Membrane Journal (멤브레인)

The Membrane Society of Korea (한국막학회)
권호 표지

The Observation of Scattering Patterns During Membrane Formation: Spinodal Decomposition and Nucleation Growth

스피노달 분해와 기핵성장에 따른 상분리 과정의 광산란 패턴의 관찰

  • Kang, Jong-Seok (National Research Laboratory for Membrane, School of Chemical Engineering, College of Engineering, Hanyang University) ;
  • Huh, Hoon (National Research Laboratory for Membrane, School of Chemical Engineering, College of Engineering, Hanyang University) ;
  • Lee, Young-Moo (National Research Laboratory for Membrane, School of Chemical Engineering, College of Engineering, Hanyang University)
  • 강종석 (한양대학교 공과대학 응용화학공학부) ;
  • 허훈 (한양대학교 공과대학 응용화학공학부) ;
  • 이영무 (한양대학교 공과대학 응용화학공학부)
  • Published : 2002.06.01
Download PDF
⟨ Previous Next ⟩

Abstract

Small angle light scattering (SALS) and field emission scanning electron microscope (FE-SEM) have been used to investigate the light scattering patterns with time evolved during water vapor quenching (relative humidity of 53 (${\pm}3)%$ at $26^{\circ}C$ of polysulfone (PSf)/NMP/Alcohol and chlorinated poly(vinyl chloride) (CPVC)/THF/Alcohol, respective1y. Time dependence of the position of the light scattering maximum was observed at PSf dope solutions, confirming spinodal decomposition (SD), while CPVC dope solutions showed a decreased scattered light intensity with an increased q-value, indicating nucleation & growth (NG). For the each system, domain growth rate in the intermediate and late stage of phase separation decreased with increasing the number of carbon of alcohol used as additive (non-solvent). Also, in the early stage for SD, the scattering intensity with time was in accordance with Cahn's linear theory of spinodal decomposition, regardless of types of non-solvent additive. Also, the size scales obtained by SALS were mutually compared to domain sizes gained by FE-SEM measurement. These observations of scattering pattern were much clearly observed for the 20PSf/70NMP/10n-butanol (w/w%) and agreed with the theoretical predictions for scattering patterns of each stage like the early, the intermediate, and the late stage of SD type phase separation. As the scattering maximum was observed at the larger angles (larger q) in the order of n-butanol > n-propanol > methanol > no alcohol, the pore size of final morphology decreased.

Polysulfone (PSf/NMP/alcohol 용액과 chlorinated poly(vinyl chloride) (CPVC)/THF/Alcohol 용액에 대한 광산란 패턴을 SALS (Small angle light scattering)와 FE-SEM (field emission scanning electron microscope)을 이용하여 조사하였다. PSf 용액에서는 시간에 따라 q값의 최대 산란 강도를 보이는 광산란 거동을 나타내어 스피노달 (SD) 상분리 거동을 나타내는 반면, CPVC 용액에서는 q값이 증가함에 따라 광산란 강도가 줄어드는 핵성장 (NG) 거동을 나타냈다. 각 고분자 용액에서 상분리 중반과 후반부에서 비용매 첨가제로 사용된 알코올의 탄소수가 증가할수록 농도분극의 증가율은 줄어들었다. 또한, SD에서의 초반부의 시간에 따른 산란 강도는 비용매 첨가제의 종류에 무관하게 Cahn의 건형 이론에 잘 부합되었다. 또한, SALS 장치로 얻어진 기공크기와 전자현미경으로 얻어진 영역 크기는 상호간에 비교되었다. 20PSf/70NMP/10n-butano1 (w/w%) 용액에 대한 산란 패턴은 초기 상분리 거동에서부터 후기 거동까지 매우 선명하게 관측되었고, 초반, 중반, 그리고 후반부에 대한 SD에 대한 이론적 결과와 잘 일치하였다. 최고의 산란강도를 나타낸 각도의 크기는 n-butanol>n-propanol>methanol>no alcohol 순으로 관찰되었으며, 이 순서로 최종 형성된 막 단면의 기공 크기가 감소되는 것으로 조사되었다.

