Transportation Vehicle Light-Weighting with Polymeric Glazing and Mouldings

Transcription

1 Transportation Vehicle Light-Weighting with Polymeric Glazing and Mouldings Reinhold H. Dauskardt rganosilicate Films and Coatings Scott Isaacson, Joe Burg, Siming Dong, Michael Hovish, Florien Hilt Polymers and Hybrid Nanomaterials Jeff Yang, Marta Giachino, Qiran Xiao, Linying Cui, Zhenlin Zhao, Yichuan Ding Membranes for Fuel Cells and Batteries Daisy Yuen Complex Multi-Junction Device Structures Ryan Brock Photovoltaic and Flexible Electronic Materials Fernando Novoa, Chris Bruner, Stephanie Dupont, Nick Rolston, Warren Cui, Brian Watson Biological Hybrids Krysta Biniek, Jacob Bow, Chris Berkey, David Kanno DE-BES and AFSR programs on hybrid materials, BA PV Consortium, Stanford-GCEP program on lightweighting.

2 Processing and Thermomechanical Reliability of Hybrid Films light-weight vehicle touch display sensors and PV AR coatings wearable current polymeric glazings do not meet durability/performance requirements for near-term implementation Coatings and deposition methods need improvement Vacuum-based techniques: high cost and inconvenient Solution-based techniques: multiple steps, coating low crosslinking density, solvents pollution atmospheric plasma

3 utline Coating Reliability and Lifetimes coating characterization techniques for reliability accelerated testing and lifetime prediction Protective and Transparent Coating Systems controlling organosilicate molecular structure bi-layers with optimized adhesion and hardness strategies for incorporating UV protection Anti-Reflection Coating Systems single and graded layer strategies Transparent and Conducting Films applications for sensor and display technologies

4 Coating Reliability and Evolution of Defects damage propagates if mechanical stresses are large enough so that mechanical driving force G presence of chemical species and photons, damage propagates even if G environment and stress accelerates defect evolution Role of coupled stress parameters in coating reliability and lifetimes: H 2 mechanical stress diffusion temperature environmental species G G photons (photochemical reactions) c c J J 2 / m 2 / m cohesion or adhesion Coating Damage stress hn

5 Limitations of Thin-Film Adhesion Tests Indentation/Scratch Test - complex stress and deformation fields - principally qualitative results - (nano) scratch test even less quantitative Indenter Plastic zone Film Interface Crack Substrate Peel/m-ELT Test - difficult to apply loads - plastic deformation of film - temperature complications in m-elt P M Film Interface Crack Substrate Blister Test - compliant loading system - environmental effects - etching/machining of cavity difficult Substrate P Cavity in Substrate Film Major limitations: need detailed film properties, film stress relaxation and film plasticity principally qualitative results for all above methods!

6 Quantitative Adhesion/Cohesion and Debond Kinetics Crack Growth Rate, da/dt (m/s) P P substrate Fracture Energy, G c (J/m 2 ) Coating III Coating IV Fracture at interface between coating and PMMA Adhesion/Cohesion Fracture between epoxy and coating Near the interface but with some deflection into the PMMA PPG 1 PPG 3 PPG 5 PPG 2 PPG 2* PPG 4* PPG 6* substrate Degradation Kinetics (temp/environment /UV effects) UV intensity 1.2 mw/cm mw/cm 2 No UV 0 mw/cm 2 threshold crucial for reliability Strain Energy Release Rate, G (J/m 2 )

7 utline Coating Reliability and Lifetimes coating characterization techniques for reliability accelerated testing and lifetime prediction Protective and Transparent Coating Systems controlling organosilicate molecular structure bi-layers with optimized adhesion and hardness strategies for incorporating UV protection Anti-Reflection Coating Systems single and graded layer strategies Transparent and Conducting Films applications for sensor and display technologies

8 Atmospheric Plasma Deposition of Hybrid Films Innovation in Precursor Delivery dilution He flow bubbler He flow heated Capacitively precursor He Coupled and 2 flow supply line Plasma atmospheric plasma showerhead Dielectric Barrier Discharge Plasma gas heating coils bypass line precursors bubbler high temperature vaporizer higher molecular weight precursors higher boiling point larger range of material choices plasma substrate BTESE Si Si RF power low temperature afterglow He and N 2 plasma gas reactive species coating medium temperature N 2, 2, air plasma gas TES

9 Silica Coatings Deposited by Atmospheric Plasma Young's Modulus, E (GPa) 70 fused quartz TES 23 o C 60 TES 135 o C BTESE o C TMCTS (higher plasma power) 40 TMCTS Commercial sol-gel polysiloxane dense silica bridged silica Adhesion Energy, G c (J/m 2 ) bridged silica dense silica TES 23 o C TES 135 o C BTESE 135 o C TMCTS Commercial sol-gel polysiloxane Density, (g/cm 3 ) Deposition Rate (nm/min) Precursors studied: Si Si Si SiH H Si HSi HSi TES BTESE TMCTS ~100% visible transparency Cui, Dauskardt, et al., ACS Applied Mat Interfaces, Molecular bridging

10 Single Precursor Method - Hard and Adhesive Bilayer Integrate layers deposited under different conditions carbon-bridged organosilicate bottom layer exhibits excellent adhesion to PMMA dense silica top layer exhibits high hardness and scratch resistance Carbon bridged precursors dense silica tough organosilicate polymer substrate S i C H 2 n S i Adhesion energy to PMMA, G C (J/m 2 ) Adhesive organosilicate Commercial sol-gel polysiloxane Dense silica Bilayer Young's modulus, E (GPa) Cui, Dauskardt, et. al., ACS Nano, 2014.

