no significant change in the sample electrical resistance during 10 cycles of washing and drying processes.It is believed that these novel findings and the promising results of the prepared product will provide the basic guideline to the ink formulation design and applications for screen-printing electronics textiles.