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The dynamic characteristics of polymer chains grafted on to a flat inert surface and forming a monolayer are reviewed. For the chain in the monolayer the dependence of the times of large-scale movements in the direction perpendicular to the plane of grafting on the MM has the form τ ∼ N 3 , persisting with change in the grafting density and the quality of the solvent. The relations obtained are compared with the results of modelling monolayers by Brownian dynamics. The anomalous relaxation times of the chain in the monolayer are linked with the critical slowing close to the point of the coil-elongated chain phase transition. The equilibrium and dynamic behaviour of short impurity chains inserted into the monodisperse monolayer is examined.

A system of polymer chains grafted onto an inert planar surface to form a monolayer has been studied. It has been shown by evaluating the forces acting on each monomeric unit that the magnitude of the elongating force increases linearly with the distance of the unit from the surface. An analogy has been found between the behaviour of chains in the monolayer and chains subject to a longitudinal hydrodynamic field at a critical value of gradient; the latter lies in the middle of the phase transition coil-extended chain. The polymeric monolayer is a system stable inside the phase transition region. Reasons are pointed out that show the fallacy of the blob concept which considers the monolayer to be a weakly fluctiating system.

The separating power of gel permeation chromatography for polymers and globular proteins has been analysed theoretically. A relationship has been established between the optimum size of the separated polymer and/or protein and the pore size. All packings with unimodal pore-size distribution separate macromolecules over the same interval equal to about 1.5 in log M. The separating power for proteins is about 1.5 to 1.8 times lower than for flexible-chain polymers and the working range in log M is correspondingly wider.

A theory describing the structure of a monolayer of macromolecules densely grafted to a flat inert surface has been constructed. The theory is compared with the results of numerical calculations by the self-consistent filed method. The dependences of the mean height of the monolayer, the density profile, the chain distribution by height and the detaching force on the degree of polymerization and the density of the grafted chains have been obtained. The structural features of densely grafted chains and their difference from chains streched beyond the ends are discussed.

The Monte Carlo method has been used to examine the equilibrium characteristics of flexible chain concentrations in model lattices. Considered were the specific volume of the chain units and the reactions of random ones coming close together. The concentration effects have been considered by dividing all of the space into cubes of edges l = 5−21 long in which the periodic limiting conditions permit the formation of n chains composed of N = 16−121 units each. The studied concentration range was c = nN / l 3 , which varied from zero to c ≅0·7. The existence of forces of repulsion between chain units (a good solvent has been found to give rise to a mean square radius of inertia and number of intermolecular contacts in each of the chains which approached those for a separate chain in a θ solvent as the concentration increased). The same effect also applies to forces of attraction between chain units. In the concentration range c ⩾ c k , in which the intramolecular chain characteristics almost cease to change, there is overlapping of macromolecular coils when c k ∼[ ν ] θ −1 , in which [ ν ] θ −intrinsic viscosity of the dilute θ solution. For the inter-chain unit energy of reaction at the θ point there is no concentration dependence of the geometrical and thermodynamic characteristics of separate macromolecules.

The mean thickness and its fluctuation have been calculated by means of the self-consistent field lattice model for monolayers formed by flexible polymer chains grafted onto a planar insert surface at different graft densities σ−1. At σ⪆4 the mean layer height z obeys the relationship z≌0·52 Nσ−0·38 where N is the number of repeat units in the chain), in close agreement with the result of the scaling theory. Deviations from this formula appear in densely grafted systems, i.e., when the distance between the neighbouring chains drops below the length covered by two or three monomer units. Tke fluctuations in monolayer height are described by (z2-z2)12≌0·18 Nσ−0·325 a nd substantially exceed the fluctuations in size of an isolated macromolecule.

