TY - GEN A1 - Yin, Huajie T1 - Probing the glass transition temperature of polymers of intrinsic microporosity (PIMs) by fast scanning calorimeter N2 - High performance polymers of intrinsic microporosity (PIMs) have emerged as novel materials with broad applications from gas separation to electronic devices. Sufficiently rigid, even contorted polymer chains show only limited molecular mobility, therefore undergo inefficient packing and give rise to intrinsic microporosity with pore size generally smaller than 1 nm and BET surface areas larger than 700 m2/g. Further performance optimization and long-term stability of devices incorporating PIMs rely on our understanding of structure-processing-property relationships and physical aging, in which glass transition plays a key role. Up to now no glass transition temperature (Tg) of PIMs could be detected with conventional thermal analysis techniques before degradation. Decoupling the time scales responsible for the glass transition and the thermal decomposition is a reliable strategy to overcome this. This was achieved by employing fast scanning calorimetry (FSC) based on a chip sensor, which is capable to heat and cool a small sample (ng-range) with ultrafast rates of several ten thousand K/s. FSC provides definitive evidence of glass transition of a series of PIMs with a special consideration on the chain rigidity. The determined glass transition temperature of these PIMs follows the order of the rigidity of their backbone structures. FSC provides the first clear-cut experimental evidence of the glass transition of PIM-EA-TB with a Tg of 663 K, PIM-1 of 644 K and PIM-DMDPH-TB of 630 K at a heating rate of 1Χ104 K/s. Local fluctuations are featured in glass transition of highly rigid PIMs. As conformational changes are prevented by the backbone rigidity, the glass transition must rather be assigned to local small scale fluctuations. T2 - American Chemical Society (ACS) National Meeting & Expo 2019 CY - Orlando, FL, USA DA - 31.03.2019 KW - Glass transition KW - Polymers of intrinsic microporosity KW - Fast scanning calorimeter PY - 2019 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/47806 AN - OPUS4-47806 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany