The foundational studies of this dissertation concern the characterization of segmented polyurethanes and polyureas synthesized without the use of chain extenders'molecules that are typically used to promote a microphase separated morphology that gives these materials their useful characteristics. Polyurethanes in which a single asymmetric diisocyanate comprising the whole of the hard segment were found to display poor microphase separation. Conversely, polyurethanes in which a single symmetric diisocyanate composed the hard segment were found to display good microphase separation. The more efficient packing of the symmetric hard segments also led to an increase in hard segment connectivity and hence higher values of storage moduli in these systems. When hydroxyl-terminated diisocyanates were replaced with amine-terminated diisocyanates, polyureas were formed. Here too, diisocyanate symmetry was found to play a key role with symmetric diisocyanates leading to better microphase separation. In addition, the polyurea materials displayed broader service temperature windows than their polyurethane counterparts as the relatively stronger bidentate hydrogen bonding replaced monodentate hydrogen bonding in these materials. A thread-like, microphase separated morphology was visually confirmed using atomic force microscopy. Other techniques such as ambient temperature tensile testing, and wide and small angle x-ray scattering were employed to confirm the presence of the microphase separated structure. The investigation into the effects of diisocyanate chemistry and its symmetry was broadened to incorporate non-chain extended polyurethane materials with different soft segment molecular weights, as well as polyurethanes that did contain chain extenders. Once again the effect of using symmetric versus asymmetric diisocyanates was evident in the structure–property behavior of these systems, with symmetric diisocyanates forming materials that displayed better microphase separation and more connectivity of their hard domains. Lastly, in a departure from the segmented copolymer area, a study was conducted into the influence of casting variables on the solid-state structure of synthetic polypeptide films based on glutamate chemistry. The effect of solvent evaporation was determined to play a key role in the morphology of these polypeptide films. Measured small angle light scattering patterns were compared to computer calculated patterns to reveal information about the structure, shape, and length scale of the polypeptide structure. / Ph. D.

A low-cost, low-temperature packaging concept is proposed for localized sealing and control of the ambient of a device cavity appropriate for Radio-Frequency (RF) Micro- Electro-Mechanical (MEMS) devices, such as resonators and switches. These devices require application specific packaging to facilitate their integration, provide protection from the environment, and control interactions with other circuitry. In order to integrate these devices into standard integrated circuit (IC) process flows and minimize damage due to post-fabrication steps, packaging is performed at the wafer level. In this work Indium and Silver are used to seal a monolithic localized hermetic pack- age. The cavity protecting the device is formed using standard lithography-based processing techniques. Metal walls are built up from the substrate and encapsulated by a glass or silicon lid to create a monolithic micro-hermetic package surrounding a predefined RF microsystem. The bond for the seal is then formed by rapid alloying of Indium and Silver using a temperature greater than that of the melting point of Indium. This ensures that the seal formed can subsequently function at temperatures higher than the melting temperature of pure Indium. This method offers a low-temperature bonding technique with thermal robustness suitable for wafer-level process integration. The ultimate goal is to create a seal in a vacuum environment. In this dissertation, design trade-offs made in wafer-level packaging are explained using thermo-mechanical stress and electrical performance simulations. Prototype passive microwave circuits are packaged using the developed packaging process and the performance of the fabricated circuits before and after packaging is analyzed. The effect of the package on coplanar waveguide structures are characterized by measuring scattering parameters and models are developed as a design tool for wafer-level package integration. The small scale of the localized package is expected to provide greater reliability over conventional full chip packages. / Ph. D.

This study developed and evaluated a 34-item scale designed to measure human and companion animal attachment. A total of 398 individuals, ranging in age from 18 to 87, who have a pet completed the Pet-Attachment Scale (PAS). These individuals also completed the Companion Animal Bonding Scale (CABS), which asks respondents how much caretaking they devote to their pets. The PAS and the CABS were highly correlated, r=-.68 (p<.001), with an overlapping variance of 46%. The inter-item consistency or Chronbach's Alpha of the PAS was .961, compared to a Chronbach's Alpha of .862 for the CABS. The factor analysis of the PAS revealed two factors; Companionship (12 items) and Emotional Fulfillment (7 items). Thus, the PAS can be shortened to 19 items for follow-up research. The factor analysis for the CABS revealed only one factor (i.e., caretaking), and the analysis suggested the scale could be reduced from 8 to 3 items. The strong correlations between the PAS and the CABS suggest concurrent, convergent, and construct validity for the PAS. A stepwise regression for the PAS revealed three significant predictors: 1) responsibility, 2) favorite pet chosen, and 3) gender. Women who were responsible for their pet, and did not select a particular pet as their favorite, scored highest on attachment to their pets. A stepwise regression for the CABS revealed four predictors: 1) responsibility, 2) favorite pet chosen, 3) live with this pet, and 4) gender. These predictors for the CABS were the same as for the PAS, with the addition that those who lived with their pet gave more caretaking than those who did not. Analysis of variance was used to explore the effects of the predictor variables on the PAS and the CABS. These analyses revealed significant effects of gender and age category on both pet attachment (PAS) and pet caretaking (CABS). Women in the middle age category were most attached to their pets (PAS) and gave the most caretaking to their pets (CABS). The unique feature of the PAS, not measured by the CABS, was an Emotional Fulfillment factor. Future research should distinguish between pet attachment as companionship versus emotional fulfillment. / Ph. D.

