A novel nanocomposite with gas sensing properties obtained through high-pressure synthesis

Polyphenylacetylene (PPhA) is a π-conjugated system, which has potential applications in organic electronics as a conductive polymer. Polymerization under pressure in confined systems such as zeolites can be used to select a particular isomer with its associated physical properties. In the present study, phenylacetylene (PhA) was polymerized in the 12 Å channels of the large-pore aluminosphoshate VFI under high pressure (HP), high temperature (HT) conditions of about 0.8 GPa and 140 °C, with relatively large volumes of 0.58 cm3. The material was first studied in-situ during its synthesis in diamond anvil cells (DAC) at the Xpress beamline and, guided by the in-situ results, optimized large volume samples (< 1 cm-3) were prepared in a HP bomb for the ex-situ analysis. The resulting polymer guest/insulating host composite was investigated by synchrotron X-ray diffraction (XRD) at the Xpress beamline of Elettra, (see Fig. 1-a) and infrared (IR) spectroscopy, both in-situ and ex-situ and by 1H, Raman and 13C and 27Al solid state Nuclear Magnetic Resonance (NMR) spectroscopies.  
HP insertion and pore filling were followed in-situ by synchrotron XRD by using a DAC at Xpress. Large volume samples were prepared for NMR analysis and were first characterized by synchrotron XRD (Fig. 1-a). The material consisting of disordered π-conjugated polyphenylacetylene chains in the pores of VFI, were deposited on quartz crystal microbalances and tested as gas sensors (Fig. 1-b). We obtained promising sensing performances to water and butanol vapors, attributed to the finely tuned nanostructure of the composites. 
In a more general framework, these results represent an important milestone in demonstrating the flexibility and effectiveness of high-pressure technology to provide a concrete response to technological requirements. Indeed, the improvement of gas-sensing performance with decreasing the diameter of the elementary nanostructures is well documented in literature, but our achievement, about the realization of gas sensors exploiting polymeric chains in the form of molecular wires, i.e. chains featuring the diameter of a single or a very few molecules, was a challenge. These results open the prospective for the realization ad exploitation of polymeric wires with diameter reduced at the extreme size of the single molecule in gas sensing.

Figure 1.  (a) Unit cell (outlined in black) and crystal structure of the VFI-PPhA composite obtained by Rietveld refinement. Observed and calculated powder XRD pattern collected ex-situ from the large volume nanocomposite sample recovered after compression of preloaded VFI in liquid PhA at 0.6 GPa and 130°C for 45 min (λ= 0.4957 Å). The light-blue and purple polyhedra are the AlO4, AlO6and PO4units of VFI while the black circles in the pore indicate C atoms from the inserted polymer. (b) polar plots of the responses measured with sensors based on pristine QCM (QCM0), QCM functionalized with VFI powders (VFI, pristine sample) and QCM functionalized with VFI-PPhA powders (VFI-PPhA) exposed to different vapours: sensor response expressed as frequency shift normalized to the shift measured with acetone.



This research was conducted by the following research team:

F. G. Alabarse1, M. Polisi2, M. Fabbiani3, S. Quartieri2, R. Arletti4, B. Joseph1, F. Capitani5, S. Contreras6, L. Konczewicz6, J. Rouquette7, B. Alonso7, F. Di Renzo7, G. Zambotti8, M. Baù8, M. Ferrari8, V. Ferrari8, A. Ponzoni8, M. Santoro9, J. Haines7



1 Elettra Sincrotrone Trieste SCpA, Trieste, Italy

2 Dipartimento di Scienze Chimiche e Geologiche, Università di Modena, Modena, Italy

3 Dipartimento di Chimica, Università di Torino, Italy

4 Dipartimento di Scienze della Terra, Università di Torino, Torino, Italy

Synchrotron Soleil, Saint Aubin – BP48, Gif sur Yvette, France

6 Laboratoire Charles Coulomb, CNRS, Université de Montpellier, Montpellier, France

7 ICGM, CNRS, Université de Montpellier, ENSCM, Montpellier, France

8 Istituto Nazionale di Ottica, INO-CNR, and Dipartimento di Ingegneria dell’Informazione, Università degli Studi di Brescia, Brescia, Italy

9 Istituto Nazionale di Ottica, INO-CNR, and European Laboratory for Non Linear Spectroscopy, LENS, Sesto Fiorentino, Italy

Contact persons:


Frederico Alabarse, email: 



F. G. Alabarse, M. Polisi, M. Fabbiani, S. Quatieri, R. Arletti, B. Joseph, F. Capitani, S. Contreras, L. Konczewicz, J. Rouquette, B. Alonso, F. Di Renzo, G. Zambotti, M. Baù, M. Ferrari, V. Ferrari, A. Ponzoni, M. Santoro, J. Haines, “High Pressure Synthesis and Gas Sensing Tests of 1-D Polymer/Zeolite Nanocomposites”. ACS Applied Materials & Interfaces13, 27237 (2021), https://doi.org/10.1021/acsami.1c00625

Last Updated on Tuesday, 27 July 2021 16:49