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1、微相分离在高分子科学的应用进展第1页，共23页，编辑于2022年，星期六Outline1.Concepts of Metastable states 2.2.Metastable states in single-component systemin single-component system3.3.Metastable states in polymer blend systemin polymer blend system4.4.Metastable states in polymer-solvent-nonsolvent systemin polymer-solvent-nonsol
2、vent system5.5.Conclusion第2页，共23页，编辑于2022年，星期六Equilibrium and stability in classical mechanicsEquilibrium and stability in classical mechanics(A)an unstable equilibrium;(B)a stable equilibrium;(C)a random equilibrium;and (D)a double-well,which includes one unstable equilibrium point surrounded by tw
3、o stable equilibrium points.Two filled dots represent the limit of stability.1.Concepts of Metastable states第3页，共23页，编辑于2022年，星期六Stable equilibrium and metastabilityStable equilibrium and metastability Metastablestate GEquilibriumstateAs a metastable state,it is stable with respect to infinitely sma
4、ll perturbations,but it may not be stable with respect to limited perturbations(overcome the free energy barrier G)towards a stable equilibrium state.G第4页，共23页，编辑于2022年，星期六A transformation from one stable state to another stable state will proceed through successive stages of metastable phases whene
5、ver such a metastable state exists.Phenomenologically,a metastable state may exist due to its fast kinetic pathway even through this state is thermodynamically less stable than the equilibrium state.OstwaldStephen Z.D.ChengCondensed states in polymeric materials:including transition thermodynamics,k
6、inetics,molecular motion in metastable states,crystal structure and morphology,liquid crystal polymers 第5页，共23页，编辑于2022年，星期六2.Metastable states in single-component systemin single-component systemPEO:NIF IF transition Cheng,S.Z.D.et,al.Macromolecule,1997,29:311327.第6页，共23页，编辑于2022年，星期六GibbsThomson:第
7、7页，共23页，编辑于2022年，星期六 Stephen Z.D.Cheng,2007,448:1006-1008.PE:crystal styles transition C.H.M.Weber,et.al.Nano Lett.,2007,7(7):2024-2029第8页，共23页，编辑于2022年，星期六Enantiotropic and monotropic phase behaviorsEnantiotropic and monotropic phase behaviorsEnantiotropic Phase BehaviorMonotropic Phase BehaviorGTd
8、TiMeltL.C.CrystalGTiTmMeltL.C.Crystal第9页，共23页，编辑于2022年，星期六One example of monotropic behavior in polymersOne example of monotropic behavior in polymersTang et al.Chem.Mater.,Vol.13,No.1,2001HOBT-C8 DSC cooling curves of HOBT-C8 DSC heating curves 第10页，共23页，编辑于2022年，星期六Single PhaseIdeal equilibriumtwo
9、 macroscopic phasesIn practical casedispersion phase(Metastable phase)3.Metastable states in polymer blend systemin polymer blend system0 GQ*QB1B2XB2XB1Miscible Mixture of A and B 第11页，共23页，编辑于2022年，星期六 G0B1B2XB2XB1S1S2Phase separated mixture of A and BBinodalSpinodalTwo PhaseMetastableRegionUCST ph
10、ase diagram第12页，共23页，编辑于2022年，星期六One-step phase separation Two-step phase separation Z.Wang et al.Polymer，2005，46：26752684 X.H.Zhang,et al.Macromolecules,Vol.39,No.21,2006第13页，共23页，编辑于2022年，星期六BP:Berghmans Point At BP,phase at concentrated side of the linevitrifies.Tg T BP Concentration of Polymer T
11、g becomes independent of concentration,and phase morphology is frozen in.Liquid-liquid phase separation Liquid-liquid phase separation with vitrification with vitrification第14页，共23页，编辑于2022年，星期六Liquidliquid phase separation Liquidliquid phase separation with crystallizationwith crystallizationCrysta
12、llizationTmTConcentration of PolymerC*A*B*ABM2M1M3M4Invariant LinePhase morphology of M1:Phase+crystal morphology of M3:第15页，共23页，编辑于2022年，星期六One example of liquid-liquid phase One example of liquid-liquid phase separation with crystallization separation with crystallizationX.H.Zhang.et,al.Rapid Com
13、mun.2005,26,1285Fluctuation-Assisted Crystallization第16页，共23页，编辑于2022年，星期六schematically diagram of liquid-liquid of polymer-solvent-nosovent4.Metastable states in polymer-solvent-nonsolventin polymer-solvent-nonsolvent第17页，共23页，编辑于2022年，星期六The composition path schematically diagram of the top of cas
14、ting film during the immersion precipitation process.C.-Y.Kuo et al./Journal of Membrane Science 315(2008)187194第18页，共23页，编辑于2022年，星期六(a)Phase diagram of BuOH/DCM/PLLA.(b)Process of porous fibers formationZ.Qi et al./Materials Letters,(2008),in press第19页，共23页，编辑于2022年，星期六进一步凝固进一步凝固国内外碳纤维质量的差异国内外碳纤维质
15、量的差异不是完全凝胶化不是完全凝胶化第20页，共23页，编辑于2022年，星期六H20 H20 H20 H20 H20 H20 H20 真正凝胶化真正凝胶化第21页，共23页，编辑于2022年，星期六 Transient states in polymer phase transformations;Identifications of phase in polymer crystal polymorphism;Monotropic liquid crystalline polymers;Metastable supra-molecular structures and self-assembled systems in polymer blends and copolymers;External field-induced metastability;5.Conclusion第22页，共23页，编辑于2022年，星期六Thanks for Your Attention!第23页，共23页，编辑于2022年，星期六