The synthesis of a variety of novel functionalized polymers using living polymerization techniques to achieve functional and stimuli responsive coatings on silica surfaces are described. Since microscopic features on a surface influence the overall wetting properties of the surface, a systematic investigation of the influence of polymer architecture on the microscopic characteristics of the modified surfaces was studied using silane-functionalized linear and novel star-branched polystyrene (PS). Star-branched modifiers provide functional and relatively well-defined model systems for probing surface properties compared to ill-defined highly branched systems and synthetically challenging dendrimers. Using these simple star-shaped macromolecules it was shown that the topographies of the polymer-modified surfaces were indeed influenced by the polymer architecture. A model explaining the observed surface features was proposed. A living polymerization strategy was also used to synthesize centrally functionalized amphiphilic triblock copolymers. The amphiphilic copolymers exhibited stimuli responsive changes in surface hydrophobicity. In spite of multiple solvent exposures, the copolymer films remained stable on the surface indicating that the observed changes in surface properties were due to selective solvent induced reversible rearrangement of the copolymer blocks. The chemical composition of the copolymers was tailored in order to tune the response time of the surface anchored polymer chains. Thus, the polymer coatings were used to reversibly change the surface polarities in an on-demand fashion and could find possible applications as smart adhesives, sensors and reusable membrane devices. In contrast to the afore-mentioned covalent modification approach, which often leads to permanent modification of surfaces, renewable surfaces exhibiting "universal" adhesion properties were also obtained through non-covalent modification. By employing hydrogen bonding interactions between DNA bases, surfaces functionalized with adenine groups were found to reversibly associate with thymine-functionalized polymers. This study describing the solvato-reversible polymer coating was the first demonstration on silica surfaces. A systematic investigation of the influence of surface concentration of the multiple hydrogen bonding groups and their structure on the extent of polymer recognition by the modified surfaces is also discussed. / Ph. D.

Additive manufacturing (AM) is a rapidly growing and evolving form of product development that has the potential to revolutionize both the industrial and academic spheres. For example, AM offers much greater freedom of design while producing significantly less waste than most traditional manufacturing techniques such as injection and blow molding. Filament-based material extrusion AM, commonly referred to as fused filament fabrication (FFF), is one of the most well-known AM modalities using a polymeric feedstock; however, several obstacles currently prohibit widespread use of this manufacturing technique to produce end-use products, which will be discussed in this dissertation. Specifically, a severely limited material catalog restricts tailored product development and the variety of applications. Additionally, poor interlayer adhesion results in anisotropic mechanical properties which can lead to failure, an issue not often observed in traditional manufacturing techniques. A review of the current state of the art research in the field of FFF, focusing on the multiphysics-based modeling of the system and exploring some empirically determined relationships, is presented herein to provide a more thorough understanding of FFF and its complexities. This review further guides the work discussed in this dissertation. The primary focus of this dissertation is to expand the fundamental understanding of the FFF process, which has proven difficult to measure directly. On this size scale, introduction of measurement devices such as thermocouples and pressure transducers can significantly alter the behavior of the process or require major changes to the geometry of the system, leading to spurious measurements, incorrect outcomes, and/or conclusions. Therefore, the research presented in this dissertation focuses on the development and validation of predictive models based on first principles approaches that can provide information leading to the optimization of printing parameters and exploration of novel and/or modified materials without an exhaustive and inefficient trial-and-error process. The first potential issue a novel material may experience in FFF is an inability to extrude from the heated nozzle. Prior to this work, no efforts were focused on the molten material inside the liquefier and its propensity to flow in the reverse direction through the annular region between the filament and the nozzle wall, referred to as annular backflow. The study presented in this dissertation explores this phenomenon, determining its cause and sensitivity to processing parameters and material properties. A dimensionless number, named the "Flow Identification Number" or FIN, is defined that can predict the propensity to backflow based on the material's shear thinning behavior, the filament diameter, the nozzle diameter, and the filament feed rate and subsequent pressure inside the nozzle. An analysis of the FIN suggested that the backflow potential of a given material is most sensitive to the filament diameter and its shear thinning behavior (power law index). The predictive model and FIN were explored using three materials with significantly different onsets of shear thinning. The experiments validated both the backflow model and a previously derived buckling model, leading to the development of a rapid screening technique to efficiently