2 research outputs found
Anti-fouling TiO<sub>2</sub>‑Coated Polymeric Membrane Ion-Selective Electrodes with Photocatalytic Self-Cleaning Properties
Nowadays, using a polymeric membrane
ion-selective electrode (ISE)
to achieve reliable ion sensing in complex samples remains challenging
because of electrode fouling. To address this challenge, we describe
a polymeric membrane ISE with excellent anti-fouling and self-cleaning
properties based on surface covalent modification of an anatase TiO2 coating. Under ultraviolet illumination, the reactive oxygen
species produced by photocatalytic TiO2 can not only kill
microorganisms but also degrade organic foulants into carbon dioxide
and water, and a formed superhydrophilic film can effectively prevent
the adsorption of foulants, thus inhibiting the occurrence of biofouling
and organic fouling of the sensors. More importantly, residual foulants
could be fully self-cleaned through the flow of water droplets. By
using Ca2+-ISE as a model, an anti-fouling polymeric membrane
potentiometric sensor has been developed. Compared to the unmodified
electrode, the TiO2-coated Ca2+-ISE exhibits
remarkably improved anti-biofouling properties with a low bacterial
adhesion rate of 4.74% and a high inhibition rate of 96.62%. In addition,
the proposed electrode displays unique properties of anti-organic
dye fouling and a superior self-cleaning ability even after soaking
in a concentrated bacterial suspension of 109 CFU mL–1 for 60 days. The present approach can be extended
to improve the fouling resistance of other electrochemical or optical
membrane sensors and is promising for the construction of contamination-free
sensors
Dual-Channel Surface Waves Directional Radiation with Customizable Intensity and Switchable Pattern
Achieving
the conversion from surface waves (SWs) to propagating
waves has captivated long-standing interest, and various ingenious
metasurfaces benefiting from the powerful control capability for electromagnetic
waves are able to realize efficient SWs directional radiation. Nevertheless,
most existing schemes still suffer from the bottlenecks of single
radiation channel, uncontrollable radiation intensity, and immutable
radiation pattern, which immensely hinder their practical application
in high-integration intelligent devices. Herein, a series of appealing
strategies are proposed to achieve the dual-channel SWs directional
radiation with customizable radiation intensity and switchable radiation
pattern. The dual-channel SWs radiation metadevice based on the phase
modulation metasurface is designed to directionally radiate SWs in
left-handed circular polarized channel and right-handed circular polarized
channel and possesses the broadband frequency scanning characteristic.
More strikingly, the intensity-customizable dual-channel SWs radiation
metadevice loaded with lumped resistors can control the realized gain
of two circular polarized radiation beams, and the pattern-switchable
dual-channel SWs radiation metadevice loaded with PIN diodes can dynamically
adjust the radiation direction of the radiation beams. Numerous simulations
and experiments of the proof-of-concept prototypes with modular design
corroborate the theoretical predictions. Our methodology shows unprecedented
flexibility in regulating SWs directional radiation and has enormous
potential in engineering applications