11 Strategies for Highly Adhesive Multilayer Deposition Integrate multi-layers layers deposited under different conditions high toughness carbon-bridged organosilicate bottom layer dense silica top layer with high hardness and scratch resistance ~100% visible transparency Single precursor method graded or multi-layers organic precursor Processing Parameters inorganic precursor BTSE S i C H 2 n S i plasma conditions Multi-precursor method graded or multi-layers fast deposition dense silica tough silica TES widely used, cheap 1,5-cyclooctadiene easy ring opening and network former polymer substrate

12 Strategies for Highly Adhesive Multilayer Deposition Integrate bilayer deposition under single/dual precursors choice high adhesion organosilicate bottom layer and dense silica top layer ~100% visible transparency Single Precursor Method Dual Precursor Method Cui, Dauskardt, et. al., ACS Nano, Dong, Zhao, Dauskardt, ACS Appl. Mater. Interfaces, 2015.

13 utline Coating Reliability and Lifetimes coating characterization techniques for reliability accelerated testing and lifetime prediction Protective and Transparent Coating Systems controlling organosilicate molecular structure bi-layers with optimized adhesion and hardness strategies for incorporating UV protection Anti-Reflection Coating Systems single and graded layer strategies Transparent and Conducting Films applications for sensor and display technologies

14 Atmospheric Plasma and Anti-Reflection Coatings (ARC) Applications transportation windows sensor technologies ophthalmic lenses Architecture Single Layer Double Layer Multi-Layer n slarc = n sub n air n air n substrate = n2 1 n 2 2 Alternate n 1,n 2 from DLARC Single Layer Uncoated Surface Double Layer Multi-Layer

15 Atmospheric Plasma and Anti-Reflection Coatings (ARC) Single Layer ARC Metal xide ARC Silicon % Reflection Ta x decreasing thickness Bare Silicon 50 mm/s 70 mm/s 85 mm/s Significant AR reduction in both systems SLARC Average Reflectance Silicon 42% 38% Absolute Reflection Minimum Ta x <7% 1.90% Ti y <5% 0.3% % Reflection Ti y Wavelength (nm) decreasing thickness Bare Silicon 75 mm/s 85 mm/s 100 mm/s Wavelength (nm)

16 utline Coating Reliability and Lifetimes coating characterization techniques for reliability accelerated testing and lifetime prediction Protective and Transparent Coating Systems controlling organosilicate molecular structure bi-layers with optimized adhesion and hardness strategies for incorporating UV protection Anti-Reflection Coating Systems single and graded layer strategies Transparent and Conducting Films applications for sensor and display technologies

17 Deposition of Transparent Conducting Zn Thin Films light-weight vehicle touch display sensors and PV AR coatings wearable Characteristic features of Zn: - wide bandgap semiconducting material - high electric conductivity - high visible transmittance - abundant resource - replacement for Indium Tin xide (IT) atmospheric plasma deposition of Zn films in ambient air at low temperature on plastics.

18 Atmospheric Plasma Deposition of Transparent Conducting Zn Thin Films T v = 98% T v = 84% Zn films with a transmittance above 98% successfully obtained in ambient air at 25 ºC by atmospheric plasma deposition. - Precursor: Diethylzinc (Zn(C 2 H 5 ) 2 ) - Substrate: PMMA, PET, PC Watanabe and Dauskardt, rganic Electronics, 2014

19 Atmospheric Plasma Deposition of Transparent Conducting Zn Thin Films T v = 84% H-impurities as electron donors doping Watanabe and Dauskardt, rganic Electronics, 2014

20 Atmospheric Plasma Deposition of Transparent Conducting TiN x /Ti 2 Hybrid Films Visible transmittance ~80% and resistivity as low as 10-1 ohm cm successfully obtained in ambient air Precursor: titanium ethoxide on PC substrate Siming Dong and Dauskardt, Advanced Functional Materials, 2014

21 Summary Coating Reliability and Lifetimes coating characterization techniques accelerated testing and lifetime prediction Protective and Transparent Coating Systems current polymeric glazings/windoes do not meet durability/performance requirements hybrid coatings with optimized adhesion and hardness Anti-Reflection Coating Systems single and graded layer strategies Fracture Energy, G c (J/m 2 ) Coating III Fracture between epoxy and coating Coating IV Fracture at interface between coating and PMMA Near the interface but with some deflection into the PMMA PPG 1 PPG 3 PPG 5 PPG 2 PPG 2* PPG 4* PPG 6* Transparent and Conducting Films sensor and display technologies