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Introduction
Publications
Publications (158)
This 2-volume set includes extensive discussions of scattering techniques (light, neutron
and X-ray) and related fluctuation and grating techniques that are at the forefront of this
field. Most of the scattering techniques are Fourier space techniques. Recent advances
have seen the development of powerful direct imaging methods such as atomic force...
The synthesis, characterization, and some studies of the dynamics of a new rod/sphere composite liquid are discussed here. The composite liquid consists of silica spheres (39.4 and 60.4 nm radius) and poly(γ-benzyl-α,L-glutamate) rods (102 000 and 249 700 g/mol molecular weight) dispersed without aggregation in dimethylformamide (DMF) or a mixture...
Experimental data on the rotation and translation of rigid rod macromolecules in the semi‐dilute region are discussed in the terms of the Doi‐Edwards theory. Available data indicate that the rotational diffusion coefficients vary approximately as the inverse concentration squared and the inverse length to a power between 7 and 8. The absolute value...
Some applications of depolarized light-scattering spectroscopy to the study of rigid macromol- ecules in solution are described. The depolarized light-scattering method can be used to obtain ro- tational diffusion coefficients and static and dynamic correlation factors of rigid macromolecules. In molecules exhibiting some flexibility, intramolecula...
Biological polymers and structures, including proteins and DNAs, can be made in essentially monodisperse form. Proteins usually have well-defined shapes. Duplex oligonucleotides are rigid and rodlike, and longer DNAs are semiflexible coils. The DNAs also constitute a homologous series. The dynamics of both proteins and DNAs can be studied by readil...
We have reanalyzed our former static small-angle x-ray scattering and photon correlation spectroscopy results on dense solutions of charged spherical apoferritin proteins using theories recently developed for studies of colloids. The static structure factors S(q), and the small-wave-number collective diffusion coefficient D(c) determined from those...
The long-time self-diffusion coefficients of a 20 base pair duplex oligonucleotide are measured as functions of 20-mer and added NaCl salt concentrations. The self-diffusion coefficients decrease monotonically with increasing 20-mer concentrations for the high-added salt sample and display non-monotonically decreasing 20-mer concentration dependenc...
The dynamic properties of suspensions of rodlike cellulose microcrystallites (whiskers) are investigated using polarized and depolarized dynamic light scattering (DLS, DDLS) and transient electric birefringence (TEB). The whiskers were prepared by controlled sulfuric acid hydrolysis from cotton and tunicate cellulose fibers. Translational (D) and r...
We review experimental and theoretical work on model rod-sphere composite liquids, emphasizing the dynamics of the spheres and the rods. We first present a survey of experimental techniques that may be used to study composite liquids, and then a brief review of “depletion forces” in colloidal composites. We discuss translational motions of probe sp...
This volume is based on lectures given at the NATO-Advanced Study Institute on Structure and Dynamics of Polymer and Colloid Systems held in Les Houches, France from September 14-24, 1999. The meeting arose from a perceived need to bring together scientists studying the polymer and colloid fields. Although these fields are intertwined and share man...
Static and dynamic scattering properties of(a-b) diblock copolymer chains having different architectures are discussed in the framework of the random phase approximation (RPA)I The case of a symmetric diblock (50/50) in a solvent satisfying the zero average contrast condition,in the semidilute regime, is considered in detail. We, in particular, cal...
Dynamic light scattering (DLS) and small-angle neutron scattering (SANS) are used to characterize the structure and dynamics of ternary solutions consisting either of rods or "hairy rod" polymers and polystyrene (PS) coils in a solvent composed of chloroform saturated with (<0.5%) formamide (CF). The rods are poly( -benzyl-alpha -L-glutamate) (PBLG...
The dynamics of three monodisperse linear duplex DNA fragments—a 2311 base pair restriction fragment and 1500 and 1100 base pair polymerase chain reaction fragments—in dilute solution are studied as functions of added salt (NaCl) concentration by dynamic light scattering-photon correlation spectroscopy. Translational diffusion coefficients and intr...
