Drying dissipative structure of sodium salts of hyaluronic acid

Macroscopic and microscopic patterns during the course of dryness of aqueous solution in sodium salts of hyaluronic acid (NaHLA) were observed on a cover glass, a watch glass, and a Petri glass dish. Dendritic and rod-like microscopic patterns, which are similar to those of sodium salts of carboxymethyl cellulose, were observed for NaHLA especially on a cover glass and a watch glass. The microscopic patterns of NaHLA are supported to be originated from the hexose groups of polysaccharides, though the similar dendritic patterns are also observed for some of polynucleotides, sodium salts of deoxyribonucleic acid, and potassium salts of poly (riboadenylic acid), for example. Macroscopic broad ring size decreased substantially from the initial size of liquid and decreased slightly as polymer concentration decreased. These observations are consistent with existence of the rather strong interpolymer affinitive forces during the course of dryness. In the coexistence of sodium chloride, microscopic dendritic patterns grew large especially on a cover glass and a watch glass, which was so often observed for polysaccharides examined hitherto. Drying patterns are clarified to be formed by the successive and cooperative processes of evaporation, convection, sedimentation, and solidification.     

Drying dissipative structures of thermosensitive gel spheres of poly (N-isopropylacrylamide). Influence of gel size

Drying dissipative patterns of de-ionized suspensions (colloidal crystal-state at high concentrations) of the thermosensitive gels of poly (N-isopropylacrylamide) with various sizes (ca. 400–1,500?nm in diameter at 20?°C) were observed at 20 and 45?°C on a cover glass, a watch glass, and a Petri glass dish. The broad rings were observed and their size decreased as gel concentration decreased. Formation of the monodispersed agglomerated particles and their ordered arrays were observed irrespective of gel size. The macroscopic flickering spoke-like patterns were observed for the gel spheres from 70 to 600?nm in diameter at 20?°C, but almost disappeared for extremely large spheres, poly(N-isopropylacrylamide)(1500-5). This work clarified the formation of the drying microscopic structures of (a) ordered rings, (b) flickering ordered spoke lines, (c) net structure, and (d) lattice-like ordered structures of the agglomerated particles. The ordered rings became rather vague as gel size increased. The large net structures formed so often for large gels. Size effect on the lattice patterns was not recognized so clearly. The role of the electrical double layers around the agglomerated particles and the interaction of the particles with the substrate surfaces during dryness are important for the ordering. The microscopic drying patterns of gel spheres were quite different from those of linear type polymers and also from typical colloidal hard spheres, though the macroscopic patterns such as broad ring formation at the edges of the dried film were similar to each other.     

Drying dissipative structures of Chinese black ink on a cover glass and in a dish

Macroscopic and microscopic dissipative structural patterns are formed in the course of drying a suspension of Chinese black ink on a cover glass and in a dish. The time for the drying and the pattern area increased as the particle concentration increased. The broad ring patterns of the hills accumulated with the particles formed around the outside edges on a macroscopic scale. The height and the width of the broad ring increased as the particle concentration increased. The spokelike patterns of the rims accumulated with particles were also formed on a macroscopic scale. Microscopic patterns of colloidal accumulation were observed over the whole region of the pattern area. Various types of convection cells were observed on a cover glass and in a dish at 25–80 °C. A time-resolved observation of the drying process was also made. The convections of water and the colloidal particles at different rates under gravity and the translational and rotational Brownian movement of the particles were important for the macroscopic pattern formation. Microscopic patterns were determined by the translational Brownian diffusion of the particles and the electrostatic and the hydrophobic interactions between the particles and/or between the particles and the cell wall in the course of the solidification of the particles.     

Dissipative crystallization of aqueous solutions of hydroxypropyl cellulose

Drying dissipative structures of aqueous solutions of hydroxypropyl cellulose, their viscosities of 2 wt.% solutions ranging from 2 to 2,000 mPa.s were studied on a cover glass, a watch glass, and a Petri glass dish. The thickness profile of the dried film shows the coexistence of a low round hill and a high broad ring on a cover glass. The broad ring size increased as molecular weight and/or concentration of the polymers increased on a cover glass and a watch glass. Microscopic drying crystal patterns of HPC changed as a function of the distance from the film center, which is one of the typical results of the dissipative crystallization. Rod-like microscopic drying patterns originated in the cholesteric liquid crystalline structures were observed. The rods oriented mainly parallel and in some case perpendicularly to the radial direction of the dried film except the central area, where the rods distributed at random. These orientation effects were significant for low molecular weight samples and in a watch glass.     

Drying dissipative structure of sodium dextran sulfate in aqueous solution

Drying dissipative patterns were observed at room temperature on a cover glass, a watch glass, and a Petri glass dish during the course of dryness of aqueous solution of sodium salts of dextran sulfate (NaDSS) having molecular weights of 5000, 36,000 ~ 50,000 and 500,000. These biopolyelectrolytes are one of the typical polysaccharides. The influences of the hexose units upon the macroscopic and microscopic drying patterns are studied. Formation of some ordered structure is observed for NaDSS in high polymer concentrations especially on a cover glass. Broad ring size decreased as polymer concentration decreased and/or its molecular weight increased. Drying patterns are clarified to be formed by the successive and cooperative pattern formation of convection, sedimentation, and solidification.     

Dissipative crystallization of sodium salts of poly (d-glutamic acid), poly (l-glutamic acid), and their low molecular weight analogs

Drying dissipative patterns were observed at room temperature on a cover glass, a watch glass, and a Petri glass dish during the course of dryness of aqueous solution of sodium salts of poly (d-glutamic acid), poly (l-glutamic acid), and their low molecular weight analogs, monosodium d-glutamate, monosodium l-glutamate, and monosodium dl-glutamate. The low molecular weight analogs were hygroscopic and their drying patterns were observed in a dry box coexisted with the bags of desiccant. The broad rings, which are the typical macroscopic drying patterns, were observed for all the samples. Optical isomeric effects on the drying patterns were not recognized. Spherulite (or hedrite) and rod-like crystals from the assemblies of helical main chains of the polymers are formed mainly at the inner area from the broad ring (except central area) and the broad ring area, respectively. Coexistence of sodium chloride enhanced the crystal structures by the cooperative interactions between the polymers and the salts. The typical dissipative crystallization such as accumulation, segregation, and orientation effects of crystals were observed in the drying patterns.     

Inclusional association as studied by the drying dissipative structure. Part 2. Drying pattern of n-alkyltrimethylammonium bromide

Macro- and microscopic drying patterns were observed on a cover glass and a watch glass during the course of dryness of aqueous solutions of a series of n-alkyltrimethylammonium bromides (alkyl: n-decyl, n-dodecyl, n-tetradecyl, and n-hexadecyl). The broad rings formed at the outside edges of the macroscopic patterns. Size of the initial liquid on the substrates, d _i, that of the final broad ring, d _f, and the ratio, d _f/d _i, changed as the surfactant concentration changed, and there appeared a bending point in each curve, which was found to correspond to the critical micelle concentration (cmc) of the surfactant. The cmc values evaluated from the d _i, d _f, and d _f/d _i values agreed well with the reference values reported previously. Cooperative drying processes of the convection, sedimentation, and solidification were supported. Microscopic drying patterns such as rod-like, dendritic, and granule-like patterns were observed, and they changed as a function of the carbon number of the alkyl groups, surfactant concentration, and the distance from the center of the pattern.     

Dissipative crystallization of aqueous mixtures of potassium salts of poly(riboguanylic acid) and poly(ribocytidylic acid)

Drying patterns of aqueous solutions of potassium salts of poly(riboguanylic acid) (KPolyG), poly(ribocytidylic acid) (KPolyC), and their mixtures KPolyG + KPolyC were studied on a cover glass, a watch glass, and a glass dish at room temperature. Accumulation of the polymers forming the broad rings near the outside edge and also in the inner area of the dried film was observed. The fine multiple ring structures formed, which supports the fact that the affinity of the polymer with the substrate is strong. Typical microscopic drying patterns of KPolyG, KPolyC, and KPolyG + KPolyC were spherulites, dendritic long rods, and sword (harberd)-like rods, respectively. The patterns changed depending on the location in the dried film. The dendritic long rods and sword-like rods were assigned to the crystals of double-stranded and/or triple-stranded helices of the G:C and 2G:C complexes. Cross-like drying patterns that originated from the salt-polymer interaction are also observed. The relationship between the polymer complexation of KPolyG + KPolyC systems and the drying patterns is similar to that of KPolyA (potassium salt of poly(adenylic acid)) + KPolyU (potassium salt of poly(uridylic acid)).     

