1. Complex Fluids & Molecular Rheology Laboratory, Department of Chemical Engineering, National Chung Cheng University, Chia-Yi 621, Taiwan, R.O.C. Chi-Chung Hua ( 華繼中 ) at NCCU Cheng-Kuang Lee ( 李正光 ) at Academia Sinica Show-An Chen ( 陳壽安 ) at NTHU Nanomorphologies in Conjugated Polymer Solutions and Films for Application in Optoelectronics: Experiments and Multiscale Computations

2. Background Typical procedures for fabricating PLED devices or polymer-based solar cells:  C.K. Lee and C. C. Hua, in Optoelectronics - Materials and Techniques, edited by P. Predeep (InTech, 2011), Chap. 10. (InTech, 2011), Chap. 10.

3. Conjugated Polymer vs. Commercial Polymer Solutions?

4. Atomistic Dynamics (AMD) Simulation Simulation information and conditions Initial chain configurations: all in parallel with the xy plane (not created by MC simulation ) (not created by MC simulation ) Force field: DREIDING Ensemble: NPT System temperature: 298 K System pressure: 1 atm Time step: 1 fs Total step: 100,000 (=100 ps) PC nodes and simulation time: 16 CPU, 28~30 hours System No. of chains of monomer units No. of solvents Density （ g/cm 3 ） Figure (a) Figure (b) Figure (c) PS (n=50) × 5 MEH-PPV (n=20) × 5 Cyclohexane × 1280 Chloroform × 2000 Toluene × 1152 1.40 0.90 0.99 The density was set to above, close to the normal pressure density at 298 K. (b) MEH-PPV / Chloroform (c) MEH-PPV / Toluene (a) PS / Cyclohexane ca 70 Angstrom 4 Hua, C. C.; Chen, C. L.; Chang, C. W.; Lee, C. K.; Chen, S. A., J. Rheol. 2005, 49, 641. Hua, C. C.; Chen, C. L.; Chang, C. W.; Lee, C. K.; Chen, S. A., J. Rheol. 2005, 49, 641.

5. Parameter-Free, Predictive Multiscale Simulations (1) Atomistic model & MD simulation (2) Monomer model & CGMD/LD simulation (3) Ellipsoid-chain model & MC simulation (4) Bead-chain model & BD simulation (5) Dumbbell model & BD simulation Coarse- graining Coarse- graining Coarse- graining Linking Quantum chemistry calculation Shie, S. C.; Hua, C. C.; Chen, S. A., Macromol. Theor. Simul. 2007, 16, 111. Shie, S. C.; Lee, C. K.; Hua, C. C.; Chen, S. A., Macromol. Theor. Simul. 2010, 19, 179. Lee, C. K.; Hua, C. C.; Chen, S. A., J. Chem. Phys. 2010, 133, 064902. Lee, C. K.; Hua, C. C., J. Chem. Phys. 2010, 132, 224904. Lee, C. K.; Hua, C. C.; Chen, S. A., J. Phys. Chem. B 2009, 113, 15937. Lee, C. K.; Hua, C. C.; Chen, S. A., J. Phys. Chem. B 2008, 112, 11479. Hua, C. C.; Chen, C. L.; Chang, C. W.; Lee, C. K.; Chen, S. A., J. Rheol. 2005, 49, 641. Lee, C. K.; Hua, C. C.; Chen, S. A., Macromolecules, 2011, 44, 320–324 Lee, C. K.; Hua, C. C, Optoelectronics / Book 1,( InTech, ISBN 978-953-307-276-0) Lee, C. K.; Hua, C. C.; Chen, S. A., (to be submitted).

6. Coarse-graining (mapping) procedures Coarse-graining (mapping) procedures MEH-PPV PANI-EB Lee, C. K.; Hua, C. C.; Chen, S. A., J. Phys. Chem. B 2008, 112, 11479. Lee, C. K.; Hua, C. C.; Chen, S. A., J. Phys. Chem. B 2009, 113, 15937 CG Model Potentials Constructed:

7. Single-Chain Statistics and Solvent Quality

8. (MEH-PPV) Single-chain properties computed by CGLD simulations Snapshots (300-mer) In Chloroform In Toluene Scaling Law Solvent quality Lee, C. K.; Hua, C. C.; Chen, S. A., J. Phys. Chem. B 2008, 112, 11479.