Dynamic light scattering (DLS) techniques for studying sizes and shapes of nanoparticles in liquids are reviewed. In photon correlation spectroscopy (PCS), the time fluctuations in the intensity of light scattered by the particle dispersion are monitored. For dilute dispersions of spherical nanoparticles, the decay rate of the time autocorrelation...
Transient electric birefringence decay studies of the rotation of rodlike polymers in solutions with spherical particles have been performed as a function of the sphere volume fraction. The rodlike polymers are helical poly-γ-benzyl, α-L-glutamates of several lengths. The spheres are coated silica particles and the solvent is a mixture of dimethyl...
Dynamic light scattering (DLS) and transient electric birefringence decay measurements are performed on poly(γ-benzyl-α-l-glutamate) solutions over a wide concentration range. We interpret the primary dynamic decay rate always observed from dynamic light scattering experiments by extending the expression for the decay rate beyond the original limit...
The peak in the small angle x-ray scattering and the dynamic light-scattering slow mode for a 20 base-pair duplex oligonucleotide (``B-DNA'') are studied as functions of oligonucleotide and added-salt (NaCl) concentrations. Both the x-ray peak intensity and the relative intensity of the slow mode decrease as the added-salt concentration is increase...
The dynamics of a 20 base pair oligonucleotide is studied by dynamic light scattering-photon correlation spectroscopy and depolarized Fabry–Perot interferometry. The 20 base pair oligonucleotide is a well-defined, albeit short, rigid rod molecule that serves as a model for polyelectrolyte solution dynamics. The effects of added salt on the solution...
Dynamic light scattering of pure cholesteric and polymer-stabilized cholesteric liquid crystals shows two relaxation modes: twist and viscous-splay (umbrella). The twist mode is diffusive, whereas the frequency associated with the viscous-splay deformation goes to a constant at zero scattering angle. In the presence of polymer networks the frequenc...
The dynamic behavior of a nematic liquid crystal is investigated by photon correlation spectroscopy. Two relaxation modes, the so-called splay and twist, are identified for a specific experimental geometry involving the directions of the wave vector q, the polarizations of the incident and scattered beams, and the vector director of the nematic liq...
Static and dynamic properties of a DNA fragment of molecular weight 316 800 (contour length 1632 Angstrom) in semidilute solutions are studied by small-angle neutron scattering (SANS) and static (SLS) and dynamic light scattering(DLS). SANS experiments in a solution with DNA concentration C-p = 42 mg mL(-1) were performed as functions of added salt...
Depolarized dynamic light scattering (DDLS) experiments are performed on the glass forming materials ortho terphenyl (OTP), bis-methyl-methoxy-phenyl-cyclohexane (BMMPC), and bis-methyl-phenyl-cyclohexane (BMPC). Depolarized spectra are obtained for the bulk liquids and for solutions of varying concentration in CCl4 . Effective optical anisotropies...
The rate of translational diffusion of skeletal muscle myosin subfragment 1 (S1) was determined from polarized dynamic light scattering autocorrelation measurements. Diffusion rates were expressed in terms of the hydrodynamic radii Rh. At 20 degrees C, in low ionic strength pH 8 solutions, Rh increased from 4.3 nm to 5.7 nm as [S1] was increased fr...
The translational and rotational dynamics, including the translational−rotational coupling, of collagen in an aqueous 0.25 mg/mL solution of 0.1 N HCl were studied by polarized dynamic light scattering. An autocorrelator with variably spaced delayed times allowed computation of dynamic light-scattering intensity autocorrelation functions over a wid...
In this work we investigate the equilibrium structure and short-time dynamics of moderately concentrated suspensions of polydisperse charged silica particles immersed in a nearly optically matched solvent. We measure the static structure factor SM(q) and the first cumulant of the intensity autocorrelation function with static and dynamic light-scat...
