Phenolic Formaldehyde Resin-Based Nano-objects via a Modification-Induced Cooperative Assembly Process Using Poly(4-hydroxystyrene) as the Core-Forming Block

Harnessing the preparation and application of nano-objects with defined compositions and functions has much importance in advanced material fields. Although the scalable production of nano-objects has been accelerated by the efficient polymerization-induced self-assembly (PISA) process, more powerful self-assembly processes are still pursued. In this contribution, the modification-induced self-assembly (MISA) of poly(styrene)-b-poly(4-hydroxystyrene) (PS-b-PtBOS) diblock copolymers was studied by employing trifluoroacetic acid (TFA) as a modifying reagent and toluene as a selective solvent. Furthermore, to enrich the morphological formation window and enhance the MISA process, a modification-induced cooperative assembly (MICA) process was derived by synergistically incorporating the PS-b-PtBOS block copolymers and the PtBOS homopolymer into the same system. By comprehensively optimizing the degree of polymerization of PtBOS (DPPtBOS) and the PtBOS homopolymer content, the morphologies could be modulated in a broad window. Especially, the rarely observed sponge-like morphology was also captured in the MICA system. Additionally, employing the efficient reaction between the phenolic hydroxyl group and formaldehyde, the PHOS core can be stabilized and a phenolic formaldehyde resin-based nano-object could be generated. The MISA or MICA processes greatly facilitated the preparation of nano-objects, which have potential as novel advanced materials.