estimate the extrudability of a material in FFF. Following extrusion from the nozzle, the temperature profile of the deposited filament will determine nearly all of the mechanical properties of the printed part as well as the geometry of the individual roads and layers because of its temperature dependent viscoelastic behavior. Therefore, to better understand the influence of the temperature profile on the evolution of the road geometry and subsequent interlayer bonding, a three-dimensional finite element heat transfer analysis was developed. The focus of this study is the high use temperature engineering thermoplastic polymer polyetherimide, specifically Ultem™ 1010, which had not been studied in prior modeling analyses but presents significant challenges in terms of large thermal gradients and challenging AM machine requirements. Through this analysis, it was discovered that convective cooling dominated the heat transfer (on the desktop FFF scale) producing a significant cross-sectional temperature gradient, whereas the gradient along the axis was observed to be significantly smaller. However, these results highlighted a primary limitation in computer modeling based on computational time requirements. This study, utilizing a well-defined three-dimensional model based on a geometry measured empirically, produced results describing 0.5 s of printing time in the printing process and elucidated great details in the road shape and thermal profile, but required more than a week of computation time, suggesting a need for to modify the modeling approach while still accurately capturing the physics of the FFF layer deposition process. The determination of the extensive time required to converge the three-dimensional model, as well as the identification of a relative lack of axial thermal transfer, led to the development of a two-dimensional, cross-sectional heat transfer analysis based on a finite difference approach. This analysis was coupled with a diffusion model and a stress development model to estimate the recovery of the bulk strength and warping potential of a printed part, respectively. Through this analysis, it was determined that a deposited road may remain above Tg for 2-10 s, depending on the layer time, or time required for the nozzle to pass a specific point in the x-y plane between each layer. The predicted strength recovery was significantly overestimated, leading to the discovery of the extreme sensitivity of the predictive models to the relaxation time of a material, particularly at long layer times. When the deposited filament has enough time to attain an equilibrium temperature, small changes in the relaxation time of the material resulted in significant changes in the predicted healing results. These results highlight the need for exact estimations of the material parameters to accurately predict the properties of the final print. / Doctor of Philosophy / Additive manufacturing (AM), particularly filament-based material extrusion additive manufacturing, commonly known as fused filament fabrication (FFF), has recently become the subject of much study with the goal of utilizing it to produce parts tailored to specific purposes quickly and cheaply. AM is especially suited to this purpose due to its ability to produce highly complex parts with the ability to change design very easily. Furthermore, AM typically produces less waste than many traditional manufacturing techniques due to the process building a part layer by layer rather than removing unneeded material from a larger piece, resulting in a cheaper process. These freedoms make AM, and FFF in particular, highly prized among industrial producers. However, numerous challenges prevent the adoption of FFF by these companies. Particularly, a lack of available material options and anisotropic material properties lead to issues when attempting to produce a part targeted for use in a specific field. FFF is primarily commercially limited to two materials: polylactic acid (PLA) and acrylonitrile-butadiene-styrene (ABS) with a few other materials available in more specialized fields. However, essentially all these materials are limited to low use temperatures (less than 300 °C) and are primarily amorphous or with nearly negligible amounts of crystallinity. This severely limits the ability to tailor a printed part to a specific purpose and restricts the use of printed parts to applications requiring very low strengths. This is one reason why FFF, and most types of AM, is limited to the prototyping field rather than end-use applications. The other reason, anisotropic mechanical properties, is caused by the building methodology of AM. Creating a part layer by layer naturally introduces potential areas of weakness at the joining of the layers. If bulk properties are not recovered, the interlayer bond acts as a stress concentrator under load and will break before the bulk material. The work presented in this dissertation proposes methods to better understand the FFF system in order to address these two issues, leading to the optimization of the printing process and ability to expand the material catalog, particularly in the direction of high use temperature materials. The research discussed herein attempts to develop predictive models that may allow exploration into the FFF system which can be difficult to do experimentally, and by predicting the properties of a printed part, the models can guide future experimentation in FFF without the need for an extensive trial-and-error process. The work presented in this dissertation includes exploring the flow phenomena inside the FFF nozzle to determine extrudability as well as two-dimension and three-dimension heat transfer models with the goal of describing the viscoelastic, flow, diffusion, and stress development phenomena present in FFF.