Dynamic light scattering-photon correlation spectroscopy (PCS) has been used to study the dynamics of a 2311 base pair (bp) superhelical plasmid DNA in dilute and semidilute solutions. In dilute solution, translational and rotational/internal modes could be resolved. Assuming that the DNA is a rigid rod, the translational diffusion coefficient dete...
Light scattering has been used for about the past 25 years to determine such static properties of polymers in solution as molecular weights, solution virial coefficients, molecular shapes and characteristic dimensions, molecular optical anistropies and molecular weight and size distributions of polydisperse samples.1 In all of these cases the measu...
Dynamic light scattering (DLS) and static light scattering (SLS) were used to characterize the structure and dynamics of solutions of polystyrene of molecular weight 390 000 in 1,1,2,2-tetrachloroethane. Mutual diffusion coefficients were determined as functions of concentration and temperature. The diffusion virial coefficients were determined and...
The dynamics of macromolecules in ternary solutions consisting of a probe polymer, a matrix polymer, and a solvent were studied using dynamic light scattering (DLS) with refractive index matching and, as supporting techniques, static light scattering and viscometry. The probe was linear polystyrene of molecular weight 390,000, which was always pres...
The ionic strength dependences of the translational diffusion coefficient and the first internal mode relaxation time of monodisperse 2311 base pair relaxed circular DNA were studied by dynamic light scattering. Intensity autocorrelation functions were analyzed using the inverse Laplace transform method (CONTIN). Above the lowest scattering angle s...
Five composite liquid solutions (CL1-5) were prepared consisting of silica spheres and the rigid rod polymer poly((gamma) -benzyl-(alpha) ,L-glutamate) (PBLG) in the polar organic solvent dimethylformamide. The sizes of the macromolecular components in each solution were chosen such that the sphere radius/rod length ratio decreased from CL1 to CL5....
A brief summary of the basic principles of the dynamic light scattering-photon correlation spectroscopy technique is given. Experiments on DNA in both dilute and nondilute solutions are used to illustrate both the types of information that may be obtained from DLS-PCS as well as some of its limitations.
Five composite liquids consisting of the rigid rod polymer poly(gamma-benzyl alpha,L-glutamate) and narrowly dispersed, spherical silica particles were studied in the solvent dimethylformamide by dynamic (DLS) and total intensity (TILS) light scattering. The diffusion constant of the spheres was measured by DLS. The effects of sphere size, rod leng...
A new rod/sphere composite liquid was synthesized, characterized, and studied by dynamic light scattering (DLS). The liquid consists of coated silica spheres and poly(gamma-benzyl-alpha,L-glutamate) rods (PBLG) in dimethylformamide (DMF). Diffusion constants for spheres of radius 60.4 nm and PBLG rods of length 70 nm were measured by DLS in binary...
Dynamic light scattering has been used to study the dynamics of a 2311bp (base pair) circular DNA at two different ionic strengths. The measured intensity autocorrelation functions at different scattering vector lengths were analyzed by the inverse Laplace transform program, CONTIN, to separate translational and internal motions. The translational...
The molecular dynamic form factor for the Rouse-Zimm free-draining Gaussian ring is calculated in a form which facilitates comparison with experimental scattering data. The relative contributions of the pure translation mode and various internal modes are given. At zero time, the dynamic form factor reduces to the well-known Casassa result for the...
Composite liquids – liquids composed of polymers, particles, and small molecule solvents – constitute an important class of synthetic and naturally occurring materials. Examples include molecular composites, ceramic precursors, lubricants, adhesives, and the cytoplasm in biological cells. Due to the complexity of these liquids, experimental studies...
The scattered light intensity autocorrelation functions of dilute and semidilute solutions of sonicated calf thymus DNA fragments in the presence of 0.2 M NaCl were measured. In addition, the weight-average molecular weight and the second virial coefficient of this system were determined by low-angle laser light scattering (LALLS). The weight-avera...