The diffusion of chains in slit shaped pores at different adsorption energies, is discussed on the basis of a lattice model without volume effects. Movement of the chain was produced by separate jumps of local kinetic units consisting of two monomer units, forming “corners” or Λ-units in the cubic lattice. The probability of detachment of units from the surface of the pores is assumed to be exponentially dependent on the energy of adsorption. It is shown that the coefficient of diffusion (D) of a chain in a pore is inversely proportional to the degree of bonding of the chain to the surface of the pore and is weakly dependent on pore width. The ratio D/D0 (where D0 is the coefficient of free diffusion of the chain) is independent of the molecular weight of the chain, in agreement with experimental results on the diffusion of polystyrene in porous glasses.

Using the self-consistent field method the authors calculate the profiles of the density of the monolayers formed by flexible lattice chains grafted to a flat inert surface. The differences of the results from the concepts of the scaling theory are discussed in detail.

The behaviour of a flexible model chain lattice is examined within a limited volume, i.e. the gap between smooth parallel surfaces. The free energy and the conformational structure of the macromolecules was found to depend only slightly on the dimensions of the gap when the forces of cohesion of the polymer chain units were fairly large; the former practically coincide with the structure of the chains adsorbed on the flat surfaces. The dependences of various chain characteristics, such as the free energy, the probability of loop and bridge formation, the proportion of linked chains, of units within the loops and bridges, etc., on the width of the slot-like gap are being examined, as well as the energy of the reaction between the chain units and the surfaces. The correlations of the calculated values with the problems of flocculation and stabilization of colloids is evaluated. Also under examination is the nature of the change from a free space to a gap macromolecules by means of a first order phase transition when the critical energy of the reaction between the polymer and the gap surfaces is reached. The liberated heat of transition is in a direct relation to the molecular weight of the polymer and diminishes as the dimensions of the gap increase. A distribution function has been formulated for the terminal chains in contact with the gap surfaces; it is of the bimodal type in the transition range.

The free energy F and the entropy S for flexible ( a 1 =0.75) and for stiffer ( a 2 =3.5) chains ( a being the persistent length) were calculated by the Monte Carlo method for a model of a non-self-intersecting chain on a simple cubic lattice. It was found that in flexible chains the free energy calculated per unit ceases to be a function of chain length in the case of a fixed intramolecular contact energy (− ϵ 0 ≅0.3) corresponding to the geometrical θ point. The free energy for a flexible chain unit is only slightly dependent on chain length and on solvent quality in the region of − ge ⪅0.1 ). There is a slight reduction in the entropy values for chains in “good” solvents, and the values are much lower in precipitants, particularly for rigid chains. On comparing the obtained dependences of F and S on ϵ with the analytical theory of Mazur it can be seen that intramolecular contacts in “good” solvents are realized via the formation of minimum sized loops, whereas interactions of remote units along the chain are of major importance in precipitants.

By simulation of polymer chains using a computer a study has been made of different characteristics of macromolecules adsorbed on a plane surface. As a model we took a self intersecting chain on a simple cubic lattice. The first unit of the chain is constrained to an adsorbing surface, and when any other chain units get onto the surface an energy gain ϵ results. The analysis covered flexible chains where there is equiprobability of trans - and gauche -isomers, and also stiffer chains with a preferred trans -configuration. The amounts of units adsorbed at the surface were calculated as well as the length of adsorbed and loop-like segments, the adsorbing layer thickness, the chain lengths and the areas covered on the surface by polymers with varying degrees of polymerization for different ϵ values. It is shown that in the region of polymer-surface energies below a critical level the number of polymer-surface contacts is small, irrespective of the length of the chain, whereas with energy values exceeding the critical level the number of contacts increases linearly with increasing numbers of chain units. In addition there is a redistribution of trans - and gauche -isomers in adsorbed and nonadsorbed parts of the macromolecules. Rigidization of the polymer chain increases the number of units in contact with the surface, and there is a sharpening of the transition from the nonadsorbed to the adsorbed state. The calculated adsorptive layer thicknesses characterized by the mean height of a chain end over the adsorbing surface are large in the pre-critical region, and depend on the molecular weight of the polymer chain, while in the post-critical region, on the other hand, the layer thickness is not a function of the chain length, and is small. It was found that the root mean square radius of inertia for an entire chain 〈 R 2 〉 is invariably proportional to MW, and varies relatively little with ϵ. At the same time the radius of inertia of the adsorbed part of a macromolecules is near zero in the region of low polymer-surface interaction energies, and approximates 〈 R 2 〉 in cases where the energies exceed a critical level.