Bio-inspired monomers functionalized with nucleobase or ionic group allowed synthesis of supramolecular polymers using free radical polymerization and controlled radical polymerization techniques. Comprehensive investigations for the structure-property-morphology relationships of these supramolecular polymers elucidated the effect of noncovalent interactions on polymer physical properties and self-assembly behaviors. Reverse addition-fragmentation chain transfer (RAFT) polymerization afforded acrylic ABC and ABA triblock copolymers with nucleobase-functionalized external blocks and a low-Tg central block. The hard-soft-hard triblock polymer architecture drove microphase-separation into a physically crosslinked hard phase in a low Tg matrix. Hydrogen bonding in the hard phase enhanced the mechanical strength and maintained processability of microphase-separated copolymers for thermoplastics and elastomers. A thermodynamically favored one-to-one stoichiometry of adenine and thymine yielded the optimal thermomechanical performance. Intermolecular hydrogen bonding of two thymine units and one adenine unit allowed the formation of base triplets and directed self-assembly of ABC triblock copolymers into remarkably well-defined lamellae with long-range ordering. Acetyl protected cytosine and guanine-containing random copolymers exhibited tunable cohesive strength and peel strength as pressure sensitive adhesives. Post-functionalization converted unprotected cytosine pendent groups in acrylic random copolymers to ureido-cytosine units that formed quadruple self-hydrogen bonding. Ureido-cytosine containing random copolymers self-assembled into nano-fibrillar hard domains in a soft acrylic matrix, and exhibited enhanced cohesive strength, wide service temperature window, and low moisture uptake as soft adhesives. A library of styrenic DABCO salt-containing monomers allowed the synthesis of random ionomers with two quaternized nitrogen cations on each ionic pendant group. Thermomechanical, morphological, and rheological analyses revealed that doubly-charged DABCO salts formed stronger ionic association and promoted more well-defined microphase-separation compared to singly-charged analogs with the same charge density. Bulkier counterions led to enhanced thermal stability, increased phase-mixing, and reduced water uptake for DABCO salt-containing copolymers, while alkyl substituent lengths only significantly affected water uptake of DABCO salt-containing copolymers. Step growth polymerization of plant oil-based AB monomer and diamines enabled the synthesis of unprecedented isocyanate-free poly(amide hydroxyurethane)s, the first examples of film-forming, linear isocyanate-free polyurethanes with mechanical integrity and processability. Successful electrospinning of segmented PAHUs afforded randomly orientated, semicrystalline fibers that formed stretchable, free-standing fiber mats with superior cell adhesion and biocompatibility. / Ph. D.

Advanced analytical techniques were utilized to investigate the intermolecular forces in several nanostructured materials. Techniques including, but not limited to, isothermal titration calorimetry (ITC), variable temperature Fourier transform infrared (FTIR) spectroscopy, and ultraviolet-visible (UV-Vis) thermal curves were used to study the fundamental interactions present in various nanomaterials, and to further probe the influence of these interactions on the overall behavior of the material. The areas of focus included self-assembly of surfactant micelles, polycation complexation of DNA, and temperature-dependent hydrogen bonding in polymeric systems. ITC was successfully used to determine the low critical micelle concentration (CMC) for a novel gemini surfactant with limited water solubility. CMCs were measured at decreasing methanol molar fractions (xMeOH) in water and the resulting linear relationship between CMC and methanol concentration was used to mathematically extrapolate to a predicted CMC at xMeOH = 0. Using this technique, the CMC value for the novel gemini surfactant was predicted to be 0.037 ± 0.004 mM. This extrapolation technique was also validated with surfactant standards. ITC was also used to investigate the binding thermodynamics of polyplex formation with polycations and DNA. The imidazolium-containing and trehalose-based polycations were both found to have endothermic, entropically driven binding with DNA, while the adenine-containing polycation exhibited exothermic DNA binding. In addition, ITC was also used to confirm the stoichiometric binding ratio of linear polyethylenimine and DNA polyplexes as determined by a novel NMR method. Dynamic light scattering (DLS) and zeta potential measurements were also performed to determine the size and surface charge of polyplexes. Circular dichroism (CD) and FTIR spectroscopies provided information regarding the structural changes that may occur in the DNA upon complexation with polymers. UV-Vis thermal curves indicated that polyplexes exhibit a greater thermal stability than DNA by itself. Variable temperature FTIR spectroscopy was used to quantitatively compare the hydrogen bonding behavior of multi-walled carbon nanotube (MWCNT)-polyurethane composites. Spectra were collected from 35 to 185 deg C for samples containing various weight percent loadings of MWCNTs with different hydrogen bonding surface functionalities. Peak fitting analysis was performed in the carbonyl-stretching region for each sample, and the hydrogen-bonding index (Rindex) was reported. Rindex values were used to quantitatively compare all of the composite samples in regards to temperature effects, weight percent loadings of MWCNTs, and the different functionalizations. In general, higher weight percent loadings of the MWCNTs resulted in greater Rindex values and increased hydrogen bond dissociation temperatures. In addition, at 5 and 10 wt% loadings the initial Rindex values displayed a trend that tracked well with the increasing hydrogen bonding capacity of the various surface functionalities. / Ph. D.