Well-defined, monodisperse, homologous series of oligonucleotides and DNA restriction fragments may now be produced and used as models of rigid and semirigid rodlike molecules in solution. Information from optical experiments on these model systems aids in the formulation and testing of theories of macromolecular dynamics in both dilute and concent...
Rotational and translational diffusion coefficients in aqueous solution of a series of three B duplex oligonucleotides 8, 12, and 20 base pairs in length are measured by depolarized and polarized dynamic light scattering, respectively. Theoretical relations for the diffusion coefficients of short rods by Tirado and Garcia de la Torre are used in co...
The technique of Brownian dynamics simulation is used to study dynamic light scattering (DLS) from a linear 2311-bp fragment of DNA. A variety of different semistiff models are considered, and the simulation results are compared with actual experiments. The parameters of the model are chosen subject to the constraints that the overall translational...
Dynamic light scattering time correlation functions from dilute solutions of linear, monodisperse DNA restriction fragments, ranging in size from 367 to 2311 base pairs (molecular weight from 0.24 to 1.5 million), were measured at 20°C, in 100 mM NaCl, 10 mM Tris·HCl, and 1 mM EDTA (pH 8). The correlation functions were analyzed by using CONTIN, a...
The dynamics of three synthetic oligonucleotides d(CG)4, d(CG)6, and d(CGCGTTGTTCGCG) of different length and shape were studied in solution by depolarized dynamic light scattering (DDLS) and time-resolved nuclear Overhauser effect cross-relaxation measurements. For cylindrically symmetric molecules the DDLS spectrum is dominated by the rotation of...
Velocity cross-correlation coefficients (VCC's) may be used as measures of the coupling between the velocities of different molecules in binary liquid mixtures. The hydrodynamic expression for the VCC's proposed by Friedman and Mills is used to derived expressions for the VCC's in terms of molecular diameters and the Kirkwood-Buff parameters. The m...
The reorientation dynamics of a homologous series of n-alkyl p-chlorobenzoate solvent molecules mixed with poly(methyl methacrylate) were studied by depolarized Fabry-Perot interferometry. The n-alkyl groups varied from methyl to n-pentyl. The solvent concentrations ranged from 60 to 30 wt % and the temperatures from 20 to 80 degree C. The glass tr...
The depolarized light scattering reorientation times of a series of n-alkyl p-chlorobenzoates (PCAB's) (with n-alkyl varying from methyl to n-pentyl) have been measured in the neat liquids and in 16% (vol/vol) solutions in CCl//4 at various temperatures. Densities and viscosities of the neat liquids and viscosities of the 16% solutions were also me...
Dynamic light scattering time correlation functions from a solution of monodisperse, blunt-ended 2311 base pair DNA restriction fragment were measured at 20 degree C, in 100 mM NaCl, 10 mM Tris-HCl, and 1 mM EDTA (pH 8) at DNA concentrations ranging from 90 to 450 mu g/mL. The correlation functions were analyzed by using CONTIN, a constrained inver...
Brownian dynamics simulations of a three‐bead and a ten‐bead model of a flexible linear macromolecule in solution are performed. Dynamic forward depolarized light scattering autocorrelation functions are calculated from these dynamic simulations to a delay time of 30 μs and are analyzed by the program contin, yielding the simplest distribution of d...
Theories of caging of rigid rodlike molecules of length L and diameter d in semidilute solution are extended to higher concentrations. Packing considerations indicate that ordering in concentrated rigid rod systems must occur below CL2d = 2.26, where C is the number concentration of rods. In addition, the concentration at which the mean square defl...
The mutual diffusion coefficients of the water-rich region of the 2-butoxyethanol (BE)water system were measured by dynamic light scattering at 10, 25, and 40/sup 0/C. At mole fraction of BE greater than 0.02 (X/sub BE/ greater than or equal to 0.02), the results were in good agreement with the work of T. Kato. Below X/sub BE/ = 0.02 an anomalous d...