It is shown that in certain “critical” conditions created in a chromatographic column the flexible polymer chains perform a phase transition of the first kind abruptly penetrating from the free volume of the mobile eluent into the narrow pores of the adsorbent. The experimental data on the chromatography of PS samples in a mixed eluent at different temperatures are reviewed showing that the width of the transition tends to zero as the MW of polystyrene increases. The legitimacy of using in chromatography the concepts “mobile and immobile phases” in terms of the theory of phase transitions is discussed.

Universal laws have been established for chromatography of polymers valid in presence of any adsorption interactions and for any ratios of the size of the macromolecules and the pore width of the adsorbent. Theory is compared with the experimental data on the chromatography of polystyrenes obtained with variation in the composition of the binary solvent and also with change in temperature allowing one to determine the mean thickness of the near-surface adsorption layers formed within the adsorbent pores.

Chromatographic separation of two-block copolymers according to composition has been treated theoretically. The copolymer was modelled by a Gaussian chain consisting of two blocks which differed in the energy of interaction with the surface of a slit-like pore. The partition coefficients have been derived in dependence on the energy of interaction between the polymer and the adsorbent and on pore width for copolymers of different length and composition. Critical conditions have been found for copolymers in narrow-pore sorbents and values of the partition coefficient have been derived.

A theory is constructed describing the equilibrium properties of Gaussian ring macromolecules of arbitrary length in pores of slit-like form. It is shown that in the GPC region the distribution coefficients Kd of the ring molecules somewhat exceed Kd of linear chains of the same molecular mass and the Benoit universal calibration is approximately fulfilled. In critical conditions corresponding to weak adsorption of the units for linear chains Kd = 1 and for ring molecules Kd ∼ 1 + √πRD and therefore “critical chromatography” can effectively separate long rings and linear chains. Scaling relations are obtained for Kd of Gaussian ring chains and chains with volumetric effects in narrow pores.

Theories have been formulated for the chromatographic separation by composition of larger block copolymers on porous adsorbents. The Gaussian chain consisting of two blocks reacting at differing energies with the pore surface of the adsorbent served as the polymer chain model. The adsorbent had slit-like pores with smooth and uniform walls. Functions have been obtained for the free energy of copolymer conformations in the pore as a function of the content of the “sticky” component ζ, for the energy of the reaction between the “sticky” and “non-sticking” blocks, and for the pore width. From some critical value ϵcr onwards the block copolymer (BCP) has been assumed to be adsorbed inside the pores, which facilitates its separation with respect to composition. The most effective separation of hetero-polymers with larger blocks will theoretically take place on adsorbents with narrow pores. In addition to gradient chromatography it is suggested that columns packed with a mixture of adsorbents possessing various pore sizes ought to be used. The selection of conditions critical for one of the components were found to make feasible the separation of two copolymers which is based on the length of the second block. The structure of the copolymers situated in the pores has been examined, and a detailed assessment has been made of the validity of this theory and of the possibility of separating copolymers according to the “architecture”.

