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The linear gradient quality and the control over chain length and endgroup functionality in the copolymerization of acrylates, methacrylates, and styrenes via atom transfer radical polymerization (ATRP) are evaluated by detailed kinetic Monte Carlo simulations with explicit tracking of macromolecules. In all simulations, diffusional limitations on termination are taken into account. The linear gradient quality is characterized by a linear gradient deviation ⟨GD⟩ ranging between 0 and 1. For a ⟨GD⟩ value of 0.06 or lower, the linear gradient quality is defined as excellent, whereas for ⟨GD⟩ values higher than 0.25 gradient copolymers of poor quality are formed (targeted chain length (TCL) = 100). Under batch ATRP conditions, using a catalytic system consistent with Cu(I)Br/PMDETA (PMDETA = N,N,N′,N″,N″-pentamethyldiethylenetriamine), an excellent control over chain length and end-group functionality is possible, and copolymers with a good linear gradient quality at final conversion can be prepared. Moreover, for sufficiently high conversions and depending on the monomer reactivity ratios, a strong correlation exists between ⟨GD⟩ and the polydispersity index (PDI), allowing an approximate assessment of the linear gradient quality based on PDI. For higher targeted chain lengths, this correlation shifts toward lower ⟨GD⟩ values under controlled ATRP conditions.

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A comprehensive kinetic Monte Carlo (kMC) model is used to interpret and better understand the results of a systematic experimental investigation of activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) of butyl methacrylate (BMA) using Sn(EH) 2 as reducing agent, ethyl 2-bromoisobutyrate (EBiB) as ATRP initiator, and CuBr 2 /TPMA (TPMA: tris[(2-pyridyl)methyl]amine) as deactivator. The model demonstrates the importance of slow initiation, with distinct activation and deactivation rate coefficients for the initiator and polymeric species required to match the experimental data. In addition, the model incorporates a second reduction step for the reducing agent and accounts for diffusional limitations on chainlength-dependent termination. The effect of temperature on the slow ATRP initiation is limited, and a sufficiently high initial reducing agent concentration is crucial to obtain a high conversion, although achieved at the expense of decreased end-group functionality.

The performance of polymeric materials depends strongly on the control over the polymer microstructure during the synthesis step. In this review, attention is paid to the potential of microkinetic modelling to facilitate the identification of optimal reactants and reaction conditions to design the polymer microstructure in bulk and solution (post) polymerisation processes. Focus is on living polymerization, reversible deactivation radical polymerization (RDRP) and "click" chemistry techniques, covering both batch and continuous synthesis approaches. A description according to the increasing level of macromolecular detail and thus modelling complexity is provided, including not only the characterization of the polymer microstructure via a finite number of variates (e.g. chain length, overall composition and branching content) but also its explicit visualisation by the simulation of the architecture and monomer sequences of a representative number of individual polymer chains. Several complementary case studies are included to demonstrate the high relevance of model-based design for the development of improved and novel synthetic protocols for precision control

The importance of the development of kinetic modeling tools to mechanistically understand and design bulk and solution reversible addition fragmentation chain transfer (RAFT) polymerization is highlighted. Both deterministic and stochastic kinetic modeling methods are covered, considering a detailed reaction scheme and accounting for the impact of diffusional limitations on the reaction rates. A novel strategy is introduced to fundamentally calculate the diffusional contributions for the apparent RAFT addition and fragmentation rate coefficients. Next to literature examples, case studies are included to demonstrate that detailed theoretical studies are indispensable to completely map the effect of the polymerization conditions and RAFT agent reactivity on the control over microstructural properties and the overall polymerization time. Guidelines for future kinetic modeling activities are formulated to enhance joined theoretical and experimental research.

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The three-dimensional arrangement of natural and synthetic network materials determines their application range. Control over the real time incorporation of each building block and functional group is desired to regulate the macroscopic properties of the material from the molecular level onwards. Here we report an approach combining kinetic Monte Carlo and molecular dynamics simulations that chemically and physically predicts the interactions between building blocks in time and in space for the entire formation process of three-dimensional networks. This framework takes into account variations in inter-and intramolecular chemical reactivity, diffusivity, segmental compositions, branch/network point locations and defects. From the kinetic and three-dimensional structural information gathered, we construct structure-property relationships based on molecular descriptors such as pore size or dangling chain distribution and differentiate ideal from non-ideal structural elements. We validate such relationships by synthetizing organosilica, epoxy-amine and Diels-Alder networks with tailored properties and functions, further demonstrating the broad applicability of the platform.