| 1. |
- Asplund, Maria, et al.
(författare)
-
Electroactive polymers for neural interfaces
- 2010
-
Ingår i: Polymer chemistry. - : Royal Society of Chemistry (RSC). - 1759-9954 .- 1759-9962. ; 1:9, s. 1374-1391
-
Forskningsöversikt (refereegranskat)abstract
- Development of electroactive conjugated polymers, for the purpose of recording and eliciting signals in the neural systems in humans, can be used to fashion the interfaces between the two signalling systems of electronics and neural systems. The design of desirable chemical, mechanical and electrical properties in the electroactive polymer electrodes, and the means of integration of these into biological systems, are here reviewed.
|
|
| 2. |
|
|
| 3. |
- Inganäs, Olle, et al.
(författare)
-
Conjugated polymer gels as 3-D electrodes.
- 2001
-
Ingår i: Abstracts of Papers of the American Chemical Society. - 0065-7727. ; 221, s. 429-IEC-
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
|
|
| 4. |
- Nyberg, Tobias, et al.
(författare)
-
Macromolecular nanoelectronics
- 2002
-
Ingår i: Current applied physics. - 1567-1739 .- 1878-1675. ; 2:1, s. 27-31
-
Tidskriftsartikel (refereegranskat)abstract
- We have explored new organic materials and fabrication methods to fabricate organic photodiodes and light emitting diodes. Grafting of a fullerene derivative to a polythiophene backbone yielded an integrated acceptor-donor polymer that we used as the active material in organic photodiodes. Using a method of soft lithography. soft embossing, we fabricated submicron structures to be used as organic light emitting diodes. Employing a silicone rubber replica (stamp) of an optical diffraction grating we transferred the grating pattern to an organic resist layer by placing the stamp in conformal contact with the resist. The transferred pattern was subsequently used as an etch mask for the processing of the device. The structures were successfully utilized as light emitting diodes and photodiodes, with device characteristics influenced by the imposed structure. (C) 2002 Published by Elsevier Science B.V.
|
|
| 5. |
- Nyberg, Tobias, et al.
(författare)
-
Polymer hydrogel microelectrodes for neural communication
- 2002
-
Ingår i: Biomedical microdevices (Print). - 1387-2176 .- 1572-8781. ; 4:1, s. 43-52
-
Tidskriftsartikel (refereegranskat)abstract
- A conducting polymer hydrogel electrode was electrochemically deposited in micromachined via holes and the charge delivery capacity (CDC) was studied. Polymer hydrogel microelectrodes, with a geometric area of 1000 mum(2), and a capacitance of up to 850 nF were fabricated. The impedance of a 1,000 mum(2) polymer hydrogel electrode deposited with 8 muC was measured as low as 8.5 kOmega. We studied neural cell growth on structures to be used as neural interfaces. Directed cell growth was achieved by imposing a topographical structure on the substrate. Due to the interesting mechanical and chemical adaptability of the polymer hydrogel material and its large charge delivery capacity and low impedance we think that it is an interesting material for neural communication.
|
|
| 6. |
- Nyberg, Tobias, et al.
(författare)
-
Submicrometre bridge electrode arrays for light emitting polymer diodes and photodiodes
- 2002
-
Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 13:2, s. 205-211
-
Tidskriftsartikel (refereegranskat)abstract
- We have used a method of soft lithography, soft imprinting, to fabricate submicrometre structures to be used as light emitting polymer diodes and photodiodes. Using a silicone rubber replica (stamp) of an optical diffraction grating we transferred the grating pattern to an organic resist layer by placing the stamp in conformal contact with the resist. The transferred pattern was subsequently used as an etch mask for the processing of the device. This cheap and fast process, not limited by optical diffraction, was used to fabricate submicrometre structures over large areas, square millimetres. The structures were successfully utilized as light emitting diodes and photodiodes, with device characteristics influenced by the imposed structure.
|
|
| 7. |
- Roman, LS, et al.
(författare)
-
Trapping light in polymer photodiodes with soft embossed gratings
- 2000
-
Ingår i: Advanced Materials. - 0935-9648 .- 1521-4095. ; 12:3, s. 189-
-
Tidskriftsartikel (refereegranskat)abstract
- Increasing the conversion efficiency is very important in photovoltaic devices, as is cheap and simple technology. Here is demonstrated a soft embossing technique for printing a submicrometer grating with an elastomeric mold into an optically active polymer layer in a photovoltaic device (see Figure). The light trapping due to the grating pattern enhances the photoconversion efficiency by more than 25 % at normal light incidence (see also inside front cover).
|
|
| 8. |
- Thaning, Elin M., et al.