The structure of macromolecules of a three block copolymer of the type ABA in selective solvents is discussed. Structural characteristics of copolymers with the Gaussian approximation and for flexible lattice chains have been calculated by computer modelling. It is shown that symmetrical three block copolymers have a dumb-bell structure which is retained over a wide range of selective solvents, from good solvents for the different blocks up to conditions corresponding to non-solvents. An increase in the molecular mass of the polymer chain, the ratio between the lengths of the middle and end blocks being constant, thus stabilizes the dumb-bell structure. It is shown that, although the overall dimensions of the chain are considerably decreased on going from good solvents for the end blocks to θ conditions (or a non-solvent), the dimensions of the middle block change only slightly and the links located in the end blocks touch only to a small extent. The intermolecular structures formed in solutions of two and three block copolymers are discussed.

A non-crossing chain model in a simple cubic lattice has been used to study the dynamics of an isolated macromolecule near an adsorbing flat surface by the Monte Carlo method. The rotation-isomeric movements of the macromolecule are shown as jumps of the randomly selected groups consisting of two and three chain units. The chain reaction with the surface is given as energy ϵ liberated when the chain unit comes in contact with the surface. The calculations have been made for − ϵ = 0·3–0·8 and polymerization degrees of N = 16 and 32. A study has been made of the time distribution of the chain contacting the surface and a theory introduced in which the macromolecule is adsorbed in two stages. The chain unit density has been examined at the moment of chain datachment from the surface.

Results of “machine experiments” with model lattice chains in slitted pores were compared with those of chromatographic experiments of the adsorption of PS by large pore silica gel. It was found possible to use the Gaussian chain in a slitted pore for the qualitative description of relations of polymer adsorption by porous adsorbents. The agreement between real and model chains suggests that phase transition of the first type predicted theoretically during the adsorption of macromolecules by porous adsorbents does, in fact, take place. The critical energy corresponding to the transition point is independent of the molecular weight of the polymer chain and the dimensions of adsorbent pores. With this energy of interaction the mechanism of chromatographic separation varies from the molecule sieve to the adsorption type. It is proposed to use the linear relation between the chromotographically measured variation of free energy of the chain −†F (or the logarithm of the distribution coefficient Kd) and the MD2 ratio or the D2ratio (M, being the molecular weight and the mean square radius of inertia of the macromolecular chain; D, average pore size of the adsorbent) for calibration in chromatographic analysis of polymers.

A method is proposed for evaluating the MD not requiring preliminary calibration against standards and based exclusively on the use of parameters of the recorded chromatogram. For this the authors employ the theoretical dependence relating the slope of the calibration curve to the distribution coefficient. The influence of adsorption effects on the widening of the chromatograms is considered. A new way of evaluating the instrumental widening is proposed using the form of the chromatograms close to critical conditions.

A cubic lattice model of a chain has been used to examine the effect of chain rigidity on its adsorption. The polymer-sorbent reaction has been taken into account by ascribing to it the energy −ϵ for each chain unit which attaches itself to the flat sorption surface. Energies below some critical value −ϵ ⪕ −ϵe have been found to cause the thermodynamic characteristics to coincide with those of a chain coiled in space. No consideration has been given to bulk reactions between chain units. The number of contacts between chain units and the sorption surface was found to be independent of chain length in this range. Where the reactions with the sorbent are strong however, i.e. −ϵ > −ϵc, the chain will attach itself to the4 surface with straight parts and the number of contacts will be equivalent to the contour line of the chain (contour length). The polymer chain suffers a phase transition of second order when ϵ = ϵc, and this is characterized by fracture due to the second component of free energy. The ϵc dependence on thermodynamic rigidity and the shape of the phase diagram are evaluated. The qualitative progress of the adsorption isotherm is examined at various points of the phase diagram.

A method which uses exclusively the chromatogram of the investigated sample is proposed for the determination of polymer polydispersity by gel permeation chromatography without resort to calibration by standards. A universal dependence between the reciprocal slope of the calibration curve and the distribution coefficient, which lies behind the proposed method, was tested experimentally. Determination of polydispersity without calibration is documented on the example of dextrans.