Convectional, sedimentation, and drying dissipative patterns of colloidal silica (183 nm in diameter) suspensions in a glass dish and a watch glass

Convectional, sedimentation, and drying dissipative structural patterns formed during the course of drying aqueous colloidal crystals of silica spheres (183 nm in diameter) have been studied in a glass dish and a watch glass. Spoke-like convectional patterns were observed in a watch glass. The broad ring sedimentation patterns formed especially in a glass dish within 30–40 min in suspension state by the convectional flow of water and colloidal spheres. The macroscopic broad ring drying patterns formed both in a glass dish and a watch glass. The ratio of the broad ring size in a glass dish against the initial size of suspension, i.e., inner diameter of the glass dish, d _f/d _i, in this work, were compared with previous work of other silica spheres having sizes of 305 and 560 nm and 1.2 μm in diameter. The d _f/d _i values in a glass dish increased as sphere concentration increased, but were rather insensitive to colloidal size. The d _f/d _i values on a watch glass also increased as sphere concentration increased, and further increased as sphere size decreased. Segregation effect by sphere size in a watch glass takes place by the balancing between the upward convectional flow of spheres in the lower layers of the liquid and the downward sedimentation of spheres. Colorful microscopic drying patterns formed both in a glass dish and a watch glass.     

Drying dissipative structures of lightly cross-linked poly(2-vinyl pyridine) cationic gel spheres stabilized with poly(ethylene glycol) in the deionized aqueous suspension

Drying dissipative patterns of deionized and colloidal crystal-state suspensions of the cationic gel spheres of lightly cross-linked poly(2-vinyl pyridine) stabilized with poly(ethylene glycol) were observed on a cover glass, a watch glass, and a Petri glass dish. Convectional patterns were recognized with the naked eyes. The broad rings were observed in the drying pattern and their size and width decreased as gel concentration decreased. Formation of the monodispersed agglomerated particles and their ordered arrays were observed. This work clarified the formation of the drying microscopic structures of (a) ordered rings, (b) flickering ordered spoke-lines, (c) net structure, and (d) lattice-like ordered structures of the agglomerated particles. The ordering of the agglomerated particles of the cationic gel spheres is similar to that of the anionic thermo-sensitive gel spheres of poly(N-isopropyl acrylamide). The role of the electrical double layers around the agglomerated particles and the interaction of the particles with the substrates during dryness are important for the ordering. The microscopic drying patterns of gel spheres were different from those of linear-type polymers and also from typical colloidal hard spheres, though the macroscopic patterns such as broad ring formation at the edges were similar to each other. The addition of sodium chloride shifted the microscopic patterns from lattice to net structures.     

Drying dissipative structures of aqueous solution of poly(ethylene glycol) on a cover glass, a watch glass, and a glass dish

Drying dissipative structures of aqueous solution of poly(ethylene glycol) (PEG) of molecular weights ranging from 200 to 3,500,000 were studied on a cover glass, a watch glass, and a glass dish on macroscopic and microscopic scales. Any convectional and sedimentation patterns did not appear during the course of drying the PEG solutions. Several important findings on the drying patterns are reported. Firstly, the crystalline structures of the dried film changed from hedrites to spherulites as the molecular weight and/or concentration of PEG increased. Secondly, lamellae were formed along the ring patterns especially at high concentrations and high molecular weights. The coupled crystalline patterns of the spherulites and the lamellae were observed in a watch glass along the ring structures, supporting the important role of the convection by the gravity during the course of dryness. The coupled patterns were difficult to be formed on a cover glass and a glass dish, except at the outside edge of the dried film. Thirdly, the size of the broad ring at the outside edge of the dried film especially on a cover glass and a watch glass increased sharply as the molecular weight increased and also as the polymer concentration increased. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Sedimentation and drying dissipative patterns of binary suspensions of colloidal silica spheres having different sizes

The sedimentation and drying dissipative structural patterns were formed during the course of drying binary mixtures among colloidal silica spheres of 183 nm, 305 nm, and 1.205 μm in diameter in aqueous suspension on a watch glass, a glass dish, and a cover glass, respectively. The broad ring-like sedimentation patterns were formed within several hours in suspension state for all the substrates used. Colorful macroscopic broad ring-like drying patterns were formed for the three substrates. In a watch glass, macroscopic drying patterns were composed of the outer and inner layers of small and large spheres, respectively. The two colored layers were ascribed to the Bragg diffractions of light by the dried colloidal crystals of the corresponding spheres. The width ratio of the layers changed in proportion to the mixing ratio of each spheres. In a glass dish, wave-like macroscopic drying patterns were observed in the intermediate areas between the outside edges of the broad ring and the inner wall of the cell. On a cover glass, the sphere mixing ratios were analyzed from the widths of the drying broad rings of the small spheres at the outside edge. High and distinct broad rings of small spheres and the low and vague broad one formed at the outer edges and in the inner area, respectively. Drying dissipative pattern was clarified to be one of the novel analysis techniques of colloidal size in binary colloidal mixtures.     

