Hongwei Liu

Institution:
Naples University, Italy
Supervisors:
Giovanni Ianniruberto

 

Field of expertise:
Modeling Polymer Rheology
PhD subject:
Modeling the Nonlinear Rheology of Reversible Double Dynamics Networks

The existence of the reversible noncovalent bonds (the green stickers shown in Fig. 1), such as hydrogen bonds, - stacking, metal-ligand and ionic interactions
in the polymers makes it possible to form transient networks. On the other hand, the presence of covalent bonds (the red stickers shown in Fig. 1) can lead to the
formulation of permanent networks. While the transient networks are reversible, easily processable and recyclable, the permanent networks are able to resist flow
and creep, and to swell without losing their coherence. The co-existence of these two kinds of networks in polymers makes them ideal for applications, such as high
mechanical strength, large reversible deformability in shear and extension, substantial reversible swelling, and self-healing properties. We are aiming at unveiling the
mechanisms behind these unique properties by modeling so that they can be fully exploited.

Since Rubinstein et al. firstly proposed the sticky Rouse model, many improvements have been done to this model. However, most of the models are single chain
model and it has inborn shortcomings. For one thing, single chain model can not predict the structure of associating polymers. For another, in single chain model
system, the interactions between different chains are simulated through virtual (not real) coupling. Differently, we adopt multi-chain sticky Rouse model to simulate
the associating polymers. Additionally, periodic boundary conditions are utilized, which allows us to simulate the macroscopic phenomena from the mesoscopic scale (Fig. 2).

The expected accomplishments are: simulating multiple dynamics in reversible DDNs, modelling the nonlinear viscoelastic properties of sticky DDNs, study the influence of chain stretching on the lifetime of reversible properties and relating chain stretching and strain hardening to adhesive properties.

Fig.1: Single networks with dual crosslinks.

Language
  • Chinese Speaking
  • English Speaking
Awards
  • 2017-2018, Outstanding students of Guangdong province
  • 2016-2017, National Scholarship for Graduate Students
  • 2014-2015, The Graduation Project was rated as Excellent
  • 2013-2014, The Third Prize Scholarship & Merit Student
  • 2012-2013, The Third Prize Scholarship
Publications
  • Hongwei Liu and Jiong Wang and Hui-Hui Dai, 2017. Analytical study on stress-induced phase transitions in geometrically graded shape memory alloy layers. Part I: Asymptotic equation and analytical solutions. Mechanics of Materials. 112, 40-55. IF=2.651.
  • Hongwei Liu and Jiong Wang and Hui-Hui Dai, 2017. Analytical study on stress-induced phase transitions in geometrically graded shape memory alloy layers. Part II: Analyses on geometrical shapes, loading procedures and boundary conditions. Mechanics of Materials. 112, 114–128. IF=2.651.

Curriculum Vitae

CV Hongwei Liu

Academic Activities

Contributed Speakers, International Conference on Applied Mathematics

June 4th – June 8th, 2018

CityU LBY, Hong Kong

 

Workshop Physically-Based Modeling of Polyatomic Gases and Phase
Transitions

Attending conference

July 4th – July 15th, 2016

OIST, Okinawa, Japan

Education

Università degli Studi di Napoli Federico II

Ph.D. Polymer Rheology

September 2018 - Current

 

South China University of Technology

M.S. Mechanics

September 2015 - June 2018

 

HeFei University of Technology

B.S. Engineering Mechanics

September 2011- July 2015

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