Guilhermo J. M. Fechine

Position: Associate Professor

Area of interest: Composites

Email: guilherminojmf@mackenzie.br

Office: 101

Phone: + 55 (11) 2114 8077

 

He obtained the degree of Material Engineer in 1996 and MSc degree in 1998, both of them awarded by Federal University of Paraíba, Brazil. He obtained his PhD in Chemistry at Federal University of Pernambuco (Brazil) in 2001. The subjects of the MSc and PhD degrees talked about photodegradation and photostabilization of the different polymers. He had made two post-docs, both at University of São Paulo, Brazil. One of them on Chemistry Institute (2002 – 2005) and the main area was Hydrogels, and the other one was about Biodegradable blends and polymeric composites at Polytechnic School (2005-2008). Since May of 2008 he is a professor at Presbyterian Mackenzie University. He spent one year (2013) at National University of Singapore – NUS as a Visiting Professor and worked with methodologies of graphene transfer. Current topics covered in their research are related to the understanding of the interactions between polymers and 2D materials (graphene, MoS2, hBN, phosphorene, etc.), whether for improving transfer processes or polymer nanocomposites.

 

 

Polymer-2D Materials Interactions: Transfer processes and obtaining nanocomposites

 

 

The understanding of the phenomena that govern the interaction between two-dimensional materials and polymers is of utmost importance to understand the transfer processes as well as the production of polymer nanocomposites. Among these fields of activity, new graphene transfer processes and other two-dimensional materials have been proposed with a view to improving their quality. An example of the need for proper transfer process can be observed in the production of flexible touch-screens devices.

The possibility of the use of graphene for the production of these devices is connected on how to obtain graphene sheets with considerable dimensions, which are only possible by the CVD technique (Chemical Vapor Deposition). However, this graphene is obtained on a metal sheet and requires that it be transferred to a flexible substrate, a polymer, so that the device be constructed. This transfer process is challenging, because it handles a material with a thickness of one atom and any damage can be generated during the transfer. This control is done by the perfect adjust of 2D material-polymeric interface.

Nanocomposite materials are seeking to join properties of at least two different types of materials to obtain a superior material, and the fillers present are in nanometer scale. Good dispersion and a strong interaction of a two-dimensional material inserted in a polymer is the secret for attaining exceptional properties that the polymer alone does not have. Examples are lighter and more resilient materials for automotive, sporting goods, packaging, among others. In addition to improvements in mechanical properties, 2D fillers may also change other properties. In the case of graphene, this can transform an insulating material into a plastic material capable of conducting electricity.

Experimental and computational methods are used to calculate the interactions between polymer and two-dimensional materials. Figure 1 below shows images of a computer program used to calculate the force to keep a flat sheet of graphene and a mass of polymer chains together.

 

The perfect knowledge of the interactions between polymers and two-dimensional materials is the key to success for preparation and obtaining of materials with advanced technology.