Final Report Summary - ORITUPOCO (Orientation of Carbon Nanotubes in Polymer Composites)
A summary description of the project objectives:
The main objective of proposal is preparing new polymer composites with aligned carbon nanotubes (CNTs). Photo-active organic groups can be used to reach the aims. An interdisciplinary approach is needed for achieving major advances in this proposal ranging from:
a) Chemical functionalisation of CNTs
b) Composite processing
c) Photochemistry
d) Utilisation of measurements methods.
Thus, the proposal requires the knowledge of chemistry, materials science, nanoscience, mechanics and engineering. This can lead to establishing of new collaborations in these areas. It is expected the results of the project to be of fundamental importance to the field of nanotechnology, making a significant contribution to high-performance composite materials and nanoactuators.
A description of the work performed since the beginning of the project:
Department of composite materials from Polymer Institute was participant in FP7 Programme NMP-NOMS: Nano-Optical Mechanical Systems" covered novel developments in optically-actuated nano-composite materials. Therefore second part of ERG project (photochemistry of CNT polymer composites) was adjusted to NOMS project due closer collaboration with other departments of Polymer Institute.
The proposal planned to prepare carbon nanotube (CNT)/polymer composites. The polymer matrix was used Kraton D 1165PT-linear triblock copolymer based on styrene and isoprene with a polystyrene content of 30 % or the commercial ethylene vinyl acetate LEVAPREN500 copolymer containing 50 wt. % of vinyl acetate. Both of them are flexible at room temperature but very brittle at temperature below 270 K. This flexibility allows uniaxial stretching of composite and possible photoactuation at room temperature. The orientation of CNTs was reached by two ways:
-the first way, well-dispersed surface modified CNTs in elastic network was uniaxially stretched and then freezed to the oriented system.
-the second way, semi-oriented CNTs in stretched composite were illuminated with laser.
A description of the main results achieved so far:
-The orientation of CNTs in elastic polymer matrix was reached. During uniaxial stretching of composites was observed increasing conductivity in direction of stretching (decreasing perpendicular). This behaviour is an evidence of uniaxial orientation of CNTs inside matrix that was confirmed by Scanning Electron Microscopy. However CNT orientation continued till abruption of sample during tensile test, conductivity of oriented samples reached maximum point before break. At this point CNT orientation of percolated conductive network reached maximum orientation. Behind this point, orientation of CNT network continued, but conductive network was destroyed by elongation oriented CNTs increased distance between conductive contacts of CNTs and start to prevail insulating character of polymer matrix (the distance between individual contacts was too long for conductive transport). The elongation of CNT-polymer composites.
-The photo-actuation response was studied by Dynamic Mechanical Analysis (DMA) for unstretched strip based on Styrene-Isoprene-Styrene (SIS) composite containing CNTs. The photo-actuation response was monitored by DMA equipped by red diode (Luxeon Rebell, Philips, lambda = 627 nm) by Iso-Strain mode, preload was applied 0. 04 N and pre-strain 0. 05 %, 10 % and 15 %. The strip was placed between two clamps and irradiated by red diode at 300 mA (power 58 mW) for 10 or 30 seconds and the changes in stress over time were recorded simultaneously. The setup for photo-actuation measurement of an strip upon illumination using red light-emitted diode by Dynamical Mechanical Analyser. The obtained results for 0. 05 % applied pre-strain for the unstretched strip based on an SIS composite containing 0. 3 wt. % CNTs upon 10 second (10 cycles, left) and 30 second (10 cycles, right) illumination using a red light-emitted diode at an applied current of 300 mA (power 58 mW). During illumination of composites CNTs have ability to orient inside elastic matrix (photo-actuation) what is accompanied by change of stress inside sample. If the sample is pre-stessed (a small pre-orientation is reached) effect of photo-actuation is pronouced.
The expected final results and their potential impact and use:
-Mechanical orientation of CNT-polymer composites was reached by uniaxial stretching. Orientation of nanotubes has effect on conductivity of sample in direction of stretching. This conductivity can be adjusted by degree of stretching. The orientation structure can be fixed for longer time based on temperature or external mechanical device.
-CNTs in elastic polymer matrix can perform photo-actuation. A degree of actuation is significantly dependent on degree of pre-orientation of CNT s inside elastic polymer matrix.
-Preliminary results on composite melt showed that orientation of CNTs inside melt should be reached with high electric field (at level of kV).
-Preliminary results of photo-actuation showed CNTs should be replaced with cheaper carbon material graphene.
The socio-economic impact and the wider societal implications of the project so far:
The project was focused on REINTEGRATION. Applicant returned from two abroad Marie Curie post-doc study stays (Czech Republic and Greece) to home institution Polymer Institute Slovak Academy of Sciences. His knowledge from foreign institution was implemented in Polymer Institute. Skills with carbon nanotubes were used for other scientific work, preparation of buckypapers was implemented to preparation of sensors for other project (Lobotka P etal.: Thin Solid Films 2011, 519, 4123-4127). Immediately after his return, Dr. Spitalsky was included to collaboration with other departments (organic synthesis modification of CNTs), other institutions (projects APVV about CNT sensors with Institute of Electrical Engineering of Slovak Academy of Sciences) and international collaboration (bilateral projects with Czech Republic, Portugal, Serbia, China, and Quatar). His expertise from Greece allowed introduced new methodology to Polymer Institute Broadband dielectric spectroscopy. New methodology allowed to supervise him 2 new students whose will focus at dielectric/conductive properties of new materials during their diploma/PhD study.
