| 학회 | 한국고분자학회 |
| 학술대회 | 2005년 봄 (04/14 ~ 04/15, 전경련회관) |
| 권호 | 30권 1호, p.642 |
| 발표분야 | 기능성 고분자 |
| 제목 | Synthesis of Highly Soluble Conducting Polymers in Supercritical Carbon Dioxide |
| 초록 | Summary We report the synthesis of highly soluble conducting polythiophene esters, substituted with perfluoro and semifluoro alkyl groups in supercritical carbon dioxide (scCO2). Two kinds of 3 – fluoroalkyl ester substituted thiophene were prepared, and from which the polymers were synthesized by chemical oxidative polymerization with Iron (III) chloride in scCO2 at 3000 psi and 40 ° C. Polymers were obtained with good yield and characterized by NMR, GPC, and the extent of conjugation was determined by UV-Vis spectroscopy. Apart from the increase in the molecular weight due to the solubility of these polymers in scCO2, it is found that nearly insoluble FeCl3 could effectively oxidize thiophene compounds to produce the polymers. Introduction Conducting polymers and supercritical fluids have attracted considerable attention in recent years due to their excellent application in different areas. While scCO2 is essentially a ‘green’ solvent and environmentally benign, rapidly becoming a viable alternative solvent for various polymer synthesis and materials processing, conducting polymers are an attractive class of materials due to their potential applications as electronic materials and devices. A number of groups had reported the oxidative polymerization of thiophene and pyrrole and their conducting composite preparation with polystyrene and polyurethane in scCO2. However none of these polymers are soluble and all were carried out on heterogeneous polymerizations in scCO2. Given the fluorophilicty of scCO2, we designed soluble conducting polymers and synthesized these polymers in scCO2. We have shown that two different types of polythiophene ester derivatives, substituted with semi and perfluoro alkyl groups, synthesized by scCO2, exhibit high solubility at moderately low pressure and temperature. Experimental Synthesis scheme for monomers and polymers are shown in scheme 1 and 2. Two types of esters were synthesized by simple esterification of acid chlorides with corresponding alcohols. Polymerization was carried out at in scCO2 with ferric chloride as an oxidant at 3000-psi pressure and 40 ° C. Results &Discussion Conducting polymer synthesis by heterogeneous polymerization in scCO2 has been carried out typically with ferric triflate as an oxidant. However this oxidant is acidic in nature and corrosive acid like trifluoromethane sulphonic acid is necessary to prepare the oxidant. Though FeCl3 solubility is much lower in scCO2 than ferric triflate, we found that it also effectively oxidizes thiophene compounds to give the polymers. After 7 hrs of polymerizations, yields were found to be up to 60 %. The molecular weight was determined by GPC as 67 000 g/mol for PFTE. While PSFTE found to be soluble up to 1.66 wt % at 275 bar and 40 °C in CO2, PFTE was found be 0.104 wt %. This less solubility of PFTE is possibly due to a lower content of fluorine atoms in the side chain compared with PSFTE. We are also trying to explore the possibilities to produce these soluble polymers in nano-structured conducting particles by RESS supercritical process. |
| 저자 | Ganapathy Hullathy Subban, 황하수, 임권택 |
| 소속 | 부경대 |
| 키워드 | conducting polymer; polythiophene; carbon dioxide |