Keywords

References

  1. Basic Principles of Membrane Technology M. Mulder
  2. J. Membr. Sci. v.117 Phase separation processes in polymer solutions in relation to membrane formation P. van de Witte;P.J. Dijkstra;J.W.A. van der Berg;J. Feijen https://doi.org/10.1016/0376-7388(96)00088-9
  3. Dynamics of ordering processes in condensed matter S. Komura;H. Fukukawa
  4. Phase transition and critical phenomena v.8 J.D. Gunton;M. San Miguel;P.S. Sahni;C. Domb;J.L. Lebowitz
  5. Progress in Pacific Polymer Science v.2 Self-assembly of polymer blends at phase separation morphology control by pinning of domain growth T. Hashimoto;Y. Imanish(ed.)
  6. J. Membr. Sci. v.184 PMMA or PEO in THF.H₂O mixture;phase diagram separation mechanism and application E. Schuhmacher;V. Soldi;A.T.N. Pires https://doi.org/10.1016/S0376-7388(00)00624-4
  7. J. Appl. Polym. Sci. v.74 Membrane formation via phase separation induced by penetration of nonsolvent from vapor phase, Ⅱ. Membrane morphology H. Matsuyama;M. Teramoto;R. Nakatani;T. Maki https://doi.org/10.1002/(SICI)1097-4628(19991003)74:1<171::AID-APP21>3.0.CO;2-R
  8. Polymer v.39 Poly(ether imide) membranes obtained from solution in cosolvent mixtures K.V. Peinemann;J.F. Maggioni;S.P. Nunes https://doi.org/10.1016/S0032-3861(97)10067-2
  9. J. Appl. Polym. Sci. v.77 Phase separation mechanism during membrane formation by dry-cast precess H. Matsutyama;M. Nishiguchi;Y. Kitamura https://doi.org/10.1002/(SICI)1097-4628(20000725)77:4<776::AID-APP9>3.0.CO;2-Q
  10. Langmuir v.12 AFM and SALS characterization of spherulitic structure in polyethylene R. Viswanathan;D.W.M. Marr https://doi.org/10.1021/la950460j
  11. J. Membr. Sci. v.111 Evidence for spinodal decomposition and nucleation and growth mechanisms during membrane formation S.P. Nunes;T. Inoue https://doi.org/10.1016/0376-7388(95)00281-2
  12. Macromolecules v.31 Studies of liquid-liquid demixing of polystyrenes solutions using dynamic light scattering, nucleation and droplet growth from dilute solution J. Szydlowski;A. van Hook https://doi.org/10.1021/ma971776w
  13. Hanser, Munich Current topics in polymer science T. Hashimoto
  14. J. Polym. Sci., Polym. Phys. Ed. v.23 Phase separation phenomena in solutions of poly(2,6-dimethyl-1.4-phenylene oxide) in mixtures of trichloroethylene, 1-octanol and methanol;relationship to membrane formation J.G. Wijmans;H.J.J. Rutten;C.A. Smolders https://doi.org/10.1002/pol.1985.180230915
  15. Macromolecules v.30 The dynamics of thermal-induced phase separation in PMMA solutions P.D. Graham;A.J. Pervan;A.J. McHugh https://doi.org/10.1021/ma961720m
  16. J. Chem. Phy. v.42 Free energy of a nonuniform system. Ⅰ. Interfacial free energy J.W. Cahn;J.E. Hilliard https://doi.org/10.1063/1.1695731
  17. Polymer v.42 Small angle light scattering investigation of polymerization induced phase separation mechanisms J. Maugey;T. van Nuland;P. Navard https://doi.org/10.1016/S0032-3861(00)00743-6
  18. Marcromolecules v.34 Pressure-induced phase separation in polymer solutions;Kinetics of phase separation and crossover from nucleation and growth to spinodal decomposition in solutions of polyethylene in n-Pentane K. Liu;E. Kiran https://doi.org/10.1021/ma000816k