Palladium(II) acetate and palladium(II) chloride react with amino acids in acetone/water to yield cis or trans square planar bis-chelated palladium amino acid complexes. The naturally occurring amino acids and some N-alkylated and substituted derivatives and homologs were evaluated as ligands. Thirty-eight amino acids in total were investigated as ligands. The formation of aquo complexes in water was observed and studied by 13C NMR spectroscopy and modeled by DFT calculations. Each class of amino acid ligand is catalytically active with respect to the oxidative coupling of olefins and phenylboronic acids. Some enantioselectivity is observed and the formation of products not reported in other Pd(II) oxidative couplings is seen. Both activated and non-activated alkenes were oxidatively coupled to phenylboronic acids incorporating both electron-donating and electron-withdrawing groups. The crystal structures of nineteen catalyst complexes were obtained. The extended lattice structures arise from N-H..O or O..(HOH)..O hydrogen bonding. NMR, HRMS, FTIR, single crystal XRD, and powder XRD data are evaluated. / Ph. D.

Developing a fundamental understanding of the interactions of chemical warfare agents (CWAs) with surfaces is essential for the rational design of new sorbents, sensors, and decontamination strategies. The interactions of chemical warfare agent simulants, molecules which retain many of the same chemical or physical properties of the agent without the toxic effects, with amorphous silica were conducted to investigate how small changes in chemical structure affect the overall chemistry. Experiments investigating the surface chemistry of two classes of CWAs, nerve and blister agents, were performed in ultrahigh vacuum to provide a well-characterized system in the absence of background gases. Transmission infrared spectroscopy and temperature-programmed desorption techniques were used to learn about the adsorption mechanism and to measure the activation energy for desorption for each of the simulant studied. In the organophosphate series, the simulants diisopropyl methylphosphonate (DIMP), dimethyl methylphosphonate (DMMP), trimethyl phosphate (TMP), dimethyl chlorophosphate (DMCP), and methyl dichlorophosphate (MDCP) were all observed to interact with the silica surface through the formation of a hydrogen bond between the phosphoryl oxygen of the simulant and an isolated hydroxyl group on the surface. In the limit of zero coverage, and after defect effects were excluded, the activation energies for desorption were measured to be 57.9 ± 1, 54.5 ± 0.3, 52.4 ± 0.6, 48.4 ± 1, and 43.0 ± 0.8 kJ/mol for DIMP. DMMP, TMP, DMCP, and MDCP respectively. The adsorption strength was linearly correlated to the magnitude of the frequency shift of the ν(SiO-H) mode upon simulant adsorption. The interaction strength was also linearly correlated to the calculated negative charge on the phosphoryl oxygen, which is affected by the combined inductive effects of the simulants’ different substituents. From the structure-function relationship provided by the simulant studies, the CWA, Sarin is predicted to adsorb to isolated hydroxyl groups of the silica surface via the phosphoryl oxygen with a strength of 53 kJ/mol. The interactions of two common mustard simulants, 2-chloroethyl ethyl sulfide (2-CEES) and methyl salicylate (MeS), with amorphous silica were also studied. 2-CEES was observed to adsorb to form two different types of hydrogen bonds with isolated hydroxyl groups, one via the S moiety and another via the Cl moiety. The desorption energy depends strongly on the simulant coverage, suggesting that each 2-CEES adsorbate forms two hydrogen bonds. MeS interacts with the surface via a single hydrogen bond through either its hydroxyl or carbonyl functionality. While the simulant work has allowed us to make predictions agent-surface interactions, actual experiments with the live agents need to be conducted to fully understand this chemistry. To this end, a new surface science instrument specifically designed for agent-surface experiments has been developed, constructed, and tested. The instrument, located at Edgewood Chemical Biological Center, now makes it possible to make direct comparisons between simulants and agents that will aid in choosing which simulants best model live agent chemistry for a given system. These fundamental studies will also contribute to the development of new agent detection and decontamination strategies. / Ph. D.

