Description
The thesis presents an original and smart way to manipulate liquid and polymeric materials using a “pyro-fluidic platform” which exploits the pyro-electric effect activated onto a ferroelectric crystal. It describes a great variety of functionalities of the pyro-electrohydrodynamic platform, such as droplet self-assembling and dispensing, for manipulating multiphase liquids at the micro- and nanoscale. The thesis demonstrates the feasibility of non-contact self-assembling of liquids in plane (1D) using a micro engineered crystal, improving the dispensing capability and the smart transfer of material between two different planes (2D) and controlling and fabricating three-dimensional structures (3D). The thesis present the fabrication of highly integrated and automated ‘lab-on-a-chip’ systems based on microfluidics. The pyro-platform presented herein offers the great advantage of enabling the actuation of liquids in contact with a polar dielectric crystal through an electrode-less configuration. The simplicity and flexibility of the method for fabricating 3D polymer microstructures shows the great potential of the pyro-platform functionalities, exploitable in many fields, from optics to biosensing. In particular, this thesis reports the fabrication of optically active elements, such as nanodroplets, microlenses and microstructures, which have many potential applications in photonics. The capability for manipulating the samples of interest in a touch-less modality is very attractive for biological and chemical assays. Besides controlling cell growth and fate, smart micro-elements could deliver optical stimuli from and to cells monitoring their growth in real time, opening interesting perspectives for the realization of optically active scaffolds made of nanoengineered functional elements, thus paving the way to fascinating Optogenesis Studies. Introduction.- Chapter 1.- Wettability patterning by pyroelectric effect.- The pyro-electric effect onto a PPLN crystal.- Manipulation of polymer materials for patterning micro lenses.- Manipulating liquid crystal droplets onto polymer micro lenses.- Chapter 2.- Pyro-electrohydrodynamic dispenser.- Pyro-electrohydrodynamic dispenser: set-up.- Functionalities of the Pyro-Electrohydrodynamic dispenser.- Laser induced dispenser and visualization of the pyro-electric field line.- Laser induced dispenser activated by plasmon resonance of gold Nanorods.- Dispenser for liquid printing and patterning at high resolution.- Multi jets for the pyro-EHD dispenser.- Pyro-EHD process and instability of liquid film.- Polymer multi jetting.- Liquid delivering.- Fabrication of optical microlenses through the pyro-Dispenser.- Chapter 3.- Pyro-electrohydrodynamics (EHD) lithography for fabrication of polymer 3D microstructures.- Design and Working Principle of the Technique.- Experimental procedure of fabrication by pyro-EHD.- High aspect ratio micron-sized structures formation.- Applications of Rapid Cured PDMS Microstructures.- Chapter 4. Introduction to the high precision patterning of biomaterials.- Experimental set-up and pyro-electric spinning characterization.- Fabrication of well-ordered biocompatible and biodegradable patterns.- Cell contact guidance onto ordered fibers.- Chapter 5. Biodegradable microneedles for drug delivery applications.- Pyro-Electric fabrication of dissolving microneedles.- Skin indentation by PLGA electro-drawn microneedles.- Conclusions and perspectives.- Annex 1.- Annex 2.
