10 Full Paper Macromol. Chem. Phys. 2012, 213, 10−18 © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim wileyonlinelibrary.com Macromolecular Chemistry and Physics DOI: 10.1002/macp.201100507 Tunable Morphologies From Bulk Self-Assemblies of Poly(acryloxypropyl triethoxysilane)- b -poly- (styrene)- b -poly(acryloxypropyl triethoxysilane) Triblock Copolymers Cé Guinto Gamys, Emmanuel Beyou,* Elodie Bourgeat-Lami, Laurent David, Pierre Alcouffe Reactive poly(acryloxypropyl triethoxysilane)- b-poly(styrene)- b-poly(acryloxypropyl triethoxysilane) (PAPTES- b-PS- b-PAPTES) triblock copolymers are prepared through nitroxide-mediated polymerization (NMP). The bulk morphologies formed by this class of copolymers cast into films are examined by small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). The films morphology can be tuned from spherical struc- tures to lamellar structures by increasing the volume fraction of PS in the copolymer. Thermal annealing at temperatures above 100 °C provides sufficient PS mobility to improve ordering. Self-assembled morphologies of traditional diblock copolymers are of four types: lamellar, spherical, bicon- tinuous and cylindrical. [11] Several additional phases are observed experimentally but are not thermodynamically stable. [2] The ultimate morphology is determined by the degree of polymerization and the relative composition of the different blocks. Besides, the phase behaviour of block copolymers in solution is different from that in the melt due to solvent–monomer and monomer–monomer inter- actions. Quite surprisingly, most of the works in this topic focus on diblock copolymers although it is well known that triblock terpolymers form a larger variety of well- ordered microdomain structures. [12] For instance, it has been found that ABA (or BAB) triblock copolymers display lower conformational entropy of its ordered state than that of an AB diblock copolymer with the same chain length and composition because the two block junctions are located at a domain boundary. [13] As a consequence, the disordered state of a triblock copolymer melt is more stable than that of a diblock copolymer. Controlled radical polymerizations, such as nitroxide mediated polymerization (NMP), atom transfer radical polymerization (ATRP) and reversible addition–frag- mentation chain transfer (RAFT), have enabled a vast array of block copolymers to be synthesized with great control over their chemical composition and molecular C. G. Gamys, E. Beyou, L. David, P. Alcouffe Ingénierie des Matériaux Polymères: CNRS UMR5223, Université de Lyon, Université Lyon 1, 15 boulevard Latarget, 69622 Villeurbanne, France E-mail: emmanuel.beyou@univ-lyon1.fr E. Bourgeat-Lami Laboratoire de Chimie, Catalyse, Polymères et Procédés (C2P2), LCPP group, CNRS, UMR 5265, 43, Bd. du 11 Novembre 1918, 69616 Villeurbanne, France 1. Introduction Self-organization can be defined as the spontaneous formation of a globally coherent pattern out of local interactions. Because self-organization is governed by an interplay between weak forces, it is a powerful approach to form mesostructured materials. In recent years, the formation of self-assembled structures from block copolymers have generated a significant interest because the latter offer a wide range of possibilities in terms of architecture, size and chemical composition, and allow achieving long-range ordering through micro- phase separation when the different bocks are chemi- cally immiscible. [1–10] The formation of ordered domains is driven by a balance between entropic and enthalpic forces and chemical bond constraints between the blocks.