Advanced Materials and Surface Engineering Lab

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The Advanced Materials and Surface Engineering Lab provides researchers in the Lamar University community with access to high-end instrumentation for the studies of material and surface properties. The lab is supervised by Dr. Chun-Wei Yao. The Advanced Materials and Surface Engineering Lab supports collaborative research projects with users from other Educational Institute and Industry. The lab also supports educational activities involving lab tours, workshops, hands-on demonstrations, outreach, and broader impact-related activities.

 

Instruments:

Atomic Force Microscope

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The atomic force microscope (AFM) is a scanning probe microscopy in which a sharp probe is scanned in a raster pattern across the sample surface to obtain information such as topography in three dimensions. Other information such as forces between the tip and the sample can also be measured using our AFM.  

 

Nanoindenter

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The Nanoindenter is a nanomechanical test instrument used for measuring the hardness and elastic modulus of materials. Our Triboindenter is equipped with dual head systems and enables testing at the nano/micro scale levels to provide great performance for nanomechanical testing.

 

3D Profilometer

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The 3D Profilometer is used to measure surface roughness, profiles, and step heights on both flat and curved surfaces.

 

Laser machining system

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The laser machining system is used for marking and engraving raw metal applications as well as industrial polymers. The system is ideal for applications that demand extreme precision.

 

Surface Analyzer

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Surface Analyzer provides a complete characterization of the surface energy, surface tension, contact angles, and surface hydrophobicity.

 

Contact Angle Measurement System with Temperature Control

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The system is used to perform contact angle measurement and determine the hydrophobicity, surface energy of solids at temperature from 5 to 300 °c. 

 

Tribometer

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The tribometer is used for accurate and repeatable wear, scrath, and friction testing. 

 

Corrosion Testing-Electrochemical Impedance Spectroscopy

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Electrochemical Impedance Spectroscopy (EIS) system provides very fast, accurate, nondestructive, and quantitative measurements of corrosion rates of materials at different solutions and evaluates the stability of coatings.

Projects

Bio-inspired Design

Hydrophobic surfaces which imitate the lotus architecture has a wide range of applications such as anti-icing and self-cleaning. The main objective is to fabricate and characterize nano/microstructured surfaces to study the underlying physical mechanisms responsible for enhanced hydrophobicity. The contact angle is the direct result of surface free energy minimization of the interfacial surfaces. Contact angle measurements were performed using a Goniometer for each engineered surface. Advancing, receding, and equilibrium contact angles were also measured. The technology could possibly be designed into an adhered coating for condensers to enhance dropwise condensation.

nanoparticle-based hydrophobic surface and structured hybrid surface
nanoparticle-based hydrophobic surface & structured hybrid surface

contact angle measurement

Anti-Corrosion & Anti-Fouling Coating

Corrosion and biofouling on metallic materials are serious problems. Up to now, various methods have been reported for developing anti-corrosion & anti-fouling coating on metallic surfaces. The majority of those methods has substantial limitations such as weak mechanical and wear stability. To face the challenges, Dr. Yao’s research team is working on different approaches to develop anti-corrosion & anti-fouling coatings. For example, Dr. Yao’s research team constructed nanostructured metallic surfaces (Fig. 2-4) by using chemical etching. Dr. Yao’s research team will continue to develop a simple, one or two step fabrication technique for anti-corrosion & antifouling coating.

Scanning electron micrographs of a nanostructured copper surface & atomic force microscope image of a nanostructured copper surface Image of anti-corrosion & anti-fouling surface (2 cm × 2 cm)

 

 

 

 



(A) Scanning electron micrographs of a nanostructured copper surface, (B) Atomic force microscope image of a nanostructured copper surface, (C) Image of anti-corrosion and anti-fouling surface (2cm x 2cm)

Vibration on a Water Droplet

This vibration-induced droplet shedding method could find use in condensers, where rapid removal of condensate droplets and enhanced heat transfer performance is highly desirable. Droplet shedding processes were experimentally characterized using a high speed imaging system. The effects of vibration of droplet shedding were also studied. Vibrations were induced using a one-dimensional vibration generator coordinated by a square wave function generator to control the period and amplitude of vibration. Vibration modes were adjusted until sufficient resonance can be observed in an effort to understand its effects on droplet shedding.

vibration of water results
(a)Experimental image and schematic drawing of the resonant frequencies for different droplet volumes, (b)Vibration-induced jumping motion of a 5 μl water droplet

Water Harvesting

As climate change continues and long-term weather cycles change, access to fresh water for individual and agricultural use will be increasingly threatened around the world. Desert species offer valuable models for bio-inspired engineering of water-to-surface interactions at the nano and micro scale. This project will study the physics that governs water harvesting on engineering surfaces. Specifically, Dr. Yao’s research team will investigate how nano/micropatterning of the surface combine to create a surface effective at both condensing and collecting water at the macro-scale. Dr. Yao’s research team is developing and evaluating innovative engineering surfaces for water harvesting.

SEM picture of the 50 μm spacing hybrid surface consisting of a micropillar array of hydrophobic and hydrophilic sites. The hybrid surfaces were fabricated through a photolithography process. The tops of the micropillars are hydrophilic. Bottom and side surfaces are hydrophobic. & Water droplets condense on the hybrid surface.
(A) SEM picture of the 50 μm spacing hybrid surface consisting of a micropillar array of hydrophobic and hydrophilic sites. The hybrid surfaces were fabricated through a photolithography process. The tops of the micropillars are hydrophilic. Bottom and side surfaces are hydrophobic. (B) Water droplets condense on the hybrid surface.

