CV of Jun XU

Jun Xu, Dr.

Associate Professor

Institute of Polymer Science & Engineering

Department of Chemical Engineering

Tsinghua University,

Beijing 100084, China

 

Tel：86-10-62784740

Fax：86-10-62784550

Email: jun-xu@tsinghua.edu.cn

 

Education

1992 - 1997: Undergraduate study, Department of Chemical Engineering,

Tsinghua University.

1997 - 2002: Ph. D. Study, Department of Chemical Engineering,

Tsinghua University.

Supervisor:  Prof. Zeng-Ming Zhang, Prof. Guo-Qiang Chen

Professional Experience

2002 - 2005:  Assistant Professor, Department of Chemical Engineering,

Tsinghua University.

2005 - Present: Associate Professor, Department of Chemical Engineering,

Tsinghua University.

2011.2- 2012.1:   Alexander von Humboldt Research Fellow, Institute of Physics,

University of Freiburg, Germany,

Host: Prof. Günter Reiter

 

Teaching courses:

Polymer Processing and Applications

Lab course of Polymer Physics

 

Research interest:

  1. Polymer Crystallization ：

(1) The real-time process and mechanism of lamellar twisting in the banded spherulites

The real-time growth process of twisting crystals were observed in situ under atomic force microscope. The twisting details and branching of lamellae were clearly revealed.

 Figure 1. Real-time AFM phase images showing lamellar twisting The mark “E” indicates edge-on lamella and “F” indicates flat-on lamella. The arrows indicate screw dislocations contributing to backward growth. (Collaborated with Prof. Lin Li, published in Macromolecules, 2004, 37, 4118-4123.)

 (2) Expression of chirality in polymer crystals on different structural levels.

Figure 2.   Chiral growth of lamellar crystals of poly(D-lactide)

 

 

Figure 3.   Twisting chirality of lamellar crystals in poly(R-3-hydroxyvalerate) depends on the radial growth axis: Lamellae twist in left-handed sense along the a axis and they twist in right-handed sense along b axis.（Macromolecules 2009, 42, 694-701）

 (3) Characterization of semi-crystalline polymers via novel optical techniques, such as second harmonic generation imaging (collaborated with Prof. Hui Ma and Prof. Ping Xue, Department of Physics) and Mueller matrix microscopy (collaborated with Prof. Bart Kahr, New York University, USA).

(4) Chain conformation and crystallization of macromolecules confined in nano channels.

 

 

Figure 4. Transformed crystal (with elliptical boundary) in the matrix of metastable poly(ethylene oxide)/urea inclusion compound.

(5) Molecular process of nucleation of polymer crystallization: Experiments and theoretical modelling

Figure 5. Hoffman-Weeks plot with changing slope (a) and the corresponding crystallization line and melting line (b).

Figure 6. Scheme showing the secondary nucleation process of polymer lamellar crystals and the effect of lamellar width (w) on melting. (a) Secondary nucleation and growth of individual lamellar polymer cluster at the growth front, (b) coalescence of neighboring lamellar clusters provides another stabilization method of the newly formed lamellar clusters. (c) Scheme showing the effect of width of crystalline clusters on the melting line. （Macromolecules, 2016, 49, 2206−2215）

     2. Structure-property relation in polymeric material

(1) Structure and properties of biodegradable polyesters

(2) Structure and properties of polymer-based nanocomposites

(3) Polymers for commercial 3-D printing

  3. Biodegradable and biobased polymers

(1) Polyhydroxyalkanoates (PHA) and polylactide (PLA)

(2) Poly(butylene succinate) (PBS) and its copolymers.

(3) Biomimetic and smart polymer materials

 

   4. Polymer materials for energy storage

(1) Microporous polyolefin films for lithium battery

(2) Dielectric polymer nanocomposite film

(3) Solid polymer electrolyte

Research Projects：

  1. National Key R&D program of China (Grant No. 2017YFB0309301): Research on fundamental questions in preparation and properties of polylactide fibers, PI of sub-project, 2017-2021;
  2. National Natural Science Foundation Project： Study on crystallization mechanism of polymers via a new miscroscopic kinetics model, Principal, 2014-2017;
  3. 973 project: Polymer materials for energy dissipation (subproject), 2016-2018;
  4. Joint project from Sino-Germany Center for Science Promotion： Concepts for controlling nucleation in systems of biodegradable polymers， Principal, collaborated with Prof. Günter Reiter, Germany, 2013-2015；
  5. “863” High Technology Project: Industrialization of poly(butylene succinate) derived from biobased monomers and post chemical synthesis， Participant, 2011-2015 ；
  6. Modelling of heat sealing process, Principal;
  7. Modelling of rubbers, Principal,;
  8. Industriallization of poly(butylene succinate) and its copolymers, collaborated with incorporations.

Awards:

Alexander von Humboldt Research Fellowship for Experienced Researchers

Feng Xingde Polymer Prize for winning "The Best Paper Nomination from China" published in the journal of Polymer in 2011

New Century Excellent Talents in University

ACS 3-year membership award

Representative Publications:

  1. Gao Y, Yao SF, Ye HM, Guo BH, Xu J*. Orientation of polymer chains in spherulites of poly(ethylene oxide)-urea inclusion compounds. Polymer 2017, 130, 209-217.
  2. Zhong Z, Yang XT, Guo BH, Xu J*, Huang YB*. Dissolution behavior of the crystalline inclusion complex formed by the drug diflunisal and poly(ε-caprolactone). Cryst. Growth Des. 2017, 17, 355−362.
  3. Xu J*, Heck B, Ye HM, Jiang J, Tang YR, Liu J, Guo BH, Reiter R, Zhou DS, Reiter G. Stabilization of nuclei of lamellar polymer crystals: Insights from a comparison of the Hoffman−Weeks line with the crystallization line. Macromolecules, 2016, 49, 2206−2215.
  4. Song YY, Ye HM*, Xu J*, Hou K, Zhou Q, Lu GW. Stretch-induced bidirectional polymorphic transformation of crystals in poly(butylene adipate). Polymer 2014, 55, 3054-3061.
  5. Ye HM, Wang RD, Liu J, Xu J*, Guo BH*. Isomorphism in Poly(butylene succinate-co-butylene fumarate) and Its Application as Polymeric Nucleating Agent for Poly(butylene succinate). Macromolecules 2012, 45, 5667-5675.
  6. Ye HM, Xu J*, Freudenthal J, Kahr B*. On the Circular Birefringence of Polycrystalline Polymers: Polylactide. J. Am. Chem. Soc., 2011, 133,13848–13851.
  7. Liu J, Ye HM, Xu J*, Guo BH. Formation of ring-banded spherulites of a and b modifications in poly(butylene adipate). Polymer 2011, 52, 4619-4630.
  8. Ye HM, Wang JS, Tang S, Xu J*, Feng XQ*, et al. Surface Stress Effects on the Bending Direction and Twisting Chirality of Lamellar Crystals of Chiral Polymer. Macromolecules 2010, 43, 5762–5770.
  9. Ye HM, Xu J*, Guo BH, Iwata T. Left- or Right-Handed Lamellar Twists in Poly[(R)-3-hydroxyvalerate] Banded Spherulite: Dependence on Growth Axis. Macromolecules 2009, 42, 694-701. (Cover article)
  10. Xu J, Guo BH, Zhang ZM, Zhou JJ, Jiang Y, Yan SK, Li L, Wu Q, Chen GQ, Schultz JM. Direct AFM Observation of Crystal Twisting and Organization in Banded Spherulites of Chiral Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate). Macromolecules 2004, 37, 4118-4123.