The flexibility of LIFT technique enables the fabrication of chemical sensor arrays by depositing chemically sensitive polymer layers on ultrathin silicon membranes. LIFT is a direct technique offering high spatial resolution printing of a wide range of polymers and in this work it has been applied in the fabrication of a capacitive chemical sensor array with the ability to host up to 256 sensing sites. Each sensor in the array is composed of a Si membrane covered by a thin low temperature oxide layer and a polymer layer. Owing to the large number of sensing sites there is room for both sensitive polymer layer diversity as well as multiplicity, therefore expanding the capability for odour recognition.
Laser printing of polymer and polymer/nanocomposite materials
The incorporation of CNT into non-conductive polymer matrices can form conductive polymer composites, which are being used as new sensing materials for biosensors and chemical sensors. One of the most important challenges for the fabrication of these sensing devices is the deposition of the polymer/CNT composites onto the sensing elements. In particular, the fabrication of microsensors demands accurate deposition and/or pattering of polymer/CNT composite layers with submicron resolution. Since the common microelectronic techniques, such as photolithography, are difficult to implement on these complex materials, LIFT is an excellent alternative technique for direct and high spatial resolution dry and liquid printing of polymer/CNT composite patterns. LIFT is employed in a two-step process: the preparation of the target material and the selective deposition of a region of the target material through laser irradiation. The technique is applicable to a wide range of polymer/CNT composites, which may form uniform targets by spin coating or drop casting, regardless of the polymer and CNT concentration.
People
We implement Laser Induced Forward Transfer (LIFT) of polyaniline films for microbiosensor applications. Polyaniline films are printed in the solid phase by Laser Induced Forward Transfer directly in between aluminum electrodes lying on a glass substrate. To apply solid-phase laser printing, aniline is in situ polymerized on quartz substrates. The electrical characteristics of printed polyaniline present ohmic behavior, allowing for the use of these substrates in electrochemical biosensing applications.