THIN-FILM Composites

1. Polymer-Graphene Thin-Film Composites

Nanoscale thick, freely suspended electromechanical membranes are central to a wide range of technologies spanning from acoustic wave generators and receivers, to nanoelectromechanical systems (NEMS), and water purification devices. The use of ultrathin, lightweight materials in electromechanical membranes significantly reduces energy consumption and increases mechanical and electrical energy efficiency. Atomically thin graphene is promising for use in lightweight membranes because of its low weight, high electrical conductivity, and high mechanical strength. Known as the strongest 2D material, graphene can produce high sound pressure levels (SPL) via electromechanical actuation, making it advantageous for acoustic applications.  Nevertheless, single-layer graphene (SLG) does not survive free suspension over large areas because of defective carbon-carbon bonds, mostly at grain boundaries with lower stress thresholds for fatigue and fracture.

In our  lab, a lightweight, flexible, transparent, and conductive bilayer composite of polyetherimide and single-layer graphene is prepared and suspended on the centimeter scale with an unprecedentedly high aspect-ratio of 105. The coupling of the two components leads to mutual reinforcement and creates an ultra-strong membrane that supports 30,000 times its own weight. Upon electromechanical actuation, the membrane pushes a massive amount of air and generates high-quality acoustic sound. The energy efficiency is ~10-100 times better than state-of-the-art electrodynamic speakers. The bilayer membrane’s combined properties of electrical conductivity, mechanical strength, optical transparency, thermal stability, and chemical resistance will promote applications in electronics, mechanics, and optics.

Advanced Materials, 2020, 2004053

Patented.

2. Polymer-Plasmonic Nanoparticle Nanocomposites

Plasmonic nanoparticles have great potential in a wide range of applications including sensing, catalysis, imaging, medical diagnostics, and therapeutics. We specialize in synthesis of nanoparticles of various shapes, sizes, and compositions. The nanoparticles exhibit exciting optical and plasmonic properties. 

In our lab, we specialize in the synthesis of plasmonic nanoparticles, with the focus on their application in polymer nanocomposites. We aim to understand the polymer-nanoparticle interface and to provide insight into the design of polymer composites for energy and environment related applications, for example, heat-reflecting tinted glass (see figure below), light-actuated devices, hybrid solar cells,  light absorbers, and chemical sensors.

 Journal of Physical Chemistry C, 2016,120(34), 19353–19364

Analytical Chemistry, 2017, 89 (14), 7541-7548

ACS  Nano, 2019, 13 (4), 4255–4266.

Patent: US Provisional 62/448,581