method for performing macrospace partitioning. [19][20][21][22] The polymers deposit to bridge a millimeter-scale gap between two substrates and a membrane grows downward from the air-liquid interface. During the drying of viscous solutions, the poly mer condenses and integrates itself at the air-liquid interface, oriented by capillary force. This induces suppression of water evaporation and meniscus splitting or macrospace partitioning in a limited space. Comparing with a single meniscus curve, the split multiple meniscus curves have an advantage for compatibility between evaporation and polymer deposition on larger area of air-liquid interface to form a dried polysaccharide membrane in vertical. [6,19] Rather than observing fingering patterns, as is typical, we successfully immobilized the fluid pattern to a solid pattern and obtained multiple membranes with highly oriented polysaccharide microfibers. In addition, by introducing a crosslinker into the membrane, uniaxially swellable hydrogels were formed, which is expected for anisotropic DDSs. [21] We have used several kinds of liquid crystalline (LC) polysaccharides with molecular weights of >10 6 g mol −1 , such as sacran and xanthan gum. [23] Using these polymers, we have clarified the effects of main factors such as initial polymer concentration, temperature, and the dimensions of the cell where the viscous liquids are filled.In this study, the meniscus splitting was simply regulated by the rate of water evaporation from an LC polysaccharide solution. In principle, the evaporation rate is controlled not by the temperature but by the relative humidity around the air-liquid interface. The depth of the air-LC interface in a container having a 1 mm gap should strongly affect the local humidity at a constant temperature. Using this relationship, the evaporation rate can be controlled without the temperature affecting the polymeric behavior in the liquid. To clarify the necessary conditions for meniscus splitting and bridging the millimeterscale gap, the polymer adsorption on the substrates was studied as well. Focusing on the orientation of the adsorbed polymer, the ordered deposition process is discussed.A viscous solution of xanthan gum was poured into a topside-open cell (X-width, Y-thickness, Z-depth) = (20, 1, 50 mm) at ≈25 °C. The 1 wt% aqueous solution has an extremely high viscosity of ≈0.3 Pa s at 25 °C and ≈0.7 Pa s at 60 °C. [22] The sample was placed under atmospheric pressure in an oven with an air circulator and the relative humidity was constant at Evaporative self-assembly of polymeric colloids is among the most attractive strategies for the preparation of soft materials with submicrometer-scale ordered structures. In this study, meniscus splitting from an aqueous solution of liquid crystalline (LC) polysaccharide xanthan gum is verified under conditions of controlled evaporative rate in a limited space. Under fast evaporation rate with a steep gradient of humidity above the air-LC interface, the meniscus splitting is induced to bridge the gap an...

On evaporative air‐water interface, polysaccharide microparticles of xanthan gum are capable of bridging millimeter scale gap between two substrates. The fast evaporation guides orderly polymer deposition and meniscus splitting to form a vertical membrane with uniaxial orientation. More details can be found in article number 1900855 by Kosuke Okeyoshi, Tatsuo Kaneko and co‐workers.