Two methods for the accurate theoretical description of adsorption of a flexible Gaussian macromolecule on a plane are discussed, i.e. the method of recurrent equations for lattice models and the method involving the use of a diffusional equation with boundary conditions of the third kind for the continuum model. A unique correspondence between the parameters indicating adsorption interaction is established, i.e. the correlational length of adsorption for the continuum model and the energy of adsorption of a unit for the lattice model. This correspondence applies at any chain length. Because of this correspondence both adsorption models give identical results.

The Monte Carlo method has been used to calculate equilibrium characteristics of model flexible copolymer chains differing as to the combination of blocks, but having identical compositions and contour lengths. The number of units was in all 64, and the number of microblocks varied from 2 to 64. Energies of homo- and hetero-contacts between pairs of attracted units varied within wide limits. Given equality of the homo- and hetero-contact energies the chain was a homopolymer containing “tagged” sections of varying length, which made it possible to determine the hierarchy of interactions in the polymer coils, namely, the extent to which the characteristics of a particular chain section are influenced by other sections positioned at various distances away from the former section along the chain. Local densities of units have been calculated, i.e. the number of intrachain contacts between units of a particular sort and between units belonging to different components. The structure of multiblock copolymers in selective solvents has been analyzed, and the conclusion formed that the copolymers must contain a number of quasi-globular chain sections (blocks) alternating with uncoiled blocks. Conditions under which globularized blocks merge into a single tangled clot-like formation are examined.

The separation of linear macromolecules with respect to functionality on porous adsorbents has been discussed theoretically, taking into account the adsorption both of functionally active end groups and also of the remaining links of the polymeric chain. The dependence of the retention volume of bi-, mono- and non-functional chains on their molecular weight, the adsorption energy of the functional groups and the adsorbent's pore width has been calculated for various interaction energies between the adsorbent and central non-functional links. Chromatograms, calculated for mixtures of bi-, mono- and non-functional model chains, highly disperse with respect to molecular weight, have been presented. It is shown that separation of oligomers with respect to functionality, without their preliminary fractionation with respect to molecular links (under critical conditions). The dependence of the effectiveness of the separation on the different parameters of the system is shown. The special features of the chromatographic separation of polymers under critical conditions are discussed.

An accurate theoretical analysis has been developed for regular block-copolymer (BCP) chains of various compositions on the boundary between the liquid and solid phases. The phase diagrams have been plotted, the thermodynamics and structural characteristics established for the adsorbed macromolecules. The adsorption of the long BCP molecules takes place by a second order phase change. The profile of the change will be the same as for the homopolymer when the energy of the actively sorbed component changes. A numerical increase of the actively sorbed chain units will make the adsorption start easier and enhance the bonding in the macromolecule. In the reverse case, when the energy of attraction is fixed and the energy changes of the component not active in the sorption, the curves for the transition will be diffuse. Where there is a large difference between the sorption capacities of the components at the boundary between the phases the polymer molecule will form a sequence of adsorbed parts and loops of a length depending on the “primary structure” of the chain. Such a regular structure will resist any external condition changes within a wide range.

The positron annihilation method has been used to evaluate free volume changes in films prepared from polyamic acid by thermal imidization. The method proved to be fruitful as a means of determination of the size of micropores, and for evaluating fluctuation free volume in the polymers. The positron annihilation method is also suitable for use in studies of the mechanism of formation of polyimides at the supermolecular level.

The Monte Carlo method and a computer were used to simulate the dynamic behaviour of an individual macromolecule in a dilute solution with a good solvent and without hydrodynamic interaction. The rotary-isomer motion of a macromolecular model on a cubic lattice was presented by the transition of groups of two or three units, selected at random. Calculations were carried out using degrees of polymerization N = 16, 32 and 64. It was shown that for a chain model with two types of mobile unit, in contrast with the chain with one type of mobile unit, correlation times of large scale fluctuations increase with an increase of the degree of polymerization N and N2 and are close to correlation times for a freely linked chain. Studies were made of correlation times of characteristics of individual units.

