Speaker: Mukerrem 'Miko' Çakmak
Title: Field Assisted "Z" orientation of Nanophases to Produce Thickness Functionalized films For Flexible Electronics using a New Roll to Roll manufacturing Platform
Date/Time: May 23, 2019 / 13.40-14.30
Place: FENS 2019
Abstract: Electric, Magnetic, and Thermal gradient fields are three important methods used in Field Assisted Self Assembly (FASA) of polymer blends, block copolymers, liquid crystals and polymer nanocomposites. These assisted assembly techniques have been used in laboratory scale, but for potential applications such as flexible electronics7, membranes8, supercapacitors, fuel cells, photovoltaic’s etc. a large scale manufacturing platform is needed.
We introduce a novel roll to roll process developed in our laboratories to achieve "Z-direction" alignment of nanostructural units. A 40ft line was designed which uses a casting system to deposit desired thickness of liquid such as a monomer, polymer solution as well as melt up to 6" wide on a flexible substrate. The substrate is then carried to an electric field application zone which consists of temperature controlled opposing roll to roll electrodes. The electric field applied can be a DC, AC or a biased AC, hence using the various fields we can maximize the orientation by increasing the dielectric contrast between the particles and the matrix.
If orientation and self-assembly through magnetic field is desired, the second tool located downstream is activated. This electromagnet is capable of applying magnetic fields up to 2.2 T to the material supported by a flexible substrate through the opposing poles. This line also contains a movable UV lamp which can be used to freeze the structure of required morphology using photocurable resin after electric field or magnetic field application zones.
Electric and magnetic field alignment of particles and polymer chains is studied through real time birefringence measurement, to determine various parameters effecting the orientation of particles/phases inside a polymeric film under the magnetic or electric field. The birefringence system is based on the solution drying process developed in our lab9.
In this talk, we will review our recent results on the use of this machine to produce Z-( thickness direction) functional films for capacitors, piezoelectric sensors, nanogenerators and transparent audio speakers, and piezoresistive films.
Bio: Prof. Mukerrem Cakmak is Reilly Professor of Materials and Mechanical Engineering at Purdue University has 34 years of academic experience in Polymer Processing field He is actively developing novel processes to address the needs of emerging markets. Towards this goal, his group recently developed a hybrid electrospinning/solution casting multipurpose processing platform to produce functional polymer films including conductive transparent films. More recent R2R machine developed applies electric, magnetic and thermal fields to orient particles and phases in the “Z” direction (normal to the film plane) to preferentially enhance through thickness conductivity, dielectric constant of films for flexible electronics.
Contact: Emre Erdem