Anionic polymerization and controlled radical polymerization enabled the synthesis of novel block copolymers with non-covalent interactions (electrostatic interaction and/or hydrogen bonding) to examine the relationships between mesoscale phenomenon and macroscopic physical properties. Non-covalent interactions offer extra intra- and inter-molecular interactions to achieve stimuli-responsive materials in various applications, such as artificial muscles, thermoplastic elastomers, and reversible biomacromolecule binding. The relationship between non-covalent interaction promoted mesoscale phenomenon (such as morphology) and consequent macroscopic physical properties is the key to optimize material design and improve end-use performance for emerging applications. Pendant hydrogen bonding in ABA block copolymers promoted microphase separation and delayed the order-disorder transition, resulting in tunable morphologies (through composition changes) and extended rubbery plateaus. Reversible addition-fragmentation chain transfer (RAFT) polymerization afforded a facile synthesis of ABA triblock copolymers with hydrogen bonding (urea sites) and electrostatic interactions (pyridinium groups). Pyridine groups facilitated hydrogen bonding through a preorganization effect, leading to highly ordered, long-range lamellar morphology and a significant increase of flow temperature (Tf) 80 °C above the hard block Tg. After quaternization of pyridine groups, electrostatic interaction, as a second physical crosslinking mechanism, disrupted ordered lamellar morphology and decreased Tf. Yet, extra physical crosslinking from electrostatic interactions pertained ordered hydrogen bonding at high temperature and exhibited improved stress-relaxation properties. Both conventional free radical polymerization and RAFT polymerization generated a library of poly(ionic liquid) (PIL) homopolymers with imidazolium groups as bond charge moieties. A long chain alkyl spacer between imidazolium groups and the polymer backbones ensured a low glass transition temperature (Tg), which is beneficial to ion conductivity. Four different counter anions enabled readily tunable Tgs all below room temperature and showed promising ion conductivities as high as 2.45 × 10⁻⁵ S/cm at 30 °C. For the first time, the influence of counter anions on radical polymerization kinetics was observed and investigated thoroughly using in situ FTIR, NMR diffusometry, and simulation. Monomer diffusion and aggregation barely contributed to the kinetic differences, and the Marcus theory was applied to explain the polymerization kinetic differences which showed promising simulation results. RAFT polymerization readily prepared AB diblock, ABA triblock and (AB)3 3-arm diblock copolymers using the ionic liquid (IL) monomers discussed above and deuterated/hydrogenated styrene. We demonstrated the first example of in situ morphology studies during an actuation process, and counter anions with varied electrostatic interactions showed different mesoscale mechanisms, which accounted for macroscopic actuation. The long chain alkyl spacer between imidazolium groups and polymer backbones decoupled ion dynamics and structural relaxation. For the first time, composition changes of block copolymers achieved tunable viscoelastic properties without altering ion conductivity, which provided an ideal example for actuation materials, solid electrolytes, and ion exchange membranes. / Ph. D. / My research focuses on the synthesis of novel soft materials with a special interest in responsive polymers. The incorporation of responsive chemistry, such as hydrogen bonding and ionic interactions, enables soft materials with complex responsive behavior were achieved. Polymers with ion pairs promise great potential as solid-state electrolytes (which transfer ions to generate current) to eliminate potential fire hazard in batteries, which has been an arising concern for modern cellphone and electric car industry. The introduction of strong dipoles into polymers allows the fabrication of actuators, which convert electric signals to physical movement. Under applied voltage, polymers bend within seconds while holding physical loads. Actuator studies in polymers paves the way towards artificial muscles as well as soft robotics. Temperature responsive hydrogen bonding in polymers offers drastically different viscoelastic properties at different temperature and serves as the key mechanism in holt-melt adhesives, controlled drug release, and high performance materials.