An equilibrium theory of the chromatography of flexible Gaussian chain macromolecules is constructed for different energies of adsorbent-linkage interaction and for arbitrary ratios of the chain dimensions and arbitrary widths of the slot-like pores. Ring chain distribution factors, a density profile for the units inside the pores, and the proportion of units on the walls of the porous adsorbent are obtained. The ring chain distribution factors under various conditions are discussed as a function of molecular weight.

Adsorption was examined on a charged plane of isolated chains with non-alternating dipole moments. It was shown that the adsorption of these macromolecules takes place intermittently, by first order phase transition. A phase diagram was obtained of the system for the cases, when the chain may be adsorbed by various ends and when it is crosslinked to the adsobent by a particular end. Accurate formulae were derived for the free energy, the proportion of adsorbed units and the perpendicular constituent of the dipole moment for infinitely long chains, according to the energy of adsorption and charge values on the adsorbent. The behaviour of polymers of finite length on charged sorbents is discussed.

Simple analytical expressions for the distribution coefficient of mono- and bifunctional macromolecules, adsorbed by their terminal groups on the walls of slit-like pores, have been obtained. The equilibrium behaviour of non-lattice functional chains was found to be described by the same rules as for flexible molecules. The influence of the adsorption of the middle units on separation according to functionality in critical conditions was examined by solving the diffusional equation, with reflecting boundary conditions.

The proposed theory describes the equilibrium properties of flexible Gaussian chains in slot-like pores for any ratio of chain dimensions R, slot with D and arbitrary energies of adsorption of units on pore walls. It is shown that there are five characteristic modes of behaviour covering the entire range of the R and D values and the adsorption energies. For each mode of behaviour analytical expressions were derived for the free energy of a chain, the density profile for units inside a pore and the fraction of units located on pore walls.

The diffusional flow of macromolecules through porous membranes containing pores of different size, has been calculated on the basis of a gaussian chain model. It was found that to obtain maximal flow a certain critical condition is necessary, namely maintenance of the small polymer-sorbent force of attraction that corresponds to the beginning of adsorption. Possible mechanisms of diffusional motion of macromolecules in pores and their relationship to the “reptation” mechanism of motion of chains through entanglements simulating a gel network, are discussed.

A method is proposed for calculating thermodynamic characteristics of flexible lattice model chains of finite length in slit pores with arbitrary energy of interaction between chain units and the pore surface. Molecular weight dependences were calculated for the combined state of chains with pore surface θN and the free conformation energy of chains in pores FN. It was confirmed that the critical energy which separates molecular-sieve and adsorption ranges in chromatography of polymers is independent of chain length (number of N units) and pore width D. It was found that θN and FN/N reach limiting asymptotic values in the adsorption region, independent of pore width and are only determined by the energy of adsorption, while in the exclusion region, 1when adsorption effects are suppressed, only depend on the ratio of chain dimensions and pore width. For short chains (or wide pores) FN ∼ (R2)12/D, while for long molecules, FN ∼ R2/D2 (R2 is the rms radius of inertia of macromolecules). Transition from one dependence to the other takes place when (R)212D≅0·11. Experimental results were analysed by chromatography of dextran on porous glass and these results confirmed theoretical predictions.

The paper describes the experimental checking of a novel method of chromatographic determination of the polydispersity of polymers under GPC conditions. With this new method no prior calibration against standards is required. The method is based solely on use of the chromatogram of the sample under study, and the polydispersity of new synthesized polymers may be determined in this way. To check the vilidity of the method, polystyrene standards were blended beforehand in certain fixed proportions, after which their chromatograms were obtained. The check tests showed that very satisfactory determination of the polydispersity of polymers is possible using the new method.