Based on his experience from foreign scientific institution, he became member of some advisory boards at Polymer Institute
The main objective of proposal is preparing new polymer composites with aligned carbon nanotubes (CNTs). Photo-active organic groups can be used to reach the aims. An interdisciplinary approach is needed for achieving major advances in this proposal ranging from:
a) Chemical functionalisation of CNTs
b) Composite processing
c) Photochemistry
d) Utilisation of measurements methods.
Thus, the proposal requires the knowledge of chemistry, materials science, nanoscience, mechanics and engineering. This can lead to establishing of new collaborations in these areas. It is expected the results of the project to be of fundamental importance to the field of nanotechnology, making a significant contribution to high-performance composite materials and nanoactuators.
A description of the work performed since the beginning of the project:
Department of composite materials from Polymer Institute was participant in FP7 Programme NMP-NOMS: Nano-Optical Mechanical Systems" covered novel developments in optically-actuated nano-composite materials. Therefore second part of ERG project (photochemistry of CNT polymer composites) was adjusted to NOMS project due closer collaboration with other departments of Polymer Institute.
The proposal planned to prepare carbon nanotube (CNT)/polymer composites. The polymer matrix was used Kraton D 1165PT-linear triblock copolymer based on styrene and isoprene with a polystyrene content of 30 % or the commercial ethylene vinyl acetate LEVAPREN500 copolymer containing 50 wt. % of vinyl acetate. Both of them are flexible at room temperature but very brittle at temperature below 270 K. This flexibility allows uniaxial stretching of composite and possible photoactuation at room temperature. The orientation of CNTs was reached by two ways:
-the first way, well-dispersed surface modified CNTs in elastic network was uniaxially stretched and then freezed to the oriented system.
-the second way, semi-oriented CNTs in stretched composite were illuminated with laser.
A description of the main results achieved so far:
-The orientation of CNTs in elastic polymer matrix was reached. During uniaxial stretching of composites was observed increasing conductivity in direction of stretching (decreasing perpendicular). This behaviour is an evidence of uniaxial orientation of CNTs inside matrix that was confirmed by Scanning Electron Microscopy. However CNT orientation continued till abruption of sample during tensile test, conductivity of oriented samples reached maximum point before break. At this point CNT orientation of percolated conductive network reached maximum orientation. Behind this point, orientation of CNT network continued, but conductive network was destroyed by elongation oriented CNTs increased distance between conductive contacts of CNTs and start to prevail insulating character of polymer matrix (the distance between individual contacts was too long for conductive transport). The elongation of CNT-polymer composites.
-The photo-actuation response was studied by Dynamic Mechanical Analysis (DMA) for unstretched strip based on Styrene-Isoprene-Styrene (SIS) composite containing CNTs. The photo-actuation response was monitored by DMA equipped by red diode (Luxeon Rebell, Philips, lambda = 627 nm) by Iso-Strain mode, preload was applied 0. 04 N and pre-strain 0. 05 %, 10 % and 15 %. The strip was placed between two clamps and irradiated by red diode at 300 mA (power 58 mW) for 10 or 30 seconds and the changes in stress over time were recorded simultaneously. The setup for photo-actuation measurement of an strip upon illumination using red light-emitted diode by Dynamical Mechanical Analyser. The obtained results for 0. 05 % applied pre-strain for the unstretched strip based on an SIS composite containing 0. 3 wt. % CNTs upon 10 second (10 cycles, left) and 30 second (10 cycles, right) illumination using a red light-emitted diode at an applied current of 300 mA (power 58 mW). During illumination of composites CNTs have ability to orient inside elastic matrix (photo-actuation) what is accompanied by change of stress inside sample. If the sample is pre-stessed (a small pre-orientation is reached) effect of photo-actuation is pronouced.
The expected final results and their potential impact and use:
-Mechanical orientation of CNT-polymer composites was reached by uniaxial stretching. Orientation of nanotubes has effect on conductivity of sample in direction of stretching. This conductivity can be adjusted by degree of stretching. The orientation structure can be fixed for longer time based on temperature or external mechanical device.
-CNTs in elastic polymer matrix can perform photo-actuation. A degree of actuation is significantly dependent on degree of pre-orientation of CNT s inside elastic polymer matrix.
-Preliminary results on composite melt showed that orientation of CNTs inside melt should be reached with high electric field (at level of kV).
-Preliminary results of photo-actuation showed CNTs should be replaced with cheaper carbon material graphene.
The socio-economic impact and the wider societal implications of the project so far:
The project was focused on REINTEGRATION. Applicant returned from two abroad Marie Curie post-doc study stays (Czech Republic and Greece) to home institution Polymer Institute Slovak Academy of Sciences. His knowledge from foreign institution was implemented in Polymer Institute. Skills with carbon nanotubes were used for other scientific work, preparation of buckypapers was implemented to preparation of sensors for other project (Lobotka P etal.: Thin Solid Films 2011, 519, 4123-4127). Immediately after his return, Dr. Spitalsky was included to collaboration with other departments (organic synthesis modification of CNTs), other institutions (projects APVV about CNT sensors with Institute of Electrical Engineering of Slovak Academy of Sciences) and international collaboration (bilateral projects with Czech Republic, Portugal, Serbia, China, and Quatar). His expertise from Greece allowed introduced new methodology to Polymer Institute Broadband dielectric spectroscopy. New methodology allowed to supervise him 2 new students whose will focus at dielectric/conductive properties of new materials during their diploma/PhD study.
Based on his experience from foreign scientific institution, he became member of some advisory boards at Polymer Institute