(författare)
-
Stability of Poly(3,4-ethylene dioxythiophene) Materials Intended for Implants
- 2010
-
Ingår i: Journal of Biomedical Materials Research - Part B Applied Biomaterials. - : Wiley. - 1552-4973 .- 1552-4981. ; 93B:2, s. 407-415
-
Tidskriftsartikel (refereegranskat)abstract
- This study presents experiments designed to study the stability of the conducting polymer poly(3,4-ethylene dioxythiophene) (PEDOT), under simulated physiological conditions using phosphate-buffered saline (PBS) and hydrogen peroxide (H2O2) (0 01M) at 37 degrees C over a 5- to 6-week period Voltage pulsing in PBS was used as an additional test environment The influence of switching the counter ion used in electropolymerization from polystyrene sulphonate (PSS) to heparin was investigated Absorbance spectroscopy and cyclic voltammetry were used to evaluate the material properties Most of the samples in H2O2 lost both electroactivity and optical absorbance within the study period, but PEDOT.PSS was found slightly more stable than PEDOT heparin. Polymers were relatively stable in PBS throughout the study period, with around 80% of electroactivity remaining after 5 weeks, disregarding delamination, which was a significant problem especially for polymer on indium tin oxide substrates Voltage pulsing in PBS did not increase degradation. The counter ion influenced the time course of degradation in Oxidizing agents.
|
|
| 9. |
- Thaning, Elin, et al.
(författare)
-
Stability of PEDOT materials intended for implants
-
Annan publikation (populärvet., debatt m.m.)abstract
- This study presents a set of experiments designed to study the stability over time of the conducting polymer poly(3,4-ethylene dioxythiophene) (PEDOT), under simulated physiological conditions. Especially, the influence of switching the counter ion used in electropolymerisation, from surfactant polystyrene sulphonate (PSS) to heparin, was investigated. Electropolymerised PEDOT was exposed to different solutions at 37 °C over a 5-6 weeks study period. Two methods were used to study changes over time, spectroscopy and cyclic voltammetry. Phosphate buffer solution (PBS) and diluted hydrogen peroxide (H2O2) (0.01 M) were used to simulate in vivo environment. Some PEDOT electrodes in PBS were also subject to voltage pulsing to further stress the material. The vast part of the samples of both types lost both electroactivity and optical absorbance within the study period, when exposed to H2O2. An overall slightly higher stability of PEDOT:PSS compared to PEDOT:heparin could be seen. The time dependence of the decline also differed, with a linear decrease of electroactivity for PEDOT:heparin while for PEDOT:PSS a comparably stable appearance initially, followed by a marked decrease after 8-15 days. Polymers were relatively stable in PBS throughout the study period, with around 80% of electroactivity remaining after five weeks. Disregarding a slight drop in electroactivity during the first day, voltage pulsing in PBS did not increase degradation (tested over 11 days). Delamination of PEDOT exposed to PBS was however a significant problem, especially for polymer on ITO substrates. PEDOT is sensitive to oxidising agents, also in the dilute concentrations used here, and counter ion influences the time course of degradation. Even without oxidising agents, some decline in electroactivity can be expected and it is unclear whether this decrease will continue over time, or if the polymer will stabilise. Such stabilisation was however not seen within the five weeks studied here. Delamination of polymer is likely to be a problem on implantation, especially with unwisely chosen substrates, and might be an even more serious threat to long term applications than degradation in biological fluids.
|
|
| 10. |
- Zhang, Fengling, et al.
(författare)
-
Conducting Polymer Nanowires and Nanodots Made with Soft Lithography
- 2002
-
Ingår i: Nano letters (Print). - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 2:12, s. 1373-1377
-
Tidskriftsartikel (refereegranskat)abstract
- The conducting polymer poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate) (PEDOT-PSS) was patterned by micromolding in capillaries (MIMIC), in the form of nanowires on a glass or a Si wafer. The periods of the molded nanowires were 833 or 278 nm. By applying force on top of the stamp during MIMIC, the height of these nanowires could be changed. An alternative method of preparing structured surfaces is the liquid embossing technique, used to pattern polymers deposited from dispersion. Nanowires (278 nm) and 2-D nanodots on semiconducting polymer (poly(3-(2'-methoxy-5'-octyphenyl) thiophene)) POMeOPT were also achieved by another soft lithography technique-soft-embossing. The possibility to pattern both semiconducting and metallic conjugated polymers from aqueous solutions or organic solvents on a submicron level makes it possible to use these materials in flexible optoelectronic devices where light propagation and electronic paths are defined by patterning.
|
|
