Prof. Dr. Axel Müller

Double-grafted cylindrical brushes with poly(lauryl methacrylate) (PLMA) as the side chains were synthesized using the grafting-from strategy via atom transfer radical polymerization (ATRP). The polyinitiator poly[2-(2-bromoisobutyryloxy)ethyl methacrylate] (PBIEM) with DP_n = 240 and 1 500 served as the backbone. The PLMA side chains of the brushes carry long alkyl chains. GPC and ¹H NMR measurements confirmed the successful formation of the PLMA cylindrical brushes. The side chains were cleaved from the cylindrical brushes by transesterification. GPC and ¹H NMR results indicate that the initiating efficiency of the bromoester groups on the backbone for the bulky monomer was in the range of 0.34≤f≤0.67. Static and dynamic light scattering show that the ratio of the radius of gyration to the hydrodynamic radius, R_g/R_h, is in the range of 1.2–1.3, indicating that the LMA cylindrical brushes are semiflexible in solution. Atomic force microscopy (AFM) measurements show that short PLMA brushes exhibit a spherical morphology while the long brushes exhibit a worm-like structure. DSC displayed melting peaks at around –30 °C, indicating the alkyl side chains of the PLMA chains in the double-grafted cylindrical brushes are crystallizable.