9. Quenched-Chain Morphology vs. Memory Effect?

10. vdw + HB + π-πvdw only Single-Chain Conformations of Conducting Conjugated Polymers from Solution to the Quenching State: A Multiscale Simulation CK Lee, CC Hua, and SA Chen, J Phys Chem B 2009, 113, 15937 ; Macromolecules 2011, 44, 320 ( CK Lee, CC Hua, and SA Chen, J Phys Chem B 2009, 113, 15937 ; Macromolecules 2011, 44, 320 ) PANI-EB MEH-PPV Vacuum (V)Chloroform (CF) Chlorobenzene (CB) Toluene (T) Mixed CF and T Mixed CF and CB

11. Super-Long Chains and Multi-Chain Aggregates

12. 10% defect5% defect0% defect 10% defect5% defect0% defect An Ellipsoid-chain Model for Conjugated Polymer Solutions Snapshots of single chain and aggregate cluster The predicted scaling laws for mean end-to-end distance (ETE) of MEH-PPV In toluene solution (T) In chloroform solution (C) M/C CGMC;slope = 0.41 ± 0.03 CGLD;slope = 0.41 ± 0.02 CGMD;slope = 0.38 ± 0.02 M/T CGMC;slope = 0.33 ± 0.03 CGLD;slope = 0.33 ± 0.02 CGMD;slope = 0.32 ± 0.01 M/(C+T) CGMC;slope = 0.34 ± 0.01 CGLD;slope = 0.37 ± 0.02 CGMD;slope = 0.46 ± 0.01  C. K. Lee, C. C. Hua, and S. A. Chen, J. Chem. Phys. 136, 084901 (2012). J. Chem. Phys. 136, 084901 (2012).

13. Experimental: Viscometrics, Light Scatterings, and Flow Turbidity

14. Constant-temperature aging: Time dependence Thermal annealing: Thermal irreversibility Viscometric Features of MEH-PPV Solutions 5mg/ml 5mg/ml Hua, C. C.; Chen, C. L.; Chang, C. W.; Lee, C. K.; Chen, S. A., J. Rheol. 2005, 49, 641 Hua, C. C.; Chen, C. L.; Chang, C. W.; Lee, C. K.; Chen, S. A., J. Rheol. 2005, 49, 641.

15. Controlling bulk aggregation state in semiconducting conjugated polymer solution Photoluminescence Spectra MEH-PPV/toluene MEH-PPV/chloroform wavelength (nm) intensity (a.u.) g (1) (τ) τ(μs) 1 mg/ml MEH-PPV/toluene τ(μs) 3 mg/ml MEH-PPV/toluene Without filtration 3 mg/ml MEH-PPV/chloroform g (1) (τ) τ(μs) With filtration Without filtration Dynamic Light Scattering C. C. Hua, C. Y. Kuo, S. A. Chen, Appl. Phys. Lett. (2008) θ = 90 °

16. Stabilization of bulk aggregation state in semiconducting polymer solutions Experimental set-up 0.02 mg/ml Shear rate = 1,516 s -1 t (μs) τ T /c (cm 2 /g) 0.3 mg/ml Shear rate = 1,516 s -1 t (μs) 1 mg/ml Shear rate = 1,516 s -1 Before shear t (μs) τ T /c (cm 2 /g) 3 mg/ml Shear rate = 1,516 s -1 C. C. Hua, C. J. Lin, Y. H. Wen, S. A. Chen, J. Poly. Res. (2011) Flow turbidity measurement-MEH-PPV/DOP Dynamic Light Scattering MEH-PPV/DOP g (1) (τ) τ(μs) θ = 90 °

17. 1 mg/ml MEH-PPV/toluene translationalinternal 1 mg/ml MEH-PPV/chloroform Dynamic structure factor for MEH-PPV Solutions Suppressed Internal Motions of MEH-PPV Aggregates The range of experimental values for polystyrene/toluene solutions MEH-PPV/toluene MEH-PPV/chloroform Yu H. Wen, Po C. Lin, Chi C. Hua, Show A. Chen, J. Phys. Chem. B 2011, 115, 14369 Yu H. Wen, Po C. Lin, Chi C. Hua, Show A. Chen, J. Phys. Chem. B 2011, 115, 14369. Prediction for Gaussian coil MEH-PPV/toluene Mixed Dynamics (Internal + Diffusive)

18. Conjugated Polymer Gel in Mixing Solvents DLS/SLS Light Scatterings 50 °C g1(τ,q)g1(τ,q)g1(τ,q)g1(τ,q) 9 mg /ml MEH-PPV solution (Chlorobenzene : Nonane = 5 : 3 ) 30 °C _aging 6 hr tq 2 (s/ μm 2 ) 30 °C _aging 25 hr Slope = -1 Slope = -2 Rheological Features g1(τ,q)g1(τ,q)g1(τ,q)g1(τ,q) tq 2 (s/ μm 2 ) q(nm-1) R q (cm -1 ) Aging process at 30 °C Strain = 0.1, frequency = 1 MD Simulation g1(τ,q)g1(τ,q)g1(τ,q)g1(τ,q)

19. Summary Considerable progress has been made in understanding single- chain/aggregate properties of typical conjugated polymer solutions. The molecular origins of the “memory effect” dictating the quenching morphologies have been partly unveiled Much remains to be explored, especially the bulk aggregation properties in solution, as well as the impacts of flow processing and solvent evaporations.