A computer has been used to model the behaviour of macromolecules of differing rigidities. A chain not intersecting itself has been used as the model on a cubic lattice. The solvent quality has been accounted for by incorporating forces of attraction (or repulsion) between each pair of chain units coming close together. Calculations have been made for chains with a rotation-isomeric mechanism of flexibility and with a mechanism described by persistent flexibility. Rigidization of the chain, regardless of the mechanism of flexing, reduced the energy of attraction (increased the temperature) corresponding to the θ point.

The adhesion of polymers to smooth surfaces is discussed from the point of view of adsorption of isolated, Gaussian chains, i.e. in a single-molecule approximation. External mechanical action is regarded as that of a constant potential field, exerting a stretching action on the macromolecule, either at its ends or at the ends and at loops simultaneously. It is shown that a polymer chain, stretched at its ends, retains its structure under small loads, and looses adhesive contact with the surface in a jerky manner by a transition of the first order, when the external force exceeds a certain critical level. It is suggested that intermittent change in chain structure in the surface layer can occur if the adhesive contains widely spaced crosslinkages, joining macromolecules in contact with the surface of the substrate to chains within the bulk of the adhesive. On the other hand stresses on all chain segments not in contact with the substrate (ends and loops), cause continuous rearrangement of the conformation of the polymeric component of the adhesive as the mechanical stress is increased.

The authors look at the theory of the chromatographic behaviour of short chains modelled by one, two and three freely articulated rigid portions (“rods”). The distribution coefficients have been obtained as a function of the length of the rigid portion, the energy of the polymer-adsorbent interaction, pore width and the thickness of the adsorption layer. In absence of adsorption on the walls of the pores the distribution coefficient of the oligomers is determined by the ratio of the mean spen of the molecule to the pore width. In the field of adsorption chromatography the dependence of the retained volume on M of the oligomers is non-monotonic. The degree of coherence of the oligomer with the pore surface essentially depends on the contour length, the number of fractures and the energy of interaction. Expressions are obtained for the distribution coefficients of the oligomers with terminal functional groups.

Chromatography under conditions critical for one type of units in a copolymer is discUSAsed. Provided the critical conditions apply to segments containing free ends, such as the outer blocks in a three-block copolymer or the side chains grafted onto a polymer backbone, these segments can be considered as chromatographically “invisible”, and chromatography under such critical conditions results in separation which proceeds exclUSAively according to the size of the “visible” component. In copolymers of a general structure the component to which the critical conditions apply becomes “invisible” only when chromatographed on a narrow-pore sorbent where the pore diameter is smaller than the block size.

Scaling concepts are used to obtain the distribution coefficients of linear and cyclic macromolecules in narrow pores in the GPC region. The distribution coefficients of self-non-intersecting linear chains and macrocycles in conditions of “critical” chromatography are discussed.

The behaviour in solution of a block copolymer molecule containing two blocks of the same length was simulated. A study was made of the effect of hetero-interactions on the dimensions of the entire chain and its separate blocks and on the average number of homo- and hetero-contacts. It was shown that when polymer components are incompatible the blocks are segregated as is the case with homopolymer chain segments in a good solvent. In the region where hetero-contacts are favourable from an energy point of view the blocks are displaced, accompanied by a sudden decrease in the dimensions of the entire chain and a slight reduction of individual block dimensions. The behaviour of a block copolymer molecule on changing temperature was analysed and it was shown that a sudden change may take place in the dimensions of the entire chain. Results were compared with experimental information concerning the temperature dependence of the intrinsic viscosity of block copolymers.

To check on the scaling theory the authors have modelled adsorption on the plane of a flexible macromolecule from different solvents. They calculate the characteristics of model lattice non-selfintersecting macromolecules partially solvated and present in a θ-solvent and determine their critical adsorption energies −ec. For chains in a θ-solvent the magnitude obtained −ec ⋍ 0·2 almost coincides with the critical energy of the Gaussian chain. For non-selfintersecting and “solvated” chains the critical energy is identical and equal to −ec ⋍ 0·3. The various relations of the scaling theory are used to determine the critical index ϕ. For non-selfintersecting and solvated molecules ϕ = 0·6 ± 0·03; for a θ-solvent ϕ = 0·5 ± 0·03. It is shown that the scaling concepts as a whole are confirmed by computer calculations although this requires knowledge of the critical energy −ec obtained in an independent manner.

