This study investigated the macrophase and microphase transitions of blends comprising polystyrene-block-poly(ethylene oxide) (PS-b-PEO) and polystyrene-block-poly(acrylic acid) (PS-b-PAA). PEO and PAA molecules formed hydrogen bonds that enabled the two block copolymers to organize into a single microphase-separated morphology composed of two PS block chains in a common PS microdomain and PEO and PAA block chains in a coexisting PEO/PAA microdomain. Increasing temperature weakened the hydrogen-bonding interaction through the formation of PAA monomers and anhydride, causing the blends to macrophase separate into PS-b-PEO-rich and PS-b-PAA-rich phases. Further increasing the temperature weakened the repulsive interactions between both the PS and PEO segments and the PS and PAA segments, inducing order-to-disorder transitions in the PS-b-PEO-rich and PS-b-PAA-rich phases. However, the increasing repulsive interaction between the PEO and PAA segments with increasing temperature prevented the blends from forming an isotropic phase. The unique phase transformation of each block copolymer in the blend with an upper critical ordering transition (UCOT)-type interaction parameter, which caused the formation of a lower-critical-solution-temperature-type phase diagram, was attributed to the hydrogen-bonding interaction between PEO and PAA, which outweighed the UCOT behaviors of PS-b-PEO and PS-b-PAA and reversed the phase behaviors of their blends.

本研究调查了包含聚苯乙烯-嵌段-聚（环氧乙烷）（PS- b - PEO）和聚苯乙烯-嵌段-聚（丙烯酸）（PS- b - PAA）的共混物的宏观相和微相转变。PEO 和 PAA 分子形成氢键，使两种嵌段共聚物能够组织成单个微相分离形态，该形态由公共 PS 微域中的两条 PS 嵌段链和共存的 PEO/PAA 微域中的 PEO 和 PAA 嵌段链组成。温度升高通过 PAA 单体和酸酐的形成削弱了氢键相互作用，导致共混物宏观相分离为富含 PS- b -PEO 和 PS- b-PAA 丰富的阶段。进一步升高温度削弱了 PS 和 PEO 链段以及 PS 和 PAA 链段之间的排斥相互作用，从而在富含 PS-b-PEO 和富含 PS- b - PAA 的相中诱导有序到无序的转变。然而，随着温度的升高，PEO 和 PAA 链段之间增加的排斥相互作用阻止了共混物形成各向同性相。共混物中每种嵌段共聚物的独特相变具有上临界有序转变 (UCOT) 型相互作用参数，导致形成下临界溶液温度型相图，这归因于氢键PEO 和 PAA 之间的相互作用，这超过了 PS- b -PEO 和 PS-的 UCOT 行为b -PAA 并反转了它们混合物的相行为。