Highly Stretchable Conducting SIBS‐P3HT Fibers

Abstract

Poly(styrene-β -isobutylene-β -styrene)-poly(3-hexylthiophene) (SIBS-P3HT) conducting composite fi bers are successfully produced using a continuous fl ow approach. Composite fi bers are stiffer than SIBS fi bers and able to withstand strains of up 975% before breaking. These composite fi bers exhibit interesting reversible mechanical and electrical characteristics, which are applied to demonstrate their strain gauging capabilities. This will facilitate their potential applications in strain sensing or elastic electrodes. Here, the fabrication and characterization of highly stretchable electrically conducting SIBS-P3HT fi bers using a solvent/non-solvent wet-spinning technique is reported. This fabrication method combines the processability of conducting SIBS-P3HT blends with wet-spinning, resulting in fi bers that could be easily spun up to several meters long. The resulting composite fi ber materials exhibit an increased stiffness (higher Young's modulus) but lower ductility compared to SIBS fi bers. The fi bers' reversible mechanical and electrical characteristics are applied to demonstrate their strain gauging capabilities. similar. The solubility parameter for toluene is 18.2 MPa ½ , [ 31 ] which is similar to the estimated value for SIBSs, which is 16.5 MPa ½ . The latter was calculated using the SIBS styrene/isobutylene ratio and the solubility parameters of styrene (17.8 MPa ½ ) and isobutylene (16.0 MPa ½ ). [ 31 ] The reported values of the P3HT solubility parameter range from 18.0 to 22.0 MPa ½ . [ 32 ] The solubility parameter of methanol is 29.7 MPa ½ [ 31 ] and it was used as the non-solvent. Solubility studies were used to confirm the suitability of our solvent/non-solvent system. SIBS fi bers ( Figure 1 ) were straightforward to spin and characterize, but we were unable to determine the electrical and mechanical properties for fi bers consisting entirely of P3HT. Although P3HT in its reduced form could be spun into fi bers, they were too brittle to handle without breaking. It was not possible to spin fi bers using P3HT in its oxidized form. DOIThree types of composite fi bers were prepared using spinning solutions consisting of SIBS combined with: i) P3HT oxidized with I 2 and doped with I 3 − , ii) P3HT doped with BF 4 − from tetrabutylammonium tetrafl uoroborate (TBABF 4 ) and oxidized with I 2 , and iii) P3HT doped with BF 4 − from tetrafl uoroboric acid (HBF 4 ) and oxidized with I 2 , which are hereafter referred to as PCP1, PCP2, and PCP3, respectively. The composition of these fi bers ( Table 1 ) was determined by elemental analysis. PCP2 and PCP3 fi bers were prepared using P3HT-doped with BF 4 − , from different molecules (TBABF 4 and HBF 4 ). This affected the resulting P3HT loading in the composite fi ber. For example, PCP2 fi bers spun with a 1.4% (w/v) P3HT concentration yield a 1:0.11 SIBS:P3HT ratio in the resulting fi ber. Using the same concentration in the preparation of PCP3 fi bers results in a 1:0.14 SIBS:P3HT ratio. The optical transparency and surface morphology of P3HT-co...

Strain‐Responsive Polyurethane/PEDOT:PSS Elastomeric Composite Fibers with High Electrical Conductivity

“…[ 30 ] To the best of authors' knowledge, the value of σ 0 (166.0 S cm −1 ) obtained in this study is the highest value for elastomeric conducting composites and among the highest value reported in the literature with only polystyrene/graphene composite showing a higher value (831.8 S cm −1 ). [ 64 ] …”

“…Fiber spinning was carried out using the previously described wet-spinning setup for PEDOT:PSS fi bers [ 8 ] and SIBS/P3HT fi bers. [ 30 ] Briefl y, the spinning solution was injected into the coagulation bath containing the non-solvents (i.e., water, isopropanol, or isopropanol/water mixture). A 23 gauge needle with blunt tip was used as a spinneret.…”

“…The lack of progress in this fi eld can be attributed to the limited development of elastomeric composite formulations that contain welldispersed conducting fi llers, which are also processable by fi ber wet-spinning methods. In the limited cases where conductive fi llers such as polyaniline, [ 29 ] polythiophene [ 30 ] and carbon nanotubes [ 31 ] were utilized in the wet-spinning of conducting fi ber composites, the observed change in the electrical properties have only been marginal at large deformations. These reports also show that signifi cant amount of fi ller loading is necessary to achieve percolation of conducting networks, which was found to be detrimental to the overall mechanical properties of the composite.…”

Structure and design of polymers for durable, stretchable organic electronics

“…Poly(styrene-isobutylene-stryrene)/P3HT 2b fibers have been studied to create a material with a competitive combination of mechanical strain and conductivity. 167 At maximum strain, the resistance of these fibers after 20 cycles changed only 3%. It is suspected that resistance decreases after the 'threshold strain' because the isobutylene block of poly(styrene-isobutylene-stryrene) undergoes strain-crystallization increasing contact between domains, increasing conductivity.…”

Characterisation of graphene fibres and graphene coated fibres using capacitively coupled contactless conductivity detector

“…6 The availability and liquid crystalline properties of the graphene oxide (GO) sheets, 7,8 together with the use of wet-spinning technology 9 has accelerated the progression of the manufacture of ultra-strong and electrically conducting GBFs. 5,[10][11][12][13][14][15] However, wet-spinning has some limitations in performance and requires precise control of formulation in the spinning dope dispersions, conditions within the coagulation bath, with each step affecting final fibre morphology. Although the cost of processing GBFs is much lower than those of other carbon fibres, including carbon nanotube (CNT) containing fibres, the strength and electrical properties are poorer.…”