The correlations between intramolecular movements (IMM) and average local chain unit densities are examined in a solution of macromolecules. The local density, in contrast with the average, was found to be almost independent of chain length in good solvents; it depended only on the thermodynamic rigidity of the chain and the radius of the individual, selected averaging region. There is a strong dependence of average and local densities of chain unit in poor solvents (precipitants) on the degree of polymerization. The IMM periods τ associated with small scale chain unit movements in the chain are assumed to be controlled by local changes and not by the average chain unit density. The experimental τ functions of solvent quality are evaluated with respect to polarized luminescence and dielectric relaxation of the polymers. Assessments of local chain unit density have been obtained for poly-p-chlorostyrene in various solvents from the dielectric relaxation periods as a function of concentration.

A theory is constructed for the chromatographic separation of flexible chain linear and ring macromolecules. Chromatograms are presented calculated for polydisperse ring macromolecules and for a mixture of them with similar linear chains for different energies of adsorption of the units on the pore walls. Analytical expressions have been obtained for the distribution coefficients of the linear and ring molecules and for the effectiveness of their separation in different chromatographic regimes. For the best separation of polydisperse macromolecules by their topology it is necessary to create conditions of weak adsorption intermediate between the regimes of GPC and “critical” chromatography.

The dynamic behaviour of a separate macromolecule has been modelled as a non-intersecting chain in a simple cubic lattice and simulated on a computer. The rotation-isomeric movements have been created by jumps of 2 and 3 chain units. The solvent quality has been varied by changing the intramolecular contact energy e. The calculations were carried out for e =0 (good solvent), − e =0·3 (θ-solvent) and −e-values of 0·5 and 0·8 (precipitant). The correlation times of the large-scale vibrations have been found to depend but slightly on the solvent quality and the mechanisms of these processes and of intramolecular reactions are the same as those for a Gaussian subchain model. The small-scale vibrations in the chain strongly depend on solvent quality due to the decisive effect of the local chain density on the correlation times. The dynamic characteristics of the chain have been calculated and experimentally measured by the polarizing luminescence and dielectrical relaxation methods.

A study was made of the formation of charge particles and free radicals in a number of polymers during photoradiation as a function of the intensity and integral dose of ionizing radiation, light intensity and frequency. A relation was established between the intensity of recombination luminescence and the dose of ionizing radiation and the formation of intermediate particles taking part in free radical formation during photoradiation. A correlation was derived between the frequency dependence of the photoradiation effect and optical absorption spectra of polymers subjected to γ-radiation at 77°K. It was shown that the formation of free radicals, in addition to those formed during radiolysis, by the action of photo-radiation is due to the use of the light energy absorbed by free radicals and stable products of the radiolysis of the polymer. The recombination mechanism of free radical formation and vibratory activation in charge recombination and deactivation of electron activated states of molecules was described.

A study has been made of the adsorption at a plane surface of isolated flexible lattice chains having a real volume. Solvent quality is allowed for by presetting a particular energy of interaction between units that have come near together. The number of chain units p bound by an adsorbent has been calculated, along with the adsorption constant K , in relation to molecular weigth, solvent quality and polymer-adsorbent interaction energy. The results are compared with similar experimental p vs. K relationships in the case of adsorption from a polymethylmethracrylate (PMMA) solution, with aerosil as the adsorbent. It is proposed that relations of p to solvent quality should be treated at a molecular level. The conformational transition of a macromolecule from the free state to the adsorbed state is discussed as a second degree phase transition, and the critical conditions for this transition are stated for the system PMMA-aerosil.