Liquid crystalline ordering in planar polymer brushes is investigated theoretically by numerical calculations within a self‐consistent field approximation. The brushes are formed by macromolecules with mesogenic groups in main chain and immersed in a solvent. Existence of a microphase segregated brush (MSB) regime with a collapsed orientationally ordered intrinsic sublayer and a swollen external sublayer is shown. At small grafting density, the transition from a conventional brush state to the microphase segregated state is a jump‐wise first order phase transition for a finite chain length (N). The magnitudes of the jumps in the average characteristics of the brush tend to zero in the limit N → ∞ since this transition occurs only in a vanishingly small part (∝ N−1/2) of the brush. High compressibility of MSB brush is demonstrated. The origin of phase transition in planar brushes is discussed.

Polymer bio-nanocomposites are widely used nowadays in various applications. One of the most promising polymers for producing such materials is poly(lactic acid) (PLA) filled with cellulose nanocrystals (CNCs). To increase the compatibility of hydrophobic PLA and hydrophilic cellulose, the surface of the latter can be chemically modified. Among the various surface modifications, the grafting of lactic acid oligomers (OLAs) is of special interest. In this paper, the first all-atom molecular dynamics simulation of nanocomposites of PLA filled with CNCs with surface-grafted OLAs is presented. The influence of the degree of modification of the CNCs with OLA chains on the PLA structure near the CNC surface and on the grafted OLA, as well as on the thermal and mechanical properties of the nanocomposites is studied. It is demonstrated that a 50% modification of CNCs with OLA chains leads to PLA expulsion from the CNC surface.

Summary: Self‐consistent field (SCF) theory is developed for a polymer brush immersed into a multi‐component solvent. Thermodynamics of the plane inhomogeneous brush is mainly determined by thermodynamics of the basic system, i.e., a homogeneous solution of a polymer dissolved in a multi‐component solvent that is in partial (or membrane) equilibrium with a bulk. Binary solvent with partially miscible components is in the focus of this investigation. The peculiarities of the brush are studied on the basis of the phase diagrams constructed for the basic system. Non‐trivial effects are demonstrated: microphase segregation of the brush and collapse of the brush under its filling with a good solvent in a pre‐binodal region of the bulk mixed solvent. Mathematical apparatus is developed and allows obtaining phase diagrams, density profiles, and other characteristics of the system under consideration.

The collapse of hydrophobic polyelectrolyte stars in aqueous solutions is studied using the Scheutjens−Fleer self-consistent field (SF-SCF) approach. The hydrophobic property of the segments tends to compact the stars, whereas the presence of charges has the opposite effect. As a result, star conformations can be switched from an extended, strongly hydrated, and swollen state to a collapsed state via semicollapsed, quasi-micellar state using control parameters such as the solvent quality, specified by the Flory−Huggins parameter, the pH value or the ionic strength. More specifically, there exists a range of parameters wherein the stars have an inhomogeneous radial structure with a collapsed region, referred to as the core, and a swollen region forming the corona. In such microphase segregated state the fraction of arms of the star that form the core, or alternatively escape into the swollen corona, can be controlled. The SF-SCF analysis is complemented with analytical models to rationalize the complex phase behavior.