We examine the effects of the electric field strength and the orienting pulse duration on the measured decay of the transient electric birefringence of a blunt-ended DNA restriction fragment 1010 base pairs in length (molecular weight 670 000) in solution. Effects of pulse length on the distribution of decay times which were shown in an earlier wor...
The hypersonic speed of sound (C/sub h/) has been measured in the tert-butyl alcohol-water system (TBA/water) from 0.0 to 0.16 mole fraction of TBA at 10-45 /sup 0/C by Brillouin scattering. Considerable dispersion in the C/sub h/ as compared to that found in the zero frequency and ultrasonic range is observed. The isentropic compressibilities in t...
We report electric birefringence measurements on four blunt-ended DNAs 367, 762, 1010, and 2311 base pairs in length. The multiexponential zero-field birefringence decay was resolved into separate components by automatic computer programs that do not require any a priori knowledge of the number of decay processes existing in the data. The slowest o...
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A geometrical model of the "caging" of thin, rigid rods in semidilute solution is used to find the concentration and length dependences of both the maximum allowed rotation angle and the rotational diffusion coefficient of rods trapped in cages. This model may explain some of the discrepancies which have been found in the past between measurements...
Fabry-Perot interferometry is used to observe the depolarized dynamic light scattering (DDLS) spectra of p-chlorodiphenylmethane (CPM) and of poly(methyl methacrylate) mixtures with CPM. The DDLS spectra are recorded from -4 to +98°C with several experimental interferometer spacings, which allow detection of reorientational motion throughout the 20...
Scitation is the online home of leading journals and conference proceedings from AIP Publishing and AIP Member Societies
The dynamics of free-draining polymers in dilute solution are treated with the Kratky-Porod wormlike chain model. The model consists of differentiable space curves of constant length with bending elasticity. We show that eliminating the stretching elasticity gives an internally consistent model which satisfies the pure bending Langevin equation of...
We report dynamic light scattering and transient electric birefringence data on five monodisperse plasmid DNAs ranging in molecular weight from 1.5 × 106 to 8.4 × 106 daltons. The translational behavior closely follows the experimental sedimentation work of Hudson and Vinograd (Nature (London), 221, 332-7 (1969)) while the apparent rotational relax...
We have constructed three plasmids, pLH2311, pLH1010, and pLH762/367, that can be used to produce large amounts of monodisperse DNA fragments by cleavage with the readily available restriction enzymes Pvu II and Hae III. pLH2311 produces a single fragment 2311 base pairs (bp) in length (1.5 × 106 dalton molecular weight) when cut by Pvu II. pLH1010...
The general solution to the scattered electric field time autocorrelation function for a dilute system of cylindrically symmetric, optically anisotropic particles undergoing coupled translational-rotational diffusion is presented. The solution is exact within the Rayleigh–Gans–Debye approximation. The scattered time autocorrelation function is an i...
Most photon correlation experiments, as may be determined from a perusal of the articles in this book, measure time correlation functions of the polarized scattered light. The depolarized scattered light is, however, a rich source of dynamic and structural information which is often not readily obtainable by other techniques. The major reason for t...
In the twenty years since their inception, modern dynamic light-scattering techniques have become increasingly sophisticated, and their applications have grown exceedingly diverse. Applications of the techniques to problems in physics, chemistry, biology, medicine, and fluid mechanics have prolifer ated. It is probably no longer possible for one o...
The dynamic light scattering technique of photon correlation spectroscopy is used to detect translational, rotational, and internal motions of micelles in solution. The results obtained can best be explained by a micellar growth model. Micelles have polydisperse size distributions which lead to photon correlation spectra consisting of a sum of expo...
Dynamic light scattering (DLS) is a major method for studying the dynamics of rodlike particles in solution and suspension. The recent development by Provencher of a smoothed inverse Laplace transform technique for analyzing DLS time correlation functions allows an objective determination of the distribution of relaxation times in the system to be...