Drying dissipative patterns of aqueous solutions of poly (4-vinyl-N-alkyl-pyridinium halide)

Drying dissipative structural patterns of aqueous solutions of poly (4-vinyl-N-alkyl-pyridinium halide) were studied on a cover glass. The broad rings were observed at the outside edge of the dried film. The broad ring size (or the area of the dried film, S) increased as polymer concentration increased. The broad ring size decreased and then turned to increase when the hydrophobicity of the polymers increased. The drying time from the initial liquid (T) was insensitive to the polymer concentration. But, T was sensitive to the kind of polymers, i.e., hydrophobicity of polycations, and roughly in the opposite order to that of S. Spoke-like macroscopic patterns appeared clearly for poly (4-vinyl-N-n-butylpyridinium bromide) (C4PVP), but were not observed clearly for the other polymers. Cross-like microscopic patterns appeared from which the polymers with the extended conformation are deduced to be crystallized during the course of dryness. The cooperative crystallization took place between the polymer and the salt in the C4PVP + KCl mixtures. When two different polymers were mixed, segregation and then independent crystallization of each single component polymers were observed. The dissipative effect is important for determining of the polymer crystal structure during the course of crystallization.     

Sedimentation and drying dissipative patterns of ternary mixtures of colloidal silica spheres having different sizes

The sedimentation and drying dissipative structural patterns were formed during the course of drying ternary mixtures of colloidal silica spheres of 183 nm, 305 nm, and 1.205 μm in diameter in aqueous suspension on a watch glass, a glass dish, and a cover glass. The patterns were observed by closed-up pictures, metallurgical optical microscopy, 3D profile microscopy, reflection spectroscopy and AFM images. The concentrations of the three spheres ranged from 0.0023 to 0.0128 keeping the same concentrations for each spheres. Broad ring-like sedimentation patterns were formed within a short time in suspension state especially in a glass dish. In a watch glass, colorful three layered ring-like drying patterns were observed and composed of the outer, middle and inner layers of small, medium, and large spheres, respectively. The three colored segregated layers were formed by the balancing between the outward convectional flow and the inward sedimentation of spheres. In a glass dish, wave-like macroscopic drying patterns were observed in the intermediate areas between the outside edge of the broad ring at the central area and the inner wall of the cell especially at low sphere concentrations. The size of the broad ring at the central area increased as sphere concentration increased. On a cover glass, size segregation also took place, i.e., small, medium, and large spheres located at the outer, medium, and central areas, though these segregations were not so complete compared with those on a watch glass.     

Dissipative crystallization of poly-d-lysine hydrobromide, poly-l-lysine hydrobromide, and their low-molecular-weight analogs

Drying dissipative structures of aqueous solutions of poly-d-lysine hydrobromide, poly-l-lysine hydrobromide, and their low-molecular-weight analogs were studied on a cover glass, a watch glass, and a Petri glass dish. Size of the broad rings, one of the typical macroscopic patterns, decreased as the solute concentration decreased. Microscopic drying crystal patterns of polylysine hydrobromides and their low-molecular-weight analogs, i.e., d-, l-, and dl-lysine hydrochloride changed as a function of the distance from the film center, which is one of the typical features of dissipative crystallization. Macroscopic and microscopic drying patterns were quite similar to each other irrespective of their stereospecificity. The crystal patterns of the mixtures of poly-d-lysine hydrobromide and poly-l-lysine hydrobromide were also similar to those of the corresponding single-component polymers. The stereospecific effects were not observed in this work.     

Drying dissipative structures of thermo-sensitive gel spheres of poly(<Emphasis Type="Italic">N</Emphasis>-isopropylacrylamide) with low degree of cross-linking

Drying dissipative patterns of deionized suspensions (colloidal crystal state at high concentrations) of the thermo-sensitive gels of poly(N-isopropylacrylamide) with low degree of cross-linking of 0.5% (318 nm and 116 nm in the hydrodynamic diameter at 25 °C and 45 °C) were observed at 20 °C and 45 °C on a cover glass, a watch glass and a Petri glass dish. The broad rings were observed and their size decreased as micro-gel concentration decreased. Formation of the monodispersed agglomerated particles and their ordered arrays were observed. This work clarified the formation of the drying microscopic structures of (a) flickering ordered spoke-lines, (b) ordered rings, (c) net structure, and finally (d) lattice-like ordered structures of the agglomerated particles. The net and lattice structures formed more favorably at higher temperatures and/or higher degree of cross-linking of the gels. Importance of the convectional flow of the agglomerated particles during the drying processes is supported for the ordered array formation. The role of the electrical double layers around the agglomerated particles and the interaction of the particles with the substrate surfaces during dryness are also important for the ordering. The microscopic drying patterns of gel spheres were quite different from those of linear-type polymers and also from typical colloidal spheres, though the macroscopic patterns such as broad ring formation at the edges of the dried film were similar to each other.     

