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PhD Student

Yichuan Ding

Reliability Engineer; Apple

Research Interests

Organic-inorganic molecular hybrids are a distinct class of engineering materials that are extensively used in a variety of fields. Unlike conventional nanocomposites which are made of physical mixture of separated phases, the intimate mixing of the organic and inorganic components in molecular hybrids at the molecular scale leads to unique properties and functionalities that is not simply a sum of the individual components. We focused on better understanding the structure-property-processing interrelationship for molecular design of hybrids with desired properties.

High Performance Adhesives for Electronic Packaging

Hybrid molecular materials is well suited for bonding organic/inorganic (metals, metal-oxides, nitrides…) interface, mitigating moisture degradation and even stress migration. More attractively, these hybrid materials can be cost-effectively synthesized using solution-based sol-gel process and can be easily deposited via spin, dip, or spray techniques. Spray coating is most desirable for delivering large-area, uniform coatings on a variety of substrates through a simple and cheap process. We worked on exploiting the potential of a versatile spray coating deposition capability that is well suited to large-scale manufacturing. We demonstrated both bilayer and dual-source concurrent spray strategies and proved their ability for nanolength-scale control of the through-thickness film composition. Highly compositionally graded hybrid layers were achieved and optimized and showed to have improved interfacial film properties than homogeneous coatings. 

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Transparent Protective Coatings for Plastics

Due to their cost effectiveness, light weight, and great versatility, transparent plastics are used in a wide range of applications from optical lenses to automotive windows. However, because of the low surface hardness, they can be easily scratched which significantly reduces their transparency. Therefore, developing an effective transparent protective coating with both high hardness and adhesion properties is highly crucial. By combining spray deposition and atmospheric plasma deposition, we achieved a bilayer protective coating with an 8-fold improvement on adhesion energy and 5-fold enhancement on the Young’s modulus than the commercial poly-siloxane sol-gel coatings. The approach provides a strategy for unprecedented combination of adhesion and mechanical properties.

We are also developing new strategies to impart other functionalities to the mechanically robust protective coatings by co-depositing the functional nanoparticles (UV-absorbing, Conductive…) with the organosilicate matrix. 

Hybrids with Controlled Deformation Rate Sensitivity and Moisture Resistance

We focused on molecular design strategies for engineering the deformation rate and fracture resistance of organic-inorganic hybrid films in moist environments. By systematically manipulating the highly confined non-hydrolysable organic portion of the molecular network and characterizing the corresponding time-dependent crack growth in moist environments, we find some rather unique insights into the fundamental molecular-scale relaxation and cracking mechanisms. With increasing organic network connectivity, the mechanical behavior varied from almost perfectly elastic to increasingly viscoelastic, and furthermore, could be obtained in a controlled fashion.

Publications and Conference Proceedings

  • Y. Ding, Q. Xiao, R.H. Dauskardt, Molecular Design of Confined Organic Network Hybrids with Controlled Deformation Rate Sensitivity and Moisture Resistance, under review. 
  • Y. Ding, S. Dong, J. Han, D. He, Z. Zhao, R.H. Dauskardt, High Performance Optical Transparent Protective Coating for Plastics Using Dual Spray and Atmospheric Plasma Deposition, under review.
  • D. Chan, Y. Ding, R.H. Dauskardt, E.A. Appel, Engineering the Mechanical Properties of Polymer Networks with Precise Doping of Primary Defects, under review.
  • Y. Ding, R.H. Dauskardt, Spray Deposition of compositionally graded hybrid layers for high-performance adhesion, 2016 IEEE International Interconnect Technology Conference / Advanced Metallization Conference (IITC/AMC) (2016) 195-197.

Conference Presentations

  • Y. Ding, S. Dong, D. He, Z. Zhao, R.H. Dauskardt, Combining Spray and Atmospheric Plasma Deposition of Transparent Bilayer Protective Coatings on Plastics with Exceptional Adhesion and Hardness, ACS Meeting 2017, San Francisco, CA, April 2017.
  • S. Dong, Y. Ding, D. He, Z. Zhao, and R.H. Dauskardt, Dual Precursor Atmospheric Plasma Deposition of Organosilicate Transparent Functional Coating on Plastics, ACS Meeting 2017, San Francisco, CA, April 2017.
  • Y. Ding, R.H. Dauskardt, Spray Deposition of Compositionally Graded Hybrid Layers for High-Performance Adhesion, IITC 2016, San Jose, CA, May 2016.
  • S. Dong, Z. Zhao, Y. Ding, L. Cui, R.H. Dauskardt, Atmospheric Plasma Deposition and Durability of Transparent Functional Coatings, SystemX Conference, Stanford, November, 2015.
  • Y. Ding, R.H. Dauskardt, Compositionally and Fuctionally Graded Hybrid Layers for High-Performance Adhesion, AVS meeting 2015, San Jose, CA, October 2015.

Awards

  • O. Cutler Shepard Award, Stanford University (2016)
  • Enlight Foundation Graduate Fellowship, Stanford University (2014) 
  • Bronze Tablet, UIUC (2014)
  • Wert Scholarship, UIUC (2013)

Education

Ph.D Stanford University, Materials Science and Engineering, 2019
B.S. University of Illinois at Urbaa-Champaign, Materials Science and Engineering, 2014

Contact

650-646-8995