Publications 2024

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https://hdl.handle.net/20.500.14170/3704

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Browsing Publications 2024 by Department "Faculty of Electronic Engineering & Technology"
  • Publication
    Characterization of Excimer Laser Micromachining Parameters to Derive Optimal Performance for the Production of Polydimethylsiloxane (PDMS)-based Microfluidic Devices
    ( 2024-01-01)
    Shazlina Johari
    ;
    Ting Z.K.
    ;
    Mazlee Mazalan
    ;
    Yufridin Wahab
    ;
    Anas Mohd Noor
    ;
    Mohd Fairus Ahmad
    ;
    Muhammad Mahyiddin Ramli
    Laser micromachining has been used as an alternative to producing microfluidics structures and simplifying the conventional soft lithography process. In this paper we characterize the excimer laser micromachining parameters and demonstrate its application by producing several microfluidic structures in polydimethylsiloxane (PDMS). The parameters include the number of laser pulses, laser energy and rectangular variable aperture (RVA) in both x- and y-directions. We found that the laser energy and pulse rate affect the depth of micromachining d channels, while RVA in both x- and y-directions affects the width of the channels. Repetition of laser scan does not change the channel width but significantly changes the channel depth. Proper adjustment for laser energy and pulse rate is required to fabricate a desired channels depth. In order to demonstrate the microfabrication capability of an excimer laser with the optimal operating parameters, several microfluidic structures were micromachining d into PDMS with a KrF excimer laser.
      1
  • Publication
    Surface Modification of GO/TiO2 Thin Film by Sodium Dodecyl Sulphate for Photocatalytic Applications
    ( 2024-01-01)
    Azliza Azani
    ;
    Dewi Suriyani Che Halin
    ;
    Mohd Arif Anuar Mohd Salleh
    ;
    Kamrosni Abdul Razak
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Muhammad Mahyiddin Ramli
    ;
    Vizureanu P.
    ;
    Mohd Fairul Sharin Abdul Razak
    ;
    Sandu A.V.
    ;
    Mohamad N.
    Photocatalyst material titanium dioxide (TiO2) and graphene oxide (GO) were used to improve the self-cleaning properties of thin films. The sol–gel spin-coating method was successfully used to synthesize GO/TiO2 thin films. Surface modification was applied to optimize the self-cleaning capabilities by adding several concentrations of sodium dodecyl sulfate (SDS) (0.1 w/v%, 0.2 w/v%, 0.3 w/v%, 0.4 w/v%, and 0.5 w/v%) to the parent solution. The synthesized thin films were investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction, UV-visible spectroscopy, water contact angle analysis, and photocatalytic analysis. The AFM and SEM images revealed that as the SDS amount increased, the particles became less agglomerated, and the roughness of the surface reduced from 2.54 × 102 nm to 0.83 × 102 nm. The wettability analysis showed that when SDS increased to 0.4 w/v%, the water contact angle dropped to 15.30°, implying that the thin film exhibits hydrophilic qualities. A decrease in the GO/TiO2 band gap was obtained linearly with the increase in SDS addition from 3.17 eV to 2.75 eV. Finally, the improvement of the surface coating and reduction of the band gap enhanced the photocatalytic activity, which degraded 78.97% of methylene blue, which was obtained by 0.4SDS.
      2