Dissipative structures formed in the course of drying an aqueous solution of poly(allylamine hydrochloride) on a cover glass

Macroscopic and microscopic dissipative structural patterns formed in the course of drying a deionized aqueous solution of cationic polyelectrolyte, poly(allylamine hydrochloride) on a cover glass have been observed. Drying times range from 40 min at 45 °C to 450 min at 5 °C, and are insensitive to the polymer concentration. Pattern area shrinks toward the center at the low polymer concentrations, and increases as the concentration increases. A macroscopic broad ring pattern, where the polymer accumulates densely, forms in many cases. Beautiful fractal patterns are observed at the microscopic scale. The fractal dimension increases from 1.2 to 1.6 as polymer concentration increases from 10^-6 monoM to 10^-2 monoM. The relative rates between the water flow at the drying front and the convection flow of water accompanying the movement of polymer are important for the macroscopic and microscopic pattern formation.     

Drying dissipative structures of cationic gel spheres of lightly cross-linked poly(2-vinyl pyridine) (170 ∼ 180 nm in diameter) in the deionized aqueous suspension

Drying dissipative patterns of cationic gel crystals of lightly cross-linked poly(2-vinyl pyridine) spheres (AIBA-P2VP, 170?～?180 nm in diameter) were observed on a cover glass, a watch glass, and a Petri glass dish. Convectional patterns were recognized with the naked eyes. Two kinds of the broad rings were observed at the outside edge and inner region in the macroscopic drying pattern, and their size at the inner regions first decreased and then turned to increase as gel concentration decreased. Formation of the similar-sized aggregates, i.e., hierarchical aggregation and their ordered arrays were observed. This work supported strongly the formation of the microscopic drying structures of (a) ordered rings, (b) flickering ordered spoke-lines, (c) net structure, and (d) lattice-like ordered structures of the aggregated particles. The ordering of the similar-sized aggregates of the cationic gel spheres (AIBA-P2VP) in this work is similar to that of the large cationic gel spheres of poly(2-vinyl pyridine) (385?～?400 nm in diameter) and further to that of the anionic thermosensitive gel spheres of poly(N-isopropyl acrylamide). Role of the electrical double layers around the aggregates and their interaction with the substrates during dryness are important for the ordering. The microscopic drying patterns of gel spheres were different from those of linear-type polymers and also from typical colloidal hard spheres, though the macroscopic patterns such as broad ring formation were similar to each other.     

Dissipative crystallization of aqueous solution of sodium polymethacrylate

Drying dissipative structures of aqueous solution of sodium polymethacrylate (NaPMA) were studied on a cover glass, a watch glass, and a glass dish. Any convectional and sedimentation patterns did not appear during the course of dryness. Several important findings on the drying patterns are reported. Firstly, spherulite and hedrite dissipative crystals were observed when the polymer solutions were dried. The crystalline structures changed from hedrites to spherulites as polymer concentration increased. Secondary, the coupled structures of the spherulites and the broad rings were observed for NaPMA at the outside edge of the broad ring. However, the coupled crystalline structures of the lamellaes from the broad ring and the spherulites, which were observed for poly(ethylene glycol) (Okubo et al. 2009), were not observed clearly for NaPMA system. Thirdly, size of the broad ring at the outside edge of the dried film increased sharply as polymer concentration increased.     

Dissipative crystallization of aqueous mixtures of potassium salts of poly(riboadenylic acid) and poly(ribouridylic acid)

Dissipative drying patterns of aqueous mixtures of potassium salts of poly(riboadenylic acid) (KPolyA) and poly(ribouridylic acid) (KPolyU) were studied on a cover glass, a watch glass and a glass dish at room temperature. Accumulation of the polymers forming the broad rings near the outside edge and the inner area of the dried film was observed. The fine multiple ring structures formed when the affinity of the polymer with the substrate is strong. Microscopic drying patterns changed drastically depending on the location in the dried film. Microscopic drying patterns were mainly dendritic long rods and sword (halberd)-like rods. They are assigned to the crystals of double-stranded and triple-stranded helices of the A:U and A:2U complexes, respectively. Cross-like drying patterns are also observed originated from the salt-polymer interaction.