Resonance enhanced dynamic depolarized Rayleigh scattering is used to measure reorientation times of two nitrophenolate anions in millimolar aqueous and ethanolic solutions. Reorientation times of the corresponding neutral molecules in 0.01 to 0.1 M solutions are also reported. The reorientation time of 3,4-dinitrophenolate anion has a linear visco...
A general and transparent theory for the Rayleigh-Debye scattering from rigid spheres (solid, hollow, or infinitely thin shells) composed of anisotropic elements is presented and applied to the particular case of phospholipid vesicles. Equations are derived for the horizontal depolarization ratio pH = IHH/Ivv, which is predicted to be nonzero for s...
A theory for the dynamic light scattering intensity time correlation functions of dilute solutions of once-broken rods is developed. The rods are assumed to be small enough so that intramolecular interference can be neglected and the amount of bending at the joint is restricted to some maximum angle. Both polarized and depolarized correlation funct...
Depolarized light scattering and high-resolution 1H NMR measurements were made on solutions of light meromyosin (LMM) and myosin rod in 0.6 M KCl-0.010 M pyrophosphate, pH 9.5, at 20 degrees C. The light scattering data indicated LMM is a rigid molecule. Myosin rod is best described as a once-broken rod with domains that can freely diffuse in conic...
The depolarized Rayleigh light scattering of cyclohexane solutions of 1,3-diphenyl-1,3-propanedione (dibenzoylmethane) and its neutral, six-coordinate dibutyltin(IV) and dicyclohexyltin(IV) complexes has been studied interferometrically at the wavelengths 514.5, 488.0, and 457.9 nm. The data clearly indicate that significant preresonance enhancemen...
Dynamic light scattering studies were done on solutions of poly(γ-benzyl L-glutamate) (PBLG) in 1,2-dichloroethane. In this solvent, PBLG exists as a rigid α helix with a length per residue of 1.5 Å and a diameter of 15 Å. The concentration of the solutions ranged between 4 and 50 mg/mL, and the molecular weights of the PBLG were between 150 000 an...
A semiclassical theory relating the molecular resonance Rayleigh scattering intensity to the extinction coefficient of an electronic transition is presented. For isotropic molecules, the theory is shown to be equivalent to classical fluctuation theory. The semiclassical theory is then extended to include anisotropic polarizabilities. Depolarized sc...
Gramicidin is thought to form dimeric helical rods in alcohol solutions. In addition, there is evidence that the rod dimensions change upon addition of potassium ions. The present work reports values for the translational and rotational diffusion coefficients of gramicidin in methanol and 95% ethanol and in these same solvents with added KSCN. Solu...
Dynamic polarized light scattering is routinely used to study translational diffusion of macromolecules in solution. For macro-molecules comparable in size to the wavelength of light, it may also be used to probe macromolecular rotations and long range intramolecular motions. The basic theory of dynamic light scattering from these “large” macromole...
In this work, we use the dynamic light scattering technique of photon correlation spectroscopy to study the properties of micellar dodecyldmethyl-ammonium chloride (C12H25(CH3) 2NHC1, abbreviated DDAC). This system has been extensively studied by S. Ikeda and co-workers1 using surface tension, viscosity, static light scattering and C-13 NMR measure...
Dynamic depolarized light scattering may be used to study rotational diffusion of rigid macromolecules and both local and long range intramolecular motions of flexible macromolecules. It may also be used to probe the rotational motion of small molecules dispersed in polymeric systems. Both the basic theory of dynamic depolarized light scattering an...
Rotational motion of chlorobenzene (CB) in poly(methyl methacrylate) (PMMA) over a range of temperature and chlorobenzene concentration is studied by the depolarized dynamic light scattering technique. It was found that the depolarized spectrum of chlorobenzene in PMMA at concentrations of 20 g of chlorobenzene/100 mL or greater shows two widely se...
