Synthesis and properties of poly(3-n-dodecylthiophene) modified thermally expandable microspheres

Functionalization of thermally expandable microspheres (TEMs) with a conjugated polymer is explored. These functionalized thermally expandable microspheres were prepared by grafting 3-n-dodecylthiophene via oxidative polymerization from a thiophene modified TEM. The thiophene modified TEM to 3-n-dodecylthiophene ratio was varied during grafting and the resulting poly(3-n-dodecylthiophene) grafted TEM were characterized by FT-IR spectroscopy, Thermal Gravimetric Analysis, Scanning Electron Microscopy, Thermo-Mechanical Analysis and X-ray diffraction. The particles were approximately 30 μm in diameter and upon heating, the functionalized microspheres expanded up to 50 times. This expansion property was related to the poly(3-n-dodecylthiophene) content, where the increase in poly(3-n-dodecylthiophene) on microsphere decreased the thermal expansion. The X-ray diffraction shows a sharpening of the poly(3-n-dodecylthiophene) (1 0 0) diffraction peak upon expansion. Grafting conjugated polymers to thermally expandable microspheres provides robust functional photo- and electro-active TEMs.