Recently Funded Projects

  • Anti-corrosive Superhydrophobic Top Coating-Analysis and Testing. Source of Support: Center for Midstream Management and Science (CMMS), TX State Supported, Lamar University

Journal Publications, Science Citation Index (SCI/SCI Expanded)

  1. Md. Hoque, C.W. Yao, I. Lian, J. Zhou, M. Jao, Y.C. Huang, "Enhancement of Corrosion Resistance of a Hot-dip Galvanized Steel by Superhydrophobic Top Coating," MRS Communications, 2022. (I.F. 2.93)
  2. A. Jena, Y. V. R. Bhimavarapu, S. Tang, J. Liu, R. Das, S. Gulec, A. Vinod, C.W. Yao, T. Cai, R.Tadmor, “Stages That Lead to Drop Depinning and Onset of Motion," Langmuir, 2022. (I.F. 4.33)
  3. D. Sebastian, C.W. Yao, L. Nipa, I. Lian, G. Twu "Corrosion Behavior and Mechanical Properties of a Nanocomposite Superhydrophobic Coating," Coatings, 2021. (I.F. 3.23)
  4. D. Sebastian, C.W. Yao, "Simultaneous Mapping of Nanoscale Topography and Surface Potential for the Study of Localized Corrosion in 2024-T3 Aluminum Alloy and Corrosion Resistance Introduced by a Superhydrophobic Coating," MRS Communications, 2021. (I.F. 2.93)
  5. C.W. Yao, S. Tang, D. Sebastian, R. Tadmor, "Sliding of Water Droplets on Micropillar-structured Superhydrophobic Surfaces," Applied Surface Science, 504, 144493, 2020. (I.F. 7.39)
  6. D. Sebastian, C.W. Yao, "Effect of Poly(dimethylsiloxane) binder in a silica-based superhydrophobic coating on mechanical properties, surface roughness, and wettability," MRS Communications, 2020 (I.F. 2.56) 
  7. D. Sebastian, C.W. Yao, I. Lian, "Multiscale Corrosion Analysis of Superhydrophobic Coating on 2024 Aluminum Alloy in 3.5 wt.% NaCl Solution," MRS Communications, 2020. (I.F. 2.56)
  8. S. Tang, C.W. Yao, R.Tadmor, D. Sebastian, "Lateral retention of water droplets on solid surfaces without gravitational effect," MRS Communications, 2020. (I.F. 2.56) 
  9. R.Tadmor, S. Tang, C.W. Yao, S. Gulec, S. Yadav, Comment on “Comparison of the Lateral Retention Forces on Sessile, Pendant, and Inverted Sessile Drops," Langmuir, 2020. (I.F. 3.88)
  10. P. He, C.W. Yao, "Simulating Contact Angle Hysteresis Using Pseudo-line Tensions," MRS Communications, 9(3), 1060-1066, 2019. (I.F. 2.56)
  11. S. Tang, Y. Bhimavarapu, S. Gulec, R. Das, J. Liu, H. N'guessan, T. Whitehead, C.W. Yao, R. Tadmor, "Droplets Sliding Down a Vertical Surface Under Increasing Horizontal Forces," Langmuir 35, 8191-8198, 2019. (I.F. 3.88)
  12. D. Sebastian, C.W. Yao, I. Lian, "Abrasion Resistance of Superhydrophobic Coatings on Aluminum Using PDMS/SiO2," Coatings 8 (11), 414, 2018. (I.F. 2.88)
  13. A. Azimi, P. He, C. Rohrs, C.W. Yao, "Developing a novel continuum model of static and dynamic contact angles in a case study of a water droplet on micro-patterned hybrid substrates," MRS Communications, 8 (10), 1445-1454, 2018. (I.F. 2.56)
  14. D. Sebastian, C.W. Yao, I. Lian, "Mechanical Durability of Engineered Superhydrophobic Surfaces for Anti-Corrosion," Coatings 8 (5), 162, 2018. (I.F. 2.88)
  15. Y. Chen, T. Li, Z. Jia, F. Scarpa, C.W. Yao, L. Wang, " 3D printed hierarchical honeycombs with shape integrity under large compressive deformations," Materials & Design, 137, 226-234, 2018. (I.F. 7.99)
  16. C.W. Yao, D. Sebastian, I. Lian, Ö. Günaydın-Şen, R. Clarke, K. Clayton, C.Y. Chen, K. Kharel, Y. Chen, Q. Li, "Corrosion Resistance and Durability of Superhydrophobic Copper Surface in Corrosive NaCl Aqueous Solution," Coatings 8 (2), 70, 2018. (I.F. 2.88)
  17. C.W. Yao, C.L. Lai, J. Alvarado, J. Zhou, K. Aung, J. Mejia, “Experimental Study on Effect of Surface Vibration on Micro Textured Surfaces with Hydrophobic and Hydrophilic Materials, ” Applied Surface Science, 412, 45-51, 2017. (I.F. 6.7)
  18. T.F. Wu, Y.C. Chen, W.C. Wang, A.S. Kucknoor, C.J. Lin, Y.H. Lo, C.W. Yao, I. Lian, “ Rapid Waterborne Pathogen Detection with Mobile Electronics, ” Sensors, 17, 1348, 2017. (I.F. 3.57)
  19. M.H. Liao, H.Y. Huang, F.A. Tsai, C.C. Chuang, M.H. Hsu, C.C. Lee, M.H. Lee, C. Lien, C.F. Hsieh, T.C. Wu, H.S. Wu, C.W. Yao, " The achievement of the super short channel control in the magnetic Ge n-FinFETs with the negative capacitance effect," Vacuum, 140, 63-65